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When one condenses the literature that is available, especially recent literature on how to generate a useful metric that correlates well with human hearing and sonic preferences, it becomes clear that most amps are simply designed wrong from a psychoacoustic POV.
Based on the work of Crowhurst, Cheever, Geddes, Otala, white papers by Pass etc. you start to realize that you need the following:
1) A harmonic distortion pattern that is monotonic (i.e. decreasing exponentially with increasing harmonics)
2) Little to no high order harmonics and no high orders without corresponding lower order harmonics
3) No excessive bass distortion harmonics (mainly transformer coupled amps)
4) No excessive high frequency noise or distortion (mainly SS or D amps but also some tubes with negative feedback)
5) No generator of high order or IMD high order harmonics
6) low to no phase shift anywhere near the passband
7) Flat distortion profile vs. frequency (most amps rise in the highs or bass or both).
This means an amp design that inexorably leads to single ended concepts:
1) Push pull amps cancel even order harmonics...not perfectly but enough that it destroys monotonicity. Doesn't matter if it is tubes or SS but tubes seem to remove less even harmonics so maybe by being "less perfect" they are inadvertently doing less damage
2) Negative feedback: It destroys monotonicity by design. It unbalances the pattern relationship between low order and high order harmonics. It suppresses low order and generates high order harmonics. This leads to an unnatural balance.
3) Bass distortion: A problem for many tube amps that are using too small output transformers and saturate. If this is addressed properly the distortion can be very small
4) High frequency noise and distortion. Most SS and D amps suffer from a rise in distortion (sometimes more than 10x) often from as low as 1Khz. Not only is it an increase in amount, often the pattern changes and shows large amounts of high order, sonically detrimental harmonics
5) Crossover distortion: Many Class AB amps have this problem...although some have obvious problems and some have very subtle problems. If an amp has this problem then negative feedback won't reduce it. You would think that most bias their amps enough at least to minimize it but you can still see it regularly in STereophile measurements.
6) Distortions related to Global negative feedback loops. Explored extensively by Otala and found to have some serious consequences also with the speaker/amp interface.
7) Distortion vs. frequency: I have only seen this be flat in very few amp designs. Most have either bass distortion increase, high frequency increase or both. Only properly designed, low or no feedback amps seem to be able to achive this. Usually they are also Class A (I know of at least one exception, the Einstein "The absolute tune")
So, what does that leave us with?
No push-pull, either tube or SS or D, unless deliberately designed to not have perfect cancellation of even order harmonics (this will likely cause other unpleasant distortions).
No or very low negative feedback: Clearly unbalances a more "natural" harmonic ordering and has a host of other potential distortions when interacting with real speakers. All harmonic distortion degrades sound quality so it is not about "euphonic" distortion but more or less audible distortion AND more or less offensive distortion.
No Class B or AB: Crossover distortion is an issue and must use negative feedback otherwise distortion would generally be unacceptably high and highly audible. A typical Class AB PP amp will have several % distortion but not of the mainly benign 2nd order like a SET. It will already have lots of high order harmonics polluting the sound (see Boyk and Sussmann for numerical simulations...however, they only modeled Class A circuits...Class AB are much worse).
No small output transformers: Bass distortion is a major problem with most tube amps, PP or SET. It is usually due to cost cutting as transfomers are expensive. This is probably one of the main causes of "tube" sound that people use in a derrogatory manner. Saturation of the output or interstage transformer should be avoided at all costs.
So that leaves us with only a handful of properly designed and made single ended amplifiers as MEASUREABLY closest to what models are saying should be the least audible distortion. Once proper weighting of distortion components and output levels are computed it seems clear.
I did some of this (for fun if you can believe it) with an excel spreadsheet and data I took from Soundstage and STereophile and simply using the Shorter calculation (it is a lot easier than the Cheever or Geddes metric). It was enlightening, once weighted the lowest THD amps fell behind the "high distortion" amps because of the very strong weighting as you get above 9th or 10th harmonics. SETS fared quite well when weighted, even with this inadequate weighting.
It is possible that SEP (pentode) or SE(T) (transistor) or SE OTL amps could also fare well if they don't use much feedback (like a Pass First Watt for example).
Follow Ups:
The original Victrola playback design has yet to be surpassed.
Yes and no, I dont think we can say so , seeing they are playing with modern built electronics into vintage speakers. Until there's a direct comparison with modern CLass-A speakers of similar level, hard to say really.
In my case we're talking about a very pure and direct pathway from needle, to horn, to listener. No electrical amplification at all.
I'm a true believer now, there's no going back.
As long as the damping factor is > 5 there are not significant variations with most speakers. Some SETs even manage this. Even so, the variation is less than the speaker will have intrinsically. This means you are adding a bit more variation in the FR of an already non-flat device.
Edits: 10/02/15 10/02/15
Exactly, and this is why I think this "issue" that the SS amp guys like to bring up is largely a non-issue.
I don't mean to be argumentative, but your original post implies that you have a better idea. If "most" are "wrong", then, which designs are "right"?
:)
"So that leaves us with only a handful of properly designed and made single ended amplifiers as MEASUREABLY closest to what models are saying should be the least audible distortion."
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
nt
try it! you know you want to!
Have you been paying any attention at all?
The measured level of low ordered harmonic distortion, unless very very high, doesn't matter much at all but even just a tiny bit of measured upper ordered distortion matters a lot.
So, of course measurements matter.
It's THD that doesn't really matter. THD, by itself, is not enough information to have any real meaning.
To place things in proper perspective, in terms of audibility, the measured distortion needs to be multiplied by the square of the order.
1% of 2nd would be 4%
.5% of 5th would be 12.5%
.05% of 21st would be 22.05%
.05% of 31st would be 48.05%
.005% of 81st would be 32.805%
Unless the amplifying devices themselves are perfectly linear (and none are) a conventional push pull amplifier that uses GNF produces harmonic distortion all the way out to the 81st order.
My 300b SET amplifier, at the power levels that I use it, produces harmonic distortion out to the 3rd order.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
... a rubbish postulation about the relative negativity of orders of HD.
If you prefer your SET over robust amplifiers it is because of its low-order HD, not its lack of high-order HD.
I love the music of Dmitri Shostakovich
"a rubbish postulation"Do you even know who you are accusing of delivering rubbish?
You are free so say what even you want but you are showing your ignorance.
"...it is well agreed that orders higher than third are more audible and less musical."
Can you guess who said that?
Edit; It was Nelson Pass.
I found this quote from you "One thing discovered by Pythagoras 2500 years ago was that high-order harmonics sounded bad -- harsh, discordant. Nobody is really arguing with Morricab and his ilk that high-order sounds good , only that there is some level where it's inaudible. "
OK, at what point is 81st inaudible?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/25/15
\Or maybe at what point is it produced at all?Nelson Pass himself seems to have suggested an answer of sorts. Consider this chart from his 'Audio Distortion and Feedback' treatise ...
This seems to imply that 81st order distortion won't happen at any conceivable level of feedback; apparently not at 40dB or .0001% distortion (which is as far as the graph goes).
Visually extrapolating, (red line added), Pass's chart it pretty much looks like all practical levels of high-order HD will emerge before 20dB of feedback -- higher than the 6th order illustrated to be sure, but at a steeply diminishing level.
Something that Pass didn't dwell on in his article is that fact that more feedback lowers ALL orders of distortion.
BTW, I own Pass Labs amp and like it a lot.
I love the music of Dmitri Shostakovich
Edits: 09/26/15 09/26/15 09/26/15
Don't you realize the reason that this chart stops with 6th order harmonics...it was too difficult before powerful computers to continue out the computation. You want to see examples of distortion going out at least to 20th order then all you have to do is look at stereophile measurements or soundstage measurements.
Here is an example...and it is a highly touted SS amp.
http://www.soundstage.com/measurements/dartzeel_nhb108_model_one/
I'm not sure that darTZeel is a typical SS amp. It's THD+N is actually rather high for a high-end amp at 0.2 % into 8 Ohms.
But yes, it's highly touted; are its proponents crazy?
I love the music of Dmitri Shostakovich
Just picked a more obvious one, there are many more that measure similarly. Nothing special in this day and age for the Soundstage measuring gear...Stereophile gets similar results with many amps.
Just wanted to illustrate to you that it most certainly doesn't stop with the 6th harmonic and that is just simple harmonics with a single frequency!! Once you add intermodulation effects it is as Nelson says, "The elephant on the dance floor".
What you see with the darTZeel is interesting because it further murks up the waters.
You called Manny ..?
Do you own FM Acoustics amps? When I was a reviewer I almost reviewed their products but got side tracked into a bunch of preamp reviews. I see nothing in their literature or design briefs to suggest a special magic there though. Probably very low measured distortion and a lot of negative feedback and of course push/pull and Class AB...basically nearly all that is conceptually wrong.
Only fooling around his Phono Stage Currently, preferring instead to get a used GT3 or a new Boat . :)I met Manny through other associates for years ,First in the 90's when he was the only one at CES at the time demoing with analog,(mid 90's) etc. His stuff was always highly regarding both for domestic usage and in studios around Europe, many toobites went over to SS because of Manny especially in ASIA.
we have different requirements IMO no tooby matches top notch SS for realism and drive, maybe on 100+ db hugemongous Horns, Alchemist do prefer them thou, for that magic. Anyway just to make sure I'm not mistaken after 40 years involvement, back and forth, I'm going to start fooling with them again, less see if my memory fails me.Condemnation without investigation is prejudicial ..... :)
Edits: 09/30/15 09/30/15
" IMO no tooby matches top notch SS for realism and drive"
Not sure what you mean by realism here because that is absolutely NOT what I hear...tone is all wrong, microdynamics wrong, 3d imaging wrong...just wrong. Drive? I guess if your speakers use bat poop for drivers (pretty close to 0db/watt sensitivity I would guess) and need 50 amps of current then ok but for dynamics a good tube amps SOUNDS much more open and free dynamically...on suitable speaker of course...;-).
SET, the alchemist choice ..... :)In case you missed the current trend , most Horn speakers are now being demoed with SS, including the mega buck Magico.
Edits: 09/30/15
Only here and there...tubes dominate horn demos...
Alon Wolf seems to be a tube denier so no surprise there. Most concluded that the room didn't sound so great (could have just been WAY too loud). For sure the speaker has serious potential...as it should for mega bucks.
As for Avantgarde, they like their own, homegrown SS but I have never heard them sound very good with their own amps. They sounded GREAT this year in Munich with a Lampizator DAC and AudioPAX monos. Really truly Great.
Tune Audio Anima used a Modwright SS amp (the rest behind was tube though) and it was significantly worse than the year before where it was all tubes.
The rest of the big horns at Munich used tubes.
The Line Magnetic WE replica horns sounded amazing with huge LM amps at a show in 2013 in Switzerland.
The REAL WE horns with Silbatone was utterly beguiling and literally brought tears to my wifes eyes when a Russian opera singer came on.
The big daddy Living Voice was its usual unbeatable self running a full Kondo rig this year.
Acapella always demos with Einstein in Europe
So, I am not sure beyond the one Magico and Avantgarde who is running SS regularly on horns. That said, I would think the First Watt SIT-1 would have serious potential on horns...as I said I am not opposed to transistors per se...just how they are typically used.
"The REAL WE horns with Silbatone was utterly beguiling and literally brought tears to my wifes eyes when a Russian opera singer came on."
-Morricab
Was this a mono or stereo demonstration ... ?
Not sure the Guy smelt a rat and wouldn't let Morricab near one ... :)
Mike Lavigne uses one and rates them highly, Mike is a serious player at the pointy end of hi-fi , so i would have to say there is something there, even thou it fails my technical punch card.
nt
try it! you know you want to!
Pass says, " Negative loop feedback creates higher order distortion harmonics, and there seems to be an implication that you might want to use lots of feedback if you plan on using any at all. Some designers look at it this way, others to use feedback sparingly, and some refuse to use it at all. "
He fits indo the "use feedback sparingly" school, in support of which he shows this graph based on his own experimentation ...
I don't see how this supports "sparingly" vs. not at all, but it is worth noting that he only tried 15dB of feedback, not 40dB.
I love the music of Dmitri Shostakovich
but indeed he never says he tried it...Putseys, on the other hand, does go there, and he, as well many others, seem quite pleased with the results.
All of this talk about the superiority of certain types of distortion over others, the superiority of certain distortion profiles over others, and then the claim that what is really "best" is no distortion (what a surprise!) all the while putting down an amp with inaudible IM distortion products and THD below the noise floor makes no logical sense. Since it is indeed all subjective, that is par for the course...
try it! you know you want to!
That is that the zero feedback crew LIKE 2nd order distortion; it is this that they like, not the lack of minute amounts of high-order.
I love the music of Dmitri Shostakovich
Again with this myth...Sigh...
nt
try it! you know you want to!
Sorry, had you confused with someone else....
How's the SNR and the frequency response with load on the 300b? Max power output? How does it work with planar or electrostatic speakers at decent volumes in average or better sized rooms? At what level does it start clipping?
How does the IMD compare to:
try it! you know you want to!
nt
try it! you know you want to!
Lets pretend you were asking me this question.
"How's the SNR and the frequency response with load on the 300b?" (2A3)
-I don't know.
"Max power output?"
-One watt.
"How does it work with planar or electrostatic speakers"
-Irrelevant, since it is not practical to power those pigs with a top-shelf amp.
"in average or better sized rooms?"
-Excellent.
"At what level does it start clipping?"
-These amps don't clip baby!
△ᴉʇɐuᴉɯnllI oᴉpn∀△
I believe Tre was using the weightings that were originally developed by D.E.L. Shorter in the early 1950s. He felt that his rather simple weighting scheme was superior to unweighted harmonics...Cheever later found that it didn't go far enough and that level dependence should also be included in the calculation of impact from high order harmonics.
What this also means then is that the sensitivity of your speaker is relevant when talking about what distortion pattern your amp should be generating as it will effect the output power drawn and the harmonics generated vs. what is audible.
Agree , speaker to amp relationship , ur finally admitting to this importance ....
What the obvious implication is that an inefficient speaker in a big room at high volume can never sound optimally as it will be hindered by the quality of the amps that are required to get the desired volume levels. Sorry if you missed that point.
So, unless you have a sensitive, relatively easy to drive big speaker that is not a horn, like the original Wilson X1 Grand SLAMM (95db/watt and an easy load) then your screwed with regard to ultimate sound quality...sorry...
A line source is a possible exception that will work with moderate power because they project the sound into the room as a cylinder rather than a sphere.
"How does it work with planar or electrostatic speakers"
-Irrelevant, since it is not practical to power those pigs with a top-shelf amp.- Garyoyle
Hey Now ,
So planers and ESL are pigs because your desktop radio has only one watt
:)
"Hey Now ,
So planers and ESL are pigs because your desktop radio has only one watt"
Pretty much lol. Only a dump truck needs dump truck tires!
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Well no sensible person would use a desktop 1 watt radio to drive one ...
"Well no sensible person would use a desktop 1 watt radio to drive one ... "I agree, same as me not using 200w to drive 101 db per watt speakers. lol
Horse for courses.
Like Tre's, my system goes louder then I can comfortably stand to listen to.
I sit around 4' or 5' from the speakers, that location can see 104 db peaks, if I am estimating correctly. That's fackin loud enough for me man! lol.
The volume slider rarely goes over 1/2 way.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/23/15
I actually don't have enough gain in my system to clip my tubes.
In fact, full output of my CD player would cause my 300b to produce 2 watts.
And I run my AVC about 6 to 10 clicks down (2db per click).
So I'm no where near clipping.............ever.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
2 watts max, what! you listening at the level of inaudibility, you have Morricab beat by 28 watts ..
:)
Edits: 09/23/15
"...you have Morricab beat by 28 watts"I don't understand.....
"2 watts max, what! you listening at the level of inaudibility...."
No. My speakers are 97db per watt. I have two of them in the room and 2 watts to drive each with.
That would give me 103db peak.
If the music I listen to has 16db peak to average then I can listen at 87db average. If 20db peak to average then 83db.
85db for 8 hours straight will do permanent hearing damage.
I don't think I ever listen that loud.
BTW I don't use tubes amps for bass for a couple of good reasons.
Edited to correct math errors.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/23/15
Tre,2 watts wont give you 106db from 97db ... not to mention listening distance ..
Edits: 09/23/15 09/23/15
To start with listening distance only enters the equation when your speakers are outdoors.When inside a room the reverberate field takes over at just about one meter in most rooms. (just look it up or ask Paul Joppa)
But yes, I misspoke. 2 97db speakers drive by 2 watts each would give 103db. 100db from each, so added together that's 103db. My mistake. Sorry!
BTW You didn't say what you meant by "you have Morricab beat by 28 watts "
OK I got it.
His Pure Sound A30 doesn't even belong in the same room as his SET.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/23/15 09/23/15
in fact its not! tv duty only... the SETs are upstairs in the big rig
Smart man.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
In case you missed it, from PC audio forum:
"Gargoyle, you need to refrain from stepping into threads with the intention of trolling, or just adding nothing of substance.
You've been officially warned."
try it! you know you want to!
In case you missed it from THIS forum:
"TO: kuribo and E-Stat
- Cease responding to one anothers' posts.
- If you disagree with each others' response to a post, whether a matter of fact or opinion, direct your alternative perspective to the original poster (so long as it was neither of you). When doing so, do not refer to, obliquely or otherwise, or in any way comment in a manner that impugns, the other; The Bored will be the sole judge of whether or not this has happened and will act accordingly.
- Failure on either of your part to hold up this directive will result in a ban.
- Don't use the Asylum Emailer services to communicate with each other.
Thank you for your immediate cooperation.
BTW kuribo, your non-communication orders with morricab, Jim-whatever-he's-calling-himself-these-days, and jackman stand."
lol.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
nt
try it! you know you want to!
Flying a little to close to the sun in Morricabs thread? lol
Anyhow, I really do want to see your setup, it would help us have some context.
Is it because you are running 85db bookshelf speakers? That is OK, we are not here to judge.
I'm assuming you have the pucks in a chassis by now?
I can share my info if you want, I got build threads, pictures, WinISD, and SPice! Nothing to hide here!
Cheers
△ᴉʇɐuᴉɯnllI oᴉpn∀△
... we really do want to see your setup, too. It would help us have some context. Unless, of course, you're just trolling, again; something for which we are rapidly losing patience.
Fax mentis incendium gloria cultum, et cetera, et cetera...
Memo bis punitor delicatum! It's all there, black and white,
clear as crystal! Blah, blah, and so on and so forth ...
"Unless, of course, you're just trolling, again; something for which we are rapidly losing patience."How is this possibly considered trolling, are you having a bad day?
"... we really do want to see your setup, too. It would help us have some context."
Sure, go nuts, there are pages of information already on here!
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/24/15
> > ... are you having a bad day?
Nope. Just taking into consideration your posting history here and elsewhere on the Asylum. It speaks for itself.
Fax mentis incendium gloria cultum, et cetera, et cetera...
Memo bis punitor delicatum! It's all there, black and white,
clear as crystal! Blah, blah, and so on and so forth ...
If I might jump in here for a moment...
I haven't posted my equipment largely for two reasons: People use the info to judge another person's "audiophile credentials", and, I don't like to broadcast what's in my house. Know what I mean?
:)
nt
try it! you know you want to!
"I don't like to broadcast what's in my house. Know what I mean?"
That's the other reason I like my "not so pretty" DIY stuff.
Who would want it? Most audiophiles aren't thieves.
On the other hand, that pretty, shiny, sparkly store bought stuff........
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Yeow Gary , Why not post yours while you are at it ......
Regards
Look at the 1-2K range , see anything ....
nt
try it! you know you want to!
But can anyone do all that in a mass market device (so the company can make a decent profit selling to other than the limited audiophile market)at a decent price and light weight (for low shipping costs) that can drive almost any of today's speakers (100-200 wpc and stable/flat frequency response into 4 ohm loads or lower), be used in multichannel installations and subwoofers and runs economically 24/7 (so no warmup required) and low maintenance (poll the world and see how many want to be fiddling with tube amps no matter how good they sound) and gives off little heat so one doesn't need to use noisy/expensive air conditioning in the room and can be made in China and used elsewhere without burning the house down?
(Sorry for the run-on sentence).
"But can anyone do all that in a mass market device (so the company can make a decent profit selling to other than the limited audiophile market)at a decent price and light weight (for low shipping costs) that can drive almost any of today's speakers (100-200 wpc and stable/flat frequency response into 4 ohm loads or lower)"
No, true high fidelity is expensive to make and probably always will be. I didn't think this forum was about mass market...but all this talk about Class D is starting to make me think otherwise. Why does light weight in an amp matter to you?? Do you want to slip it in your pocket for a road trip? I can understand heat as some of my amps have been real cookers but beyond that I don't see the appeal. A Class A/B chip amp has much more appeal.
First, you have been sold the lie that you need at least 100 watts to drive a speaker to a suitable level. As long as the speaker is reasonably sensitive, 20 or 30 watts is plenty. Speakers that are very low impedance will never realize their full potential because they need to be driven by inferior amps. I have yet to go to a home or a show where a low sensitivity speaker driven by monster amps sounds truly realistic...even if it gets the dynamics right the tone is wrong and or the soundstaging or low level resolution or all of it. Many of the insensitive speakers actually compress very early and never achieve realistic dynamics anyway, regardless of the power you put into them.
"be used in multichannel installations and subwoofers and runs economically 24/7 (so no warmup required) and low maintenance "
Again I think you might be on the wrong forum...could be mistaken but your post is highly suggestive.
I was very happy with a 5wpc single ended tube amp driving some Klipsch Forte II but ended up selling the Klipschs to try some Magnepans. That little amp was the best I've ever heard, but you should have seen the trouble I had selling it! If I had trouble selling a made-in-USA tube amp like new with enough tubes for a lifetime for under $500 (no takers for my original $900 asking price), how would a manufaturer stay in business selling them for multiple times that amount?This isn't about what I think at all. I love single-ended tube amps. But manufacturers have to sell stuff to stay in business. Not just to ten or twenty audiophiles on a forum. And when they ship them they won't sell too many if they weigh 50 pounds each. If you think that current manufacturers are missing the mark, try starting a company yourself with your own money and see how well you do. Your bank manager will be more than concerned with your distain for the buying power of the mass market.
As far as SS goes, do you envision 100 more companies like First Watt? How many of them would survive more than a month or two? I dare you to try.
Edits: 09/22/15
Well the weight of history definitely causes a problem with buyer's perceptions...also the desire to sit in front of a stereo system and just listen to music does not seem to fit with many modern lifestyles.
That said, top quality anything is always a niche product. However, we are on a forum of supposedly fanatics about music reproduction...
I never said it was a good or easy business model. However, if all manufacturers stopped you are much more likely to be able to build a good sounding SET amp yourself than a complex Class D or transistor amp yourself.
I was talking about the whole concept of what makes an amp sound the best given the non-linear amplification technologies at our disposal.
It would be really great if someone could figure out a truly linear amplification device...maybe it is not even theoretically possible given physics as we know them??
First, you have been sold the lie that you need at least 100 watts to drive a speaker to a suitable level. - Morricab
Agree, he is being sold a lie alright ..... LOL :)
Edits: 09/22/15
From his reply it seems he more or less agreed with me...at least about the power :)
Even Ralph admitted to using way more than your alotted 30watts and his speaker has more sensitivity Than yours.
Realism , some want it ... :)
depends on room size and volume level considered live. i can easily achieve live levels undistorted in my room and have measured it....have you?
An amp that can't put out enough clean power with a flat fr vs load with most modern speakers is irrelevant today.
try it! you know you want to!
Holy smokes, I had to take a breath in the midst of reading this post.
"But can anyone do all that in a mass market device (so the company can make a decent profit selling to other than the limited audiophile market)at a decent price and light weight (for low shipping costs) "
-Yes, they make refrigerators and ovens everyday.
" that can drive almost any of today's speakers (100-200 wpc and stable/flat frequency response into 4 ohm loads or lower)"
-Yes, they made great speakers years ago, they can still make them today.
The watts per channel and 4 ohm requirement you state is nonsense. Those speakers are a product of their environment.
"be used in multi-channel installations and subwoofers"
-Again, nonsense.
Multi-channel is modern marketing hype that really doesn't do anything better then stereo. Two ears, two speakers.
Most music is native stereo, so aside from the neat parlor trick watching movies, surround it is useless.
Sub woofers are a matter of semantics. You wouldn't need a separate speaker enclosure if you just bought a 3-way to begin with.
Plus mono bass sucks.
"and runs economically 24/7"
-Well that would be open to interpretation.
Overall efficiency would be rated by the wattage used at the wall plug vs the sound pressure being produced.
A 100watt SS amp putting out 95db would use at least twice the power at the plug then say a 1 watt SET that puts out 95db using only 50w from the wall.
You are confusing yourself with intermediate part parameters instead off looking at the system as a whole.
"(so no warmup required)"
-You must be extremely impatient.
"and low maintenance "
-It's a small price to pay. Well made conservatively run tubes will run for years, longer then many will keep their current iPhone.
"and gives off little heat so one doesn't need to use noisy/expensive air conditioning"
-You are being dramatic. Some people are still using incandescent light bulbs which collectively create way more heat and electricity costs in their houses compared to a little tube amp that has a couple of filaments that use less power then a pair of 60watt light bulbs.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Lynn Olson had a good principle:You are either listening to an inherently clean, low distortion device/topology (like SE DHT); or
You are listening to an inherently dirty, high-distortion device/topology (pentodes, transistors, class AB etc), which must be corrected by feedback, and thus the overall result is largely the characteristics of that feedback.
What are the clean, linear, low-distortion devices? We know what they are, mostly the DHTs in the world of tubes, although there are some good IHTs as well, and the small signal jfets or power SITs in the world of transistors. Power pentodes, transistors, MOSFETs etc. are all rather nonlinear; plus, they are current-amplifying rather than voltage-amplifying devices, which typically need some form of feedback to convert to voltage amplification.
Inherently high-distortion topologies include all Class AB approaches. Even if they are still technically used within the "Class A" envelope, the device is typically highly nonlinear near its cutoff, requiring feedback correction.
The problem with Class A outputs is that they are highly inefficient and generate a ton of heat.
Of the various feedback options, I tend to focus on degenerative feedback (i.e. a follower output) as being the least-bad of the bunch.
This leads us to:
SE topologies, no feedback, and very linear devices like DHTs or power SITs perhaps;
PP topologies, no feedback, Class A, and very linear devices like DHTs or power SITs;
PP topologies, degenerative feedback (follower topologies), Class A, MOSFETs or pentodes
SE topologies, degenerative feedback (followers), Class A.
I am interested now in the PP topologies as they are inherently "balanced." PP's bad reputation I think is related to the fact that the widespread use of PP (after WWII in tubes) was also accompanied by Class AB, "Ultralinear" outputs, global feedback & etc. etc. PP approaches with Class A and no feedback, such as Olson's Karna amplifier, remain rare.
MAAAAYBE certain topologies that contain a TON of feedback like 60+db, typically with close attention to gigahertz-range effects and other delicate details. This is the case with the "chip amps" based on LM1875 or LM3875, which I think often sound quite nice in practice. It is also the case, for example, with the Hypex NCore devices, which apparently have 60+db of feedback.
Using follower topologies (degenerative feedback) with super-high transconductance devices like a power MOSFET is also a case of very high feedback.
I don't think that just looking at THD charts is so informative. One effect of feedback is to translate harmonic distortion into nonharmonic distortion -- in effect, something like white noise. And isn't that what we find with many high-feedback approaches, that it is "flat, bland and bleached out" (white noise?) even when measured THD is tiny?
Edits: 09/19/15
Morri,
Whats the short list based on your spread sheet ..
I happen to be convinced that overall amps without NFB sound more real, whatever that really means. But there really are trade offs. Static distortion certainly goes down. Frequency response certainly is better without the interaction of the speaker load and the high output impedance of an NFRB amp. And to add one more the bass is better controlled in an NFB amp. It's sort of like two people getting 90s in the same exam. But both missed completely different questions. Does that mean they both have the same amount of knowledge about the test subject?
A properly designed SET has frequency extension well above hearing and bass well below 20Hz that is powerful and controlled. The lack of control is largely due to Saturation of undersized or poorly made OPTs. Conceptually there is no reason for either issue it is purely execution issues.
With ant transformer amp it's difficult to get a low enough output impedance for either flat response with a reactive load or good bass control unless so much negative feedback is used that the amp would end up unstable. There's no other way around this for either SE or PP tube amps. It's the nature of tubes and output transformers no matter what the deatils of construction. This doesn't make a normal tube amp useless just flawed, that is colored, in ways some like and others don't like. You pick your sound color.
As long as the damping factor is > 5 there are not significant variations with most speakers. Some SETs even manage this. Even so, the variation is less than the speaker will have intrinsically. This means you are adding a bit more variation in the FR of an already non-flat device...big deal.
A damping factor of 5 is significant with differences of over a dB or so unless the speaker impedance curve is very flat and that is a rarity indeed. Try at least 20 and there are still small variations which will subtly color the sound, not so much as overt colorations but sense of distance, openness, even detail depending on how wide and where the dips and bumps are.
my lightly modified 1960s Mc 275s.
Jeremy
WHat is 1db (+- 0.9db to be more precise) when most speakers are at best +-3db in a typical room (usually much worse than that)?
http://www.audioholics.com/audio-amplifier/damping-factor-effects-on-system-response/damping-factor-effects-on-system-response-page-2
And compromise means that ultimately, we each evaluate the strengths and weakness and choose a product that suits our individual preferences. And clearly these personal preferences vary. In the end, when amp performance reaches a certain level, there is no "best", there are only different amps for different compromises.
try it! you know you want to!
Nothing is perfect or "best" in every situation. It comes down to tradeoffs. How those tradeoffs are ordered is entirely personal preference.
try it! you know you want to!
In other words, those that use global negative feedback to "correct" events that have already passed. TIM, anyone? Especially bad when the output filter/transformer is in the loop.
Honestly how could that even be proposed as an improvement in fidelity to the original signal when all it can possibly do is change it?
nt
try it! you know you want to!
"correcting" and re-correcting on each cycle. These newly-created errors eventually reach audio time scales and are heard as TIM distortion.
Such errors are perfectly acceptable when using feedback theory to control a potato chip fryer or an airliner autopilot system, as the steady state operation is what counts. Enough ears can testify, however, that the same theory may not be optimal for reproducing transient musical signals in the most pleasing manner.
I can't argue with your subjective impressions so we can agree to disagree...
try it! you know you want to!
Purifying amps squeeze the life out of it. I'll take an Audio Note amp over a Lamm Industries amp any day. Their P-2, class A, zero feedback PP amp (about $3000, the last time i looked) compares very well on my $2400 pair of Tonian Labs speakers to tube and SS amps at much higher prices.
Have you heard the Lamm ML2? It is really good..far better than a low end Audio Note like the P2. Once you get up to the Kegon level though it is a closer fight.
I agree about the different levels, although the P-2 PP is a bargain. I don't care for the sound from the Lamm amps at all. No magic.
For the Lamm hybrids I would agree...I would not agree though for their all tube models.
An amp can not "purify" or remove distortion from the signal, it can only add non-musical distortion.
try it! you know you want to!
Try to keep up please.
The SETs add less harmful distortion then SS amps with "low THD", even if they have a higher percentage number.
That is why there is the weighting schemes that Morricab was referring to.
"Low THD" amps already have all kinds of higher odd ordered distortion from the get go.
That is why SETs have the advantage, because they have predominate low even order harmonics that do not compound to the degree of the typical SS amp.
Adding "non-musical distortion" does remove good distortion from the material, it's a proven fact.
Before you ask me to prove it, I suggest looking into RF amplifiers where these phenomenon are encountered on a regular basis.
With your SS gear, you are hearing the cancelling effects that create the harsh tones, not necessarily are you hearing distortion directly.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
If you like distortion, of any sort, that is your own personal preference, and you are talking about personal preference when you say some types of distortion or distributions of distortion are "better" than others. Since it is personal preference, you can't make generalizations about what is "best".
And, just because an amp produces what some opine as "bad" distortion, it is meaningless in any case if it is below audibility, which it is in many high performance amplifiers.
SETs may have some advantages, but truth to the signal is not one of them.
I'm not hearing anything harsh from my amp. And since the distortion it produces is at or below the threshold of audibility, it isn't coloring the sound like so many tube amps.
try it! you know you want to!
"If you like distortion, of any sort, that is your own personal preference, and you are talking about personal preference when you say some types of distortion or distributions of distortion are "better" than others. Since it is personal preference, you can't make generalizations about what is "best"."
-No, you are the one who likes distortion! That is why you like that hockey puck!
"And, just because an amp produces what some opine as "bad" distortion, it is meaningless in any case if it is below audibility, which it is in many high performance amplifiers."
-It is not inaudible, if it were, your puck would sound more like a SET!
"SETs may have some advantages, but truth to the signal is not one of them."
-A reasonably design SET is more truthful to the signal then anything SS!
"I'm not hearing anything harsh from my amp. And since the distortion it produces is at or below the threshold of audibility, it isn't coloring the sound like so many tube amps."
-You got it backwards kid, you are the one hearing distortion, your amplifier is the one colouring the sound in a negative way, not the SET!
A reasonably designed SET has less detrimental colourations then anything else, that is the point!
The "colouration" that some hacks claim to be from tube amps is actually the unmolested sounds coming from the source material!
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Virtually all of the sort of amps favored by Morricab have have high levels of 2nd order distortion, especially at high frequencies and higher output levels.
You might be comparing SETs with 2% or higher 2nd order distortion versus SS or class D amps with .01% or less Total HD. Assuming you think the SETs sound better -- which might be purely personal preference that not everybody shares -- it needs to proven that it's the vanishingly low high-order rather than high 2nd that is making the SET sound "better".
I love the music of Dmitri Shostakovich
Actually Keith Howard showed with a rather clever test that ALL distortion is worse than the undistorted signal BUT that ones that follow the pattern that would be least audible to humans are less offensive.
So, there is no such thing as "good" distortion...it is all bad BUT it has been shown convincingly that some types are MUCH worse sounding than others. THere is no debate that high order harmonics should be avoided and YET go look at measurements and you will see that very very very few amps successfully avoid them.
It is about minimizing audibility and this is where psychoacoustic research is valuable in guiding how to design amps in this era where we have NO linear amplifying devices.
.
Have Fun and Enjoy the Music
"Still Working the Problem"
"Virtually all of the sort of amps favored by Morricab have have high levels of 2nd order distortion, especially at high frequencies and higher output levels."
-This makes sense and correlates well with what Morricab was stating.
High levels of 2nd does not kill the treble like low levels of high order.
Simply because 2nd is a much lower frequency, there will be much less nulling and peaking going on that ruins the treble. (Intermodulation)
"You might be comparing SETs with 2% or higher 2nd order distortion versus SS or class D amps with .01% or less Total HD. Assuming you think the SETs sound better -- which might be purely personal preference that not everybody shares -- it needs to proven that it's the vanishingly low high-order rather than high 2nd that is making the SET sound "better"."
-I am not sure who this part is directed to, but I tried to sum it up in my post before this one.
It is physics that proves that "vanishingly low high-order rather than high 2nd that is making the SET sound "better"".
As mention previously, these sidebands are encountered all the time when dealing with RF.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
And by the way, physics doesn't have anything to do with what sounds "better" or everyone would have a SET.
try it! you know you want to!
"And by the way, physics doesn't have anything to do with what sounds "better" or everyone would have a SET."-Yes it does, it has everything to do with it.
Maybe you can go out to your yard and clump some dirt and sticks together to make an amplifier, for the rest of us, physics is needed.What sounds "best" is the amp that doesn't really have a "sound", I want to hear the music, not the amplifier!
"At what level are these sidebands inaudible?"
-When there isn't any! The human ear is very sensitive!
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/19/15
Yes, the human ear is "very sensitive", but I expected something based on "physics" from you as surely you are aware that the human ear is not infinitely "sensitive".
Sure, physics is needed to make an amp. It has nothing to do with subjective judgments, which are what you are making.
try it! you know you want to!
You are confusing distortion percentage with a volume level, a low percentage does not render it inaudible, it will affect the subtle textures that makes things sound real.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
OK smart ass, 0.000% sidebands is inaudible and will not alter the magnitude of frequencies in the source material.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
So much for physics and rational discussion....
try it! you know you want to!
How so?
Please explain how you arrived at this conclusion?
△ᴉʇɐuᴉɯnllI oᴉpn∀△
there is no level at which sidebands are inaudible. That means the ear has infinite sensitivity. LOL...
try it! you know you want to!
... It's a few percentage of 2nd order.One thing discovered by Pythagoras 2500 years ago was that high-order harmonics sounded bad -- harsh, discordant. Nobody is really arguing with Morricab and his ilk that high-order sounds good , only that there is some level where it's inaudible.
But other thing that Pythagoras discovered way back then was that 2nd and even 3rd order made the sound mellower and richer. The fact that Morri et al. refuse to admit is that the style of amp they prefer sounds "good" because it has 2nd order, not because it doesn't have immeasurable amounts of high-order.
I love the music of Dmitri Shostakovich
Edits: 09/20/15
If you look at the measurements of many good SETs you will see that the THD is usually well below 1% at 1 watt and continues to decrease logarithmically as you drop down lower in power and increase logarithmically as you go up in power (looks like a straight line on the usual Log/log plots presented in Stereophile and Soundstage).
What this means is this, not only is the content predominantly low order harmonics at low power even that is very small and completely inaudible. Plus there are no nasty harmonics to interfere.
If you use reasonably sensitive speakers then you will never be in a region where you are at 2 or 3% distortion except on music peaks where the loudness of the music works against the audibility of the distortion anyway.
Note that a lot of amps actually have higher relative distortion at low power than at higher power...this is probably because of residual crossover distortion or some other level independent type distortion.
If the amps in question made 3% 2nd order at 1 watt then you would have a good point...as such they usually are more like 0.5% at this power, which is completely inaudible.
One thing my "ilk" can do that seems to be lacking by many on this forum is the ability to read and interpret the data that is available and put it in context of what various authors are saying about distortion and audibility.
All distortion at some level does damage to the signal...2nd and 3rd order are no different...just more consonant with music than the higher orders. Also, it is clear that IMD is not so consonant with music (even 2nd and 3rd order) and it is what Nelson Pass calls in his paper on distortion "The elephant in the room".
Again, Keith Howard demonstrated that no added distortion sounded better than any pattern he tried BUT the montonic pattern was the least objectionable.
So an SET's is a perfect 1watt amp at 8 ohm only ... :)
I had asked before but will do so again , is there any SS class-A biased amps with high distortion at 1 watt...?
Better than imperfect at any power and any load I would say...not that they are as limited as you imply.
As to your query, go look and let me know. Howver, I thought it was rather clear that absoute amount of distortion, particularly at 1 watt is not really what we are talking about here, are we??
Just to quickly jump in here...
Morricab cited references that ALL types of distortion are detrimental.
In order to have virtually no offensive higher order harmonics, one has to accept a little bit of second.
Which again, when weighted is not really discernible because it blends so well with the intended source material, it becomes for all intents and purposes inaudible if kept reasonably low.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
that have harmonic distortion of all harmonics, not just the 2nd, below audibility....
try it! you know you want to!
when it is simply a matter of personal preference?We keep being told how studies have "proven" humans "prefer" certain distortion profiles as a rationale for declaring certain topologies or amp types are "best". Certainly the results of any such study weren't 100% thus there is always room for tastes to differ.
Regardless of what any study has shown, isn't the simple fact that there are so many amps of so many different types successful in the market place proof that the premise that there is a "best" fallacious?
try it! you know you want to!
Edits: 09/19/15
"Regardless of what any study has shown, isn't the simple fact that there are so many amps of so many different types successful in the market place proof that the premise that there is a "best" fallacious?"
In a way, yes but only because of so many different goals.
If the goal is to have the sound coming from the speakers of a playback system sound the way the music sounded in the recording studio then a person first needs to know what real instruments actually sound like.
Not everyone does, not everyone cares. Most people just want a system that "sounds good to them", whatever that means.
So, in the end, the answer to your question is no.
Having "many different types successful in the market place" only proves how many different goals people have.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
nt
try it! you know you want to!
""goals", preferences, the same thing"No, they are not the same thing.
If the goal is for the playback to sound the way it really sounded....that is very different than simply "I want it to sound good to me".
Many times I have made actually improvements in my system only to have the initial reaction of "I don't like it".
I had become accustomed to the sound of my system even though it was wrong. That had become my "preference".
Listening again, with my objective goal in mind, I had to admit that the piano sounded more like a real piano and the acoustic guitar sounded more like a acoustic guitar, etc.
"..clearly not everyone agrees on what is best"Yes, but only because of their ignorance (lack of knowledge of what real instruments sound like and/or an abandonment of the real goal).
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/19/15
It is well known fact that our senses are often and easily fooled. Stereo is just one such tech that relies on that fact. Not everyone agrees on what sounds "real".
Those whose interpretations differ from your concept of what constitutes "real sound" are "ignorant"? WOW....no point discussing anything with you, God....
try it! you know you want to!
Edits: 09/19/15
"Not everyone agrees on what sounds "real"."
Some people don't like the sound of a real acoustic instrument even in the presents of. But that's not the same thing as disagreeing.
and therein lies the problem. The misunderstanding of the goal.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
listening to a recording and saying amp a is a more true to life sound versus amp b and saying your opinion is "more" correct than someone else's. And saying those that disagree with you are ignorant.
try it! you know you want to!
If I was the recording engineer and heard with my own ears both the live instruments and the live mic feed and I was the one who made the decisions as to how close to or how far away from the actual sound of the instruments the recording was going to be, don't you think I might be in a better position to judge?
All opinions are not equal.
Get over it!
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
nt
try it! you know you want to!
"Get over what?"
Get over the fact that all opinions are not equal.
"Have you been the re on every recording made?"
No but I have been on enough to have more than just an unsupported opinion.
How many have you been on?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
and I have heard enough live music to be comfortable with my ability to judge what does and doesn't sound like live music. I don't have to be a professional chef to know what I like to eat either...
try it! you know you want to!
"All opinions are not equal."
I agree with you. People who spend their entire life listening to recordings and not making any are, at best, second class audiophiles. When it comes to disagreement as to what sound's right and what doesn't, I take this experience into consideration whenever possible.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
nt
try it! you know you want to!
It's not listening to recordings that counts, it's listen to unamplified real instruments.
And yes, even those who have don't always agree but they each have a real point of reference so at least they're in a position to argue.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
nt
try it! you know you want to!
Yes and their arguments are worth listening to and trying to learn from.
From what I can tell, your argument is not.
You say that listing your system it not relevant to the discussion but it is.
It would give some insight into where you're coming from.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
You don't need to know my system to have this discussion any more than I need to know your system. We aren't talking system specific issues, we are talking about personal preferences. Yes, even your engineers who "spend their entire life listening to recordings" don't agree. That's my point. It's subjective and people don't all agree on matters of taste and interpretation.
try it! you know you want to!
"It's subjective and people don't all agree on matters of taste and interpretation."
Then why do you keep arguing for amplifiers with, in your words, inaudible distortion?
What does it matter if all that matters is each person's own opinion?
If that were the case then there is no reason for discussion at all.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
"People who spend their entire life listening to recordings and not making any are, at best, second class audiophiles."
I wouldn't call them that.
I would just say that they are ignorant.
Ignorant is not a pejorative term (at least I don't intend it to be), just descriptive.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Thats plain silly , philes dont have to make their own recordings , there's always live music and regardless , a hi fi system is for enjoyment not science research or to be used for telemetry , so they will always choose what pleases them , for some its the glow of toobs , others is amps small enuff to fitin your pocket ... :)
Recordings for sure, if designing and or reviewing ...
Edits: 09/19/15
I don't disagree with what you have said in the spirit in which you said it but......
An audiophile is a person enthusiastic about high-fidelity sound reproduction.
So audiophiles seek out excellent recordings and strive for a playback system that will have a high degree of fidelity to that recording.
In the audiophile's mind it's more important than "telemetry" and takes a lot of "science research".
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
nt
try it! you know you want to!
Well, on that count I disagree with Nelson.
For the casual listener it is just entertainment but for the serious audiophile it's a life long journey striving for unobtainable perfection.
I have to say there is a lot of entertainment along the way.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
"As I said at the beginning, this has been an interesting amplifier to develop,largely because it has contributed to my depth of knowledge as to what techniques make for a good sounding amplifier. Of course this is a subjective thing, and no amplifier is the best for all listeners and situations."
try it! you know you want to!
nt
try it! you know you want to!
.
Have Fun and Enjoy the Music
"Still Working the Problem"
I believe in freedom of choice without insult and innuendo. My issue is with claims that a certain amp or amp topology is "best" or "better" than mine, or yours, for that matter. Personally, I couldn't care less what others like, but I don't appreciate the arrogance shown in dictating matters of taste. Putting down what others find excellent because it doesn't fit a model, a flawed study, or using measurements when it is convenient to an argument, but claiming they are irrelevant when not, etc., is propaganda, plain and simple.
How can there possibly be a "best" amp, i.e., one that does everything "best" in all systems, in all rooms, to all listener's complete satisfaction. Nothing is perfect. Each topology has it's strengths and weaknesses. We each consider those and based on our own preferences and ranking by importance of features, make a choice. The only person whose opinion matters is the one buying the equipment. It is ludicrous to be told that there is something inferior with your choice if you don't agree with some claimed "best".
Additionally, I know of no study of human preferences that has had unanimous results, that is, an audio study in which a group of people were asked for their subjective preference and had 100% agreement. You can't use a study based on subjective selection criteria to then infer something objective about those preferences. In other words, let's say someone did a study to see if there were certain types or patterns of distortion that were objectionable, or less offensive, or whatever. And 90 out of 100 people tested choose even ordered, descending harmonic distortion as agreeable, or least offensive, or whatever. That still leaves 10% with a different take. Are they "wrong"? You then take these results and say any amp that doesn't have this distortion pattern is fundamentally "flawed" or not as "good" as one that has the preferred pattern. Since no amp is perfect, it can't be anything but different! How can any value judgment be valid?
But you can argue objective performance. So when an amp is said to be "best", the only way that can be argued is through objective parameters, i.e., specs. Thus, I have asked for a spec comparison. We then usually get the "measurements don't tell the story". Well, no, they don't tell the subjective story, but again, that isn't open to debate. If a pet amp topology is "best", it should surely also measure well. But measurements are too simple to be accurate. Well, if an amp can't preform with simple signals, how are we to believe it does better with complex ones?
When an amp is putting out distortion at 5% and has harmonics at -40db, it isn't simply reproducing "live instruments" alone any more....it's an effects box. To each his own, I have no problem with that, again, that's subjective taste. But don't tell me an amp with clearly audible distortion is "best" or "better" in some objective way when there are those at 0.005% and -110dB down across all harmonics.
try it! you know you want to!
> But you can argue objective performance. So when an amp is said to be "best", the only way that can be argued is through objective parameters, i.e., specs. Thus, I have asked for a spec comparison. We then usually get the "measurements don't tell the story".>So which particular amp is the best in terms of measurements - if you can't tell us a specific one and show us why compared to the second best then your whole argument is just made up and in audio terms is totally meaningless.
If not the two best amps, then just the two best you know of for comparison - by two different manufacturers.
Edits: 09/19/15 09/19/15 09/20/15
subjectively or objectively. I have said that objectively, its specs are hard to beat and better in general than those who claim their tube amp is objectively superior.I have also said that the claims some have made about their tube amp being more accurate and better at recreating the sound of "live music" is false objectively because their tube amp is producing audible distortion. It is commonly said and many studies have shown that 1% THD is audible and that on average human hearing is capable of hearing to -80dB. Most tube amps will produce thd at or above 1% and many will have harmonics at greater than -80dB. Additionally, SN ratio, output impedance, and frequency response versus load are often poor or cause issues.
I have posted a link to the specs of my amp several times. I have put up. Perhaps you should too if you want to argue objectively. Have you figured out the difference yet between subjective and objective?
try it! you know you want to!
Edits: 09/20/15 09/20/15
The study of psycho-acoustics is not a beauty contest (an A/B listening test).
It's a scientific study into the ear brain mechanism not accomplished by taking a poll.
It is that and physics that lead us away from non-linear devices, push pull and feedback.
Anyway, it's been fun. :-)
I would listen to your amp in my system anytime you want to bring it over.
With my speakers I only use a fraction of a watt and many SS designs have their highest harmonic distortion % output at those low output levels.
I have no idea if that's true for your amplifiers.
Take care,
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Which class -A SS amp has a lot of distortion at 1 watt ....
No, I think it's Class B or Class A/B SS amps that have that problem but I don't think the problem extends all the way to 1 watt.
Is the N-Core amp Class A?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
no, class d....
try it! you know you want to!
So, if you know, is there the equivalent of crossover distortion in a Class D amplifier?
I just read the IR pdf about Class D amplifiers and there seems to be, having to do with switching and dead time.
The chart I'm looking at shows that the HD starts higher and doesn't drop to minimum until 10 watts output.
After reading that pdf it seems that Class D amplifiers are held together with a wing and a prayer.
I would really like to hear one of these things.
Like CD, once you understand how PCM works it's amazing that they sound as good as they do.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
"Note: THD+N includes noise.
Noise (mainly thermal noise from resistors) dominates below 10W. Since the noise level is constant and absolute its amplitude relative to the test signal level, expressed in percents, is higher for lower signal levels. This in no way implies that distortion performance has an optimum at 10W but that at lower powers it is completely unmeasurable amongst the (very low) noise. This is why distortion spectra are only shown for high power levels where any distortion of note exists. "First Watt" performance is, in fact, first rate. "
try it! you know you want to!
I was reading the International Rectifier pdf.
The above is from the N-Core pdf that you linked and no, I don't see the note.
I searched the pdf for "Note: THD+N includes noise" and came up blank.
The above is not THD+N to start with.
BTW not that it matters but it looks like this one bottoms out at 6 watts vs. the 10 watts from the IR pdf.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
http://www.hypex.nl/docs/NC400_datasheet.pdf
try it! you know you want to!
I was looking at the nc1200 datasheet that you linked in this post,
http://www.audioasylum.com/forums/amp/messages/20/208394.html
The only thing that matters is how it sounds. Bring of over and we'll listen to it!
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
...is how it sounds.
Yep.
I guess you have now backed down from your objective claims.
try it! you know you want to!
do you really think all opinions are equal?
would you use a surgeon with no experience?
interpretations based on what?
actually hearing and studying the sound of real instruments?
or just hearing different stereos?
I didn't say anyone was stupid, just ignorant.
there's a big difference between ignorant and stupid.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Ignorance is curable- stupid is forever
must be ignorant is indeed arrogant and simply wrong. Trained musicians don't always agree. How do you know someone else's level of training or experience? Who are you to dictate your interpretation?
try it! you know you want to!
When you walk from the studio to the control room, the mic feed either sounds like the instruments in the studio or it doesn't.
Educated people present and taking that walk do not disagree.
The mic feed either sounds like the instruments or it doesn't.
How many times have you been in a recording studio with real players playing real instruments while being the engineer who is setting the mics and making the decision whether or not the true sound of those instruments is being captured?
Never.
Yeah, I thought so.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
nt
try it! you know you want to!
No you don't but it's a matter of degrees.
Your opinion is not as reliable as the opinion of a person that has spent years professionally studying the sound of live instruments. Correct?
Again you wouldn't hire a surgeon with no experience to cut you open, would you?
All I trying to get across to you is that not all opinions are equal.
You do agree with that, don't you?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I don't buy on reviews even though no doubt most professional reviewers have heard more gear than I have.
Again, audio isn't brain surgery. You are confusing the subjective with the objective. When it comes to matters of taste, no one knows what I like better than me....
try it! you know you want to!
...apparently you don't understand the scientific method.
Objective is observational - how does this sound differ from live, unamplified music?
Experts with well developed critical listening skills and knowledge of live music would agree.
Subjective is opinion - how do I like the way it sounds?
Everyone has different priorities in the way music is reproduced.
If measurements correlate to the objective observations, then they have relevance. If not, you continue to look for other measurements which do.
for anyone who actually believes there are amplifiers with "inaudible distortion". :)
Objective is metrics- how does something measure. How something sounds "different", objectively, requires a physical measurement, rather than someone's opinion, which is simply subjective, regardless of who makes the observation. Why? Because measurements are not subject to bias, tastes, or other foibles of human perception. You can't argue with an oscilloscope. A SN ratio is a defined quantity. Your claim of what constitutes a "better" amp, without any defined physical metrics, is simply your subjective opinion. And we all have those...
Experts don't agree. That's the whole point. Human perceptions differ, tastes differ.
Some people like distortion, some don't. Some prefer signal fidelity, some want what they perceive to be a "live sound", which is simply their conception of a live sound, as there is no one "live sound".
Still want to compare specs?
try it! you know you want to!
...here is the part you are missing - for a measurement to be RELEVANT it has to be correlated to the goal and purpose of the product.
If the goal of an audio amplifier were to produce the lowest THD+N, you would be correct.
But it isn't.
The goal here is to reproduce music as realistically as possible through loudspeakers.
You cannot determine that with measurements unless they correlate to the result - and you cannot judge that without objective, observational listening.
Which is what JA attempts to do in Stereophile with his suite of measurements.
Otherwise the objective measurement "watts per pound" would be just as important.
Better go back and take a basic science class.
I would have thought you understood that I am referring to measurements related to the goal of an amp, which for most designers, is a wire with gain.Your goal is some nebulous, undefined, subjective "as realistically as possible", which means different things to different people and is completely and unarguably, without any definable metric, SUBJECTIVE. If you can't comprehend that basic concept, you are the one lacking in basic understanding.
There is no such thing as "objective, observational listening". What exactly is "observational listening"? LOL...Listening, by definition, is a subjective act as you will always find people who will differ on what was "heard", never mind the established fact that human senses are prone to bias and other error.
You arguments are flawed, as is your understanding of the topic. Enough, I am tired of you and your demonstrated inability to comprehend the difference between subjective and objective and the implications of each with regards to claims about amp performance.
try it! you know you want to!
Edits: 09/20/15
...since there IS NO SUCH THING as a straight wire with gain, how do you know how one amplifier's deviations from that goal affect the music as opposed to another amp's deviations?
Which reproduces music more "accurately"? One of the two must.
It is NOT POSSIBLE to find out JUST with measurements.
Observations of trained critical listeners are not "subjective" any more than is your ability to identify your wife's voice on the telephone.
And of course you are tired of my comments because you KNOW my logic and reasoning are correct.
Which makes you WRONG.
Music reproduction is the ultimate goal, not trading off one bench measurement for another, and you cannot determine the success or failure of a design WITHOUT LISTENING to the result.
"You are confusing the subjective with the objective"
No, I think you are.
Do you have any understand of physics or electronics?
We have to use our subjective interpretation of our senses to try to determine if we are meeting our objective goals.
Whenever I make a change to my system, that physics (the type that morricab was talking about in his original post "I would say nearly all amplifier designs are conceptually WRONG!") tells me will be an objective improvement, it ends up being a subjective one as well.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
nt
try it! you know you want to!
Well once again, the goal of the hobby is expressed in it's name. Hi-Fi.
A high degree of truthfulness to the original.
I believe if we had a playback system (this would include the room and all aspects of the system) and a recording (both of which being deemed perfect in every way by the good Lord Himself) a lot of people wouldn't like it because that's not what their looking for.
I do not have a problem with that. People can listen to whatever they want to and enjoy whatever sound (no matter how far away from real it is) they want to....just don't call it Hi-Fi.
If it's Hi-Fi you're after then there are rules (as pointed out by morricab) prescribed by science and the study of psycho-acoustics that need to be followed.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
How do you determine how close you are to that goal of high fidelity, whatever it may be?There is only one way to reach that goal?
If your audio experts can't agree, then clearly there is no unique solution.
try it! you know you want to!
Edits: 09/19/15
"What is your definition of high fidelity?"
I just gave you THE definition of Hi-Fi. It's not exclusively mine.
" "Original" what?"
Sound of the instrument. In a recording that would be the sound of the instrument at the mic position.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
A high degree of "truthfulness" to the original? That is subjective goal unless you have a metric to define "truthfulness". Not everyone will agree on what is most "truthful" to the original.
The "sound" of the instrument? Another subjective goal. Unless you were there at the mike feed, it's impossible to know with certainty what the sound was exactly, and even two people who were there may not necessarily agree because not everyone interprets sensory input identically. And that isn't even touching on the fact that not all instruments of the same kind even sound the same!
That's the problem with subjective goals. There is no objective way to prove when you have reached them, or no absolute reference to judge exactly how close you are. All you can do is give your opinion, and as we know, even seasoned experts with all the experience in the world may and do disagree. There is no closed solution.
try it! you know you want to!
"Unless you were there at the mike feed"
It's "mic position" and I was, many times.
With the likes of Dennis Green (RIP), Roger Kellaway https://en.wikipedia.org/wiki/Roger_Kellaway and John Ondrasik (Five For Fighting) playing our 9' Baldwin concert grand piano.
Jim Capaldi's (RIP) drum set and congas.
Johm McEuen's (Nitty Gritty Dirt Band) banjo and acoustic guitar.
Kenny Loggins' voice.
Dave Mason's voice and acoustic guitar.
Chris Hillman's (The Birds, The Flying Burrito Brothers, Mcguinn Clark and Hillman, The Desert Rose Band) guitar and voice.
Jonathan McEuen's voice and martin D-28 acoustic guitar.
Phil Salazar's fiddle.
Ann Kerry Ford's (wife of Robben Ford and Broadway singer) voice.
I can do this all night but it won't convince you of anything so what's the point?
I can see that this is going no where.
Why don't you just bring your amp over and we'll give it a listen?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
what I doubt is that everyone would share your interpretation of that experience.
And no, I won't be swayed that your experience and opinion of those experiences is universal truth.
Ever see the film Rashomon?
Anyway, I have a feeling you are no where close or I would be happy to give you a listen. I suggest trying to find someone local with an ncore based amp and have at it....In the meantime, check out the specs. I think you will find them interesting.
try it! you know you want to!
"Isn't "high fidelity SET" an oxymoron?"-No, but High Fidelity Class D is.
"How do you determine how close you are to that goal of high fidelity, whatever it may be?"
-See post #1.
Can you tick any of those boxes?
My Garg0yle 2A3 DC's hit 6 out of 7 with a quick glance, 7 out of 7 with a verifying measurement.
( 7) Flat distortion profile vs. frequency (most amps rise in the highs or bass or both). )
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/19/15
http://www.hypex.nl/docs/NC1200_datasheet.pdfAs for the "check list", can you point me to some documentation or research that proves those factors positively correlate universally with subjective preferences? Or even objective measurements? Of course I am referring to normal human preferences, not those with infinite hearing sensitivity....
try it! you know you want to!
Edits: 09/19/15
"As for the "check list", can you point me to some documentation or research that proves those factors positively correlate universally with subjective preferences? "
-I could, but obviously you wouldn't read it anyways, so what's the point.
I recommend you re-read what has been posted so far before you try anything more advanced.
You know, I don't consider myself a smart man, however I was chosen as a global community teachers assistant for the Massachusetts Institute of Technology's circuits and electronics course in 2013.
This was not based on my skill set per se, but on my ability to explain electronics in a different way so that people new to the field from across the world could understand.
That being said, I am qualified to say, that you are one of the most stubborn people in the world.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
or leave me alone...
try it! you know you want to!
I understand, you probably feel silly now arguing with a guy that learned electronics from MIT.
Can't blame you there.
It is time that you start providing information that proves the superiority of your gear instead.
I don't have anything else to say on the matter at this point in time.
I really only stayed in this long to lend credence in regards to what Morricab was talking about.
Perhaps in the future there will be an interesting thread that explains as to why we as humans have evolved over thousands of years to find certain harmonics distressful.
I don't want to spoil it for you, but I'm sure some here can already guess which typologies sound distressful. ;)
For now, carry on as you were.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
You're the one claiming the objective superiority of your SET and how it "checks all the boxes" and how class d is "low fi". I call your bluff and offer you the chance to make your case and you fold.
I'm guessing you had a look at the ncore specs and you are the one feeling a little silly now...
try it! you know you want to!
I had the opportunity to experience one of the Telarc recordings of the Atlanta Symphony Orchestra. After many takes, Shaw would review the results downstairs and critique the performance.
Jack Renner is a sharp guy.
I'm not saying I have the experience or the trained ears of a Robert Shaw or a Jack Renner but 15 years in the recording industry did teach me a thing or two.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
That is totally incorrect, everyone who is into "High Fidelity" has the same goals.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
When I first became interested in "hi-fi" back in the early '70s, people were interested in just that: high fidelity.
Today the goal of many is the euphonic, not the high-fidelity.
I love the music of Dmitri Shostakovich
Euphonic:
adjective
denoting or relating to euphony; pleasing to the ear
God forbid - unless my music sounds UNPLEASING I'm not happy! Bleed eardrums, bleed!
----Feanor
why do audiophile are so depressing!
Why flog yourself? If it sounds good why does that mean "euphonic"? Do you want flat, grey and sterile to convince yourself it is "accurate"? Do you hear that when you go to a live unamplified concert (do you go?)
I went last Friday to hear Beethoven piano and organ concertos (number 1 and number 4) in a Church in Zurich. It was rich and full and dynamic sounding...you might say "Euphonic" (I know anyone with a Magico + Soulution system would think so if it was from a recording and not the real thing).
Do you really think all the recordings are so devoid of life?
... then that's the way it ought to be reproduced -- it's no the role of playback to "correct" the recording.
See my comments on "live sound" in my post below.
I love the music of Dmitri Shostakovich
And no one (at least I am not) proposing to "correct" for anything.
There are far fewer really poor recordings (outside of pop/rock that is) than people realize.
Even though I do not agree with all that Audio Note, UK, has to say, their discussion that a system should give you maximum contrast from recording to recording is pretty informative. Recordings have a HUGE variety of different sounds and if your system in any way homogenizes them then it is somehow wrong. So, if you are finding a lot of recordings sound flat, grey and boring way...beware that something is likely wrong.
I have made quite a number live recordings, have you? I know live sound intimately from years of exposure and recording. The sound I got is never grey or flat or sterile...even when using DAT tape. I still use some as reference material.
I disagree, that is just another one of those old statements SS fans say to disparage SET fans. Ad nauseam
If anybody out there reading this is chasing "euphonic" effects, stand now and be counted.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
"If anybody out there reading this is chasing "euphonic" effects, stand now and be counted."That's the thing.
There are some who are chasing "euphonic" effects, know the difference and freely admit it.
I have no problem with that. Who the hell am I to dictate what someone else should want to listen to.
On the other hand there are those who think they are chasing the truth, but don't know what the truth is and in fact like "euphonic" effects (or the presents of high orders of HD causing what some think is "speed" etc..) but won't admit it (or I should say, can't admit it because they just don't know better).
This is why I have said that it is very important for everyone in this hobby to take the time to get intimately familiar with the sound of real acoustic instruments.
Otherwise we will never move the SOTA forward. We, instead, will just keep arguing about opinions.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/19/15
Heard some nice Beethoven piano and organ concerts last Friday in nice Church. I am sure many hear would call that sound "Euphonic" if they heard it coming out of their stereo systems :).
These guys must really think most recordings are crap to believe that the flat, grey and lifeless sound they hear is "accurate".
There are millions of live sounds; they depend on:
= The venue
= Your seat in the venue
= The musicians position in the venue
= The individual instruments used
= The playing style of the musicians
= The temperature and humidity
= ... a probably a few other factors.
Any "typical" live sound that an individual might imagine is highly subjective and affected by preference.
I love the music of Dmitri Shostakovich
Let's clarify a bit, shall we?
I am referring to A) Live UNamplified music
B) Clearly the position you sit will affect the final outcome...but you still are unlikely to confuse the live sound (wherever you sit) with recorded and played back sound...you agree?
C) Again, individual instruments will for sure affect the original sound but if a violinist uses a Strad and then switches to a cheap modern students violin you aren't going to say suddenly "Geez now he sounds just like a recording!!" are you? It still sounds LIVE, regardless of the drop or gain in quality
D) Whether the musicians are great or they blow won't impact whether you think the performance is LIVE or not. Whether you like their performance or not is also irrelevant to the issue of "liveness".
Seriously, I don't think you completely don't understand the difference between the real thing and a recorded and played back event.
All the live examples above are still not likely to be mistaken for a recorded and played back version of that event. This is the main point that you miss.
You keep talking about different kinds of live as if they could be mistaken for a recording and that just won't be the case in nearly all circumstances.
I hear people talk all the time that it is like wine tasting...except that they are simply wrong and it is not at all like wine tasting. Wine tasting is the direct "live" event, just like going to hear real musicians play. The character, flavor etc. is different from wine to wine just as from performance to performance. Recording and playback is now a step removed from the real thing and the goal is get as much of that real thing captured for all time. There is NO analog for wine tasting (you can't smell or taste a picture of a glass of wine, for example) or food tasting for that matter. There are visual analogs but no one is saying that a flat TV picture would fool someone into beliving its real. Maybe if they perfect hologram TV they can open this discussion...
No dispute.
I love the music of Dmitri Shostakovich
Literally speaking you are correct...however, that was not really the point...
Every recording should sound different , because they are , its the one thing really common with class-D amps , they do not deliver this varying contrast with recordings as well as Class A or AB amplifiers , Well , at least the ones i have heard so far .
They do capture live thou ....
Also, no amp is perfect, they all have strengths and weaknesses. That's a fact. Choosing an amp involves subjectively ranking which strengths are more important to you, which weaknesses least important. Add to this the fact that all amps are part of a system, and not all amps have the same strengths and weaknesses in all systems, and the whole hypothesis crumbles.
And we don't even need to address the faulty hypothesis that all live unamped music sounds the same to all people.
try it! you know you want to!
"They do capture live thou .... "
Live...but the same!! Things that make you go hmmm....
the make of the instruments used, and the season when the performance takes place...
Ever see the movie Rashomon? I think that explains the subjective nature of human perception quite elegantly.
try it! you know you want to!
nt
try it! you know you want to!
"Music is distortion "
That is a excellent way to put it.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
It isn't nearly as simple as you put it.
Did you know that a single ended amp can't even do a decent job of reproducing a simple sine wave? And this problem is inherent to a single ended circuit. It can't be fixed. When a sine wave is reproduced by a single ended amplifier the distance from the 0 voltage point to the top of the positive wave is greater than the distance to the bottom of the sine wave. The negative half of the wave essentially is cropped relative to the positive half. It's a significant factor in the large amounts of 'pretty' second harmonic distortion in all single ended amps.
There is no perfect format. All amps are compromised in different ways. But at this point we know that while 'nice' a single ended design will never be a final solution.
Funny, I wouldn't have said I put it simply at all. If you start to add up my points you will see that it is complex enough that very few have done it really correctly.
WHat you are saying is obvious because that is where the 2nd order distortion comes from...it is asymmetric. However, it is also dependent on the load line and the power output...nevermind that as long as you don't make a lot of IMD 2nd order harmonic is inaudible up to several % even with a pure tone. Read what's out there on psychoacoustics.
Obviously until a truly linear device is invented there can be no perfection...until then though there is definitely better and worse.
When accounted for, this is pretty minor.
I guess you aren't aware that triodes are the most linear voltage amplifying devices available?Just to clarify, the "pretty" second harmonic distortion, is actually the source material being more realistically conveyed.
What you are hearing is the lack of detrimental distortion.It's not that SETs sound "rich" per se, it's that other typologies sound cold.
The additional harmonic content from other typologies suffers more from spectral regrowth. (Harmonic distortions of harmonic distortions) It is these compounding distortions that null out and interact some of the intended material, rendering it cold and harsh sounding.
It gets even worse when the input signal is increased.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/18/15
Sounds rich is correct. It always sounds rich because of high 2nd harmonic. What I find more important is that SE can't even do a simple sine wave correctly much less a complex music wave form. This means, since it is the nature of an SE circuit, that it can NEVER be correct. Perhaps other formats can be since this simple wave form distortion does not seem to be endemic to push/pull although, I admit, that there may be other problems that are unsolvable in push/pull.
And yes I have known for decades that a triode is the most linear amplifying device. But I would use it in an amp that is push/pull all the way(except for a 1st stage transformer used for phase splitting) without negative feedback. Not perfect but much preferable by me to SE. And I could at least get some real power from such a configuration.
"Sounds rich is correct. It always sounds rich because of high 2nd harmonic. "
-While rich sounding amps have high 2nd, it is not the high 2nd directly that makes it sound rich.
"What I find more important is that SE can't even do a simple sine wave correctly much less a complex music wave form."
-While not perfect, it is still better then anything else available.
"And yes I have known for decades that a triode is the most linear amplifying device. But I would use it in an amp that is push/pull all the way(except for a 1st stage transformer used for phase splitting) without negative feedback. Not perfect but much preferable by me to SE. And I could at least get some real power from such a configuration."
-A triode in PP has the exact same non-linearity you are concerned about as the SE. PP does not change the transfer function of the tube.
All you have created is symmetry, not linearity.
Your configuration is suitable if you need the power, can't argue that, but realize you have created a worse situation then having a single SEnded triode .
△ᴉʇɐuᴉɯnllI oᴉpn∀△
As a friend said 'color me perfect'. You choose your color and I'll choose mine. But I'll take the amp that's more dynamic(at all levels) every time and it isn't an SE especially one with just a few watts which is almost every SE. And you'll choose another color. But they are at best just different and you have no way to substantiate your color is better except for your personal use. You haven't proven at all which is the 'correct' road to follow.
And at least a PP can do a single sine wave so the negative half looks like the positive half flipped.
"And at least a PP can do a single sine wave so the negative half looks like the positive half flipped."
Actually, it distorts them both equally...and you get 3rd harmonic plus others...
of course but that's the point an unsymmetrical sine wave is an awful reproduction. Besides the asymmetry implies overt non-linearity which according to some very knowledgeable designers is fundamental to reproduction. David Berning considers linearity fundamental.
nt
try it! you know you want to!
OK, show us a device that is more linear then a triode, I won't hold my breath.If you find something, I recommend you quickly patent it.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/19/15
You are correct about the tube but not the circuit. And some triodes are more linear than others. The fabled 300B is just very good. The 2A3 is more linear and I'm told the 45 more linear yet. The problem is power.
However a screen drive 509 or 519 is a very linear triode and a push/pull pair is capable of well over 200 watts. And on another front the old Sony VFETs are a very linear solid state triode and they don't need an output transformer. Their curves look like a 2A3 and you can get power out of them too.
As I mentioned in my post to start this thread...the problem may not be so much the device...although even the VFets and screen driven 509s are not as linear as a good DHT, but using it in push pull. So, Nelson's SIT amp might be the answer but even that, I am told, doesn't converge with DHTs. It is also power limited.
I got pretty close with my NAT Symbiosis, which was a Class A SE(T) hybrid. Input and driver were tubes and the output was a single big industrial MOSFET mounted on the bottom of a vertically mounted monster heatsink. It delivered a true 100 watts of Class A power with no negative feedback and had the tone of a nearly perfect SET and SS like bass control and drive. HOWEVER, it was still missing something that was difficult to pin down and in the end I preferred true SET amps over it. I wish I could find some measurement data on it but there seems to be none because it was probably close to ideal but missing in a key area.
In terms of imaging it was more like great SS than holographic 3d.
According to a friend who loved and used the 2A3 the Sony VFET curves looked about as good as a 2A3. And from a friend who made commercial amps a screen drive 519 did not just show decent triode curve but very good ones.
By the way one of my big questions in audio and you do it too is class A SET. What is a non class A audio amp? SET has to be class A in a classic analog amp. There's no other real option.
The problem with VFETs and SITs are what's available power wise. There's not enough call from audio for VFETs. I think big ones were used in TV power supplies in the 70s. Audio alone can't support manufacture. But if it could we'd have high power triode performance without transformers.
On your hybrid you didn't have triode output so I'm not surprised you didn't quite like the sound. A MOSFET isn't a triode device while a VFET is a solid state triode.
nt
try it! you know you want to!
As far as I can see you have just two things in THIS world - the picture of the electronic puck as your signature, and that cheesy commercial line from the '50s under it.
#7 distortion vs frequency
My amplifier is tubed, push pull with minimal feedback and was measured on a HP distortion analyzer....0.08%THD, 1 watt, at 1khz, standard parameters, frequency response 5hz-80khz +/- (0), and a gentle roll off of 3db at 100khz, makes perfect square waves at 5 hz, and makes rated power 70wpc at 20hz.
My amp measures similar to Conrad Johnson, Audio Research, (their transformers are even better out to 200k), Quicksilver, Music Reference, Pass Labs, Jeff Rowland and many other well engineered amplifiers.
The measurements I have seen on my amp are not in agreement with #7 which tells me the sampling number was small, and some of the well engineered, linear amps did not make it into the mix.
I would be cautious about reading too much into following a "checklist" of statistical requirements of an amplifier. Buy well engineered amplifiers, do your do-diligence, and enjoy the music. Just remember Yamaha once made a zero distortion amplifier....lasted a year be a use it sounded so bad
An amp that varies its distortion level with frequency will have sonic issues because what it is generating is not consistent and what is not consistent is what humans notice the most. The other problem is that invariably the content of that distortion is also changing and not just the relative level, which would be bad enough on its own.
"My amp measures similar to Conrad Johnson, Audio Research, (their transformers are even better out to 200k), Quicksilver, Music Reference, Pass Labs, Jeff Rowland and many other well engineered amplifiers. "
Engineered? I am not talking about the quality of the engineering...no doubt they are designed just fine with regard to the design goals.
I said CONCEPTUALLY wrong as in the whole basis for the design is flawed and based on flawed thinking about how an amp performs its job.
And more all the time with so many class D amps hitting the market? Is it JUST that they are cheaper to build or what? (After all, Lamm is on the pricey in absolute terms, not to mention $$/watt.)More to the point, why is it that so many people are impressed by them? Don't they know about Crowhurst, Cheever, Geddes, Otala, and white papers by Pass?
Or is the thing about these gentlemen that they provide Morricab's confirmation bias for his own preferences?
I love the music of Dmitri Shostakovich
Edits: 09/18/15
"And more all the time with so many class D amps hitting the market? Is it JUST that they are cheaper to build or what? (After all, Lamm is on the pricey in absolute terms, not to mention $$/watt.)"
They (Class D) are extremely efficient, (Up to 90%) ergo cheap watts to manufacture.
Myself I didn't notice many that are impressed with them. I suppose some just like to be a bandleader of the "new" technology.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Personally I'm not using a class D amp but I have owned a couple; they were quite good.
I love the music of Dmitri Shostakovich
Ah but you did and now you have what? Pass, right? Guess the WOW factor wore off and the emperor had no clothes afterall.
The my Pass is a great amp though, I believe, it doesn't even meet all of your criteria of a correctly designed amp. I didn't abandon my class D because per se it was class D but because of the sound of the Pass.
If I had been just slightly more financially constrained, I could have lived reasonably content with my $700 Class D Audio. As it is, there is one respect where I prefer latter: the CDA takes 10-15 minutes to warm up vs. the Pass with take 40-60 minutes.
I love the music of Dmitri Shostakovich
Ah, so you would go back to that amp and give up your pass now...thought not...
You are right the Pass fails on a number of points...mostly because it is push/pull, Class AB and uses negative feedback. The distortion then will not fit an appropriate pattern for maximum invisibility to the listener.
You are not using a Class D amp. because obviously they are still not good enough. Shostakovich sounds best via a good Class AB amplifier , it does for me.
... If I ever have cause to replace my current amp. This amp is a Pass Labs X150.5 which is pretty remarkable and the best amp I've owned, however its new price is $5500 (last I checked). My Class D Audio SDS-258 which is about $700 is 85% of the Pass; it is the second best amp against previous amps of up to 3 grand.
I love the music of Dmitri Shostakovich
Have you even tried a SET before? They too have to be designed correctly (see my original post about output transformers).
... I'm not likely to.
I love the music of Dmitri Shostakovich
So many 'd' amps exist because they are EASY to build. I could become a manufacturer for probably 50k$ or less.
BUY modules and PS from Hypex, B&O, IR, or maybe a few others. Have cases fabricated and hire some reasonable people who can FOLLOW SPECIFICATIONS as to assembly and test.
Minimal Risk and good profit margin. What's not to like? At least from a business model point of view.
Their ARE original 'd' designs, like Spectron and a few others. But they are $$$. Maybe even made in relatively small numbers. Or by companies with poor LONG TERM prospects?
Too much is never enough
There is something called supply and demand at work...If people didn't want them, no one would be building them.
They are in demand because people like them...
try it! you know you want to!
For a second there, I thought you were talking about amplifiers.
:)
Certainly.
But, you'll end up with what's known as a 'ahake out' where the least profitable (NOTE: Not Smallest) manufacturers go out of business. Like a guy who has a real engaging and well thought out case design who thinks he can now be a player. Spends a bundle on inventory but is not necessarily a business guy. Good amp? For sure, just not making enough money and he doesnt' know how to fix it.
And since everyone is using modules from what is certainly a fairly small menu, the NEXT problem is one of 'unique selling position' or 'point'. You start talking about input circuits and modifications of factory modules. In the case of NON-Power Supply equipped modules, the design and construction of the PS becomes a possible selling point.
Companies like Spectron and whoever else makes a Proprietary 'd' amp have an advantage here. And since they ARE proprietary, have complete freedom of design and are not 'stuck' with potential compromises of being a module installer.
So sure, S+D is certainly at work. But so is the rest of econonics.
I'd say the good leverage may be what BelCanto appears to be doing. Working WITH Hypex for a dedicated design / mod schedule for Bel Canto ONLY. Now that's good marketing and I'm confident they'll preserve The rest of BelCanto's design and Sound goals. You also have to be able to BUY enough modules to make this work.
Too much is never enough
those that own the tech will be in the best position, followed by those who can differentiate their product.
But, as I said, the simple reason there are so many out there making class d amps, with more companies, both start ups and long established marque names entering the field, is because people want them...
try it! you know you want to!
And most class D amps. Merrill and Acoustic Imagery come to mind. This is true with ICE and other modules as well. W4S adds a buffer, but still uses the modules mostly intact. D-Sonics had W4S design buffers for them to put in front of their PASCAL and ABLITEC modules.
Bel Canto? Some minor tweaks.
People want them due to being "flavor of the month", and being overhyped.
There's nothing wrong with that, they are for the most part relatively cheap and decent sounding. That said, I'm not going to pay someone $10-$12K to put a module in a box.
Only a small number are doing any sort of rebuilding. Gilmore, Spectron and Auralic come to mind, redoing the power supply (read linear analog) and redesigning the digital output.
Jack
nt
try it! you know you want to!
With the possible exception of Bel Canto, none of those I mentioned are using OEM added circuits, they are using their own proprietary circuits. I don't see that trend. Most of the others rest are just sticking modules in a box.
Jack
adding their own circuitry rather than just popping a module in a box...
try it! you know you want to!
Theta is, for $14K. Merrill isn't really,just tweaks one can do at home. Bel Canto is putting a small circuit in front of the module. Big whoop. That's still mostly just putting a module in a box.
Jack
Are you familiar with the newer Merrill Taranis? Many of those using the newer nc500 are doing more than simple add on mods...
Bel Canto has their own input buffer and has worked with Hypex to make other customizations- I don't know many average consumers who could design and implement their own input buffer. NAD worked with Hypex to tailor and customize the module and power supply for NAD specifically. Levinson did considerably more as well...
try it! you know you want to!
Yes, I know of the Taranis. He's basically using the same PS that's used with the nc1200. His nc1200 amps are still basically just a module. Throw on a pc nd some footers.
Adding an input buffer before the module is still using the module, just like W4S does with the ICE modules, just like d-Sonics. They are still just basically modules. Put it in a box, and declare it "made in US".
Jack
nt
try it! you know you want to!
'Own' what tech? The patents / copyright of modules is owned by the manufactureres. You buy the right to use the modules and might even have other restrictions.
IMO, the BEST companies will be those with prorietary design and mostly In-House build. Those already IN the module install space should be in a good long-term position. Some, like NAD and ROTEL have a more diverse line.
And the reason so many newcomers? They sense Easy Money and High Profit margins with somebody else doing 85% of the heavy lifting.
If the history of HighEnd is anything to go by, MOST of these guys will be gone in a decade or less. And the gear? No matter how well reviewed, will be in the hands of 'fans' and used pieces will be sold back and forth between THEM.
Few manufacturers will reach the level of say, Threshold, or even the original Carver gear.
Kur, you are one of the Big Fans of 'd'. Why aren't YOU making and selling an amp? Tough coming up with a killer 'Unique Selling Position', isn't it? Not to mention startup cash in a very competitive business.
Too much is never enough
that is driving people to enter the market. If no one wanted them, no one would be making easy money wiring up the modules and dropping them in a case.
No doubt those with their own IP are in the driver's seat. The problem many are facing is that designing a first rate class d amp is no walk in the park. There are only a handful of people that have what it takes to do it. As a result, many traditional amp manufacturers lack the technical chops to create their own and thus have no choice but to buy someone else's.
Undoubtedly those that simply package up someone else's module won't be around for the long haul. We are already seeing the move among manufacturers to add their own circuitry to differentiate their product.
I have no desire to enter the class d amp manufacturing business. It's a hobby- if it becomes a job, I would have to find another hobby....
try it! you know you want to!
No BETTER way to ruin a hobby than to turn it into a business.
Too much is never enough
nt
try it! you know you want to!
Some class d amps are cheap and some are expensive. Just like some ss and tube amps. But when a class d amp costs $10K, people whine and complain about how class d is suppose to be cheap and it must be a ripoff, never mind the performance. It's apparently ok though for a tube or ss amp to cost $100,000 and perform no better than the $10K class d.....
Class d is hardly "new". It has been around for at least 30-40 years. It has only been recently though that it has matured to the point were it can compete on an even basis with ss or tubes.
And while you haven't noticed that many were impressed by them, the growing list of manufacturers "switching" to class d products is quite substantial.
try it! you know you want to!
"Some class d amps are cheap and some are expensive. Just like some ss and tube amps. But when a class d amp costs $10K, people whine and complain about how class d is suppose to be cheap and it must be a ripoff, never mind the performance. It's apparently ok though for a tube or ss amp to cost $100,000 and perform no better than the $10K class d....."
-For the record, I start to whine when any audio device starts to grossly exceeds the sum of the parts.
A good 2 channel amp shouldn't cost more then $4000-$5000 tops if one chooses to have premium parts.
I suppose people whine about expensive class D amps because at the core, they are using the same OEM chips as the cheaper ones. All that is left is a few incidental parts and a stout power supply which really isn't all that expensive.
There isn't any antique chips or chips hand made my an old Japanese guy to justify those kind of premiums.
"Class d is hardly "new". It has been around for at least 30-40 years. It has only been recently though that it has matured to the point were it can compete on an even basis with ss or tubes."
-Yes, that is why I put it into quotes, sorry for the confusion.
I suppose it has matured as much as standards have dropped. Also a potential market has been opened up in recent years.
Time will tell whether we actually need Class D for some devices, as battery technologies have pretty much offset the need for it.
"And while you haven't noticed that many were impressed by them, the growing list of manufacturers "switching" to class d products is quite substantial."
-Well sure, can't blame them for trying to make more money. Granted a lot are the same companies that have pushed everything else solid state over the past decades so it is not much of a leap.
Other companies are so obscure it is totally irrelevant to HiFi what they do.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
I suppose it has matured as much as standards have dropped. Also a potential market has been opened up in recent years.
Good one!! Next we'll hear " It sure does make my low bit rate MP3 sound great"
All equipment today with high-end aspirations sells at high mark-up. It is a marketing strategy that allows short-run manufacturing.
It short-run, high mark-up products ensures that virtually all high-end equipment retails for several times the cost of its raw components.
I love the music of Dmitri Shostakovich
More to costs than the parts....Research and development costs need to be added in as well.
Class d audio amps are said to be much more difficult to get right and take a different skill set than those needed for ss and tubes. Few people have those skills, thus why most buy modules.
Some of the module users use cnc cases and other jewelry which adds $$$.
The ncore1200 module from Hypex used by several in their high end amps are said to be sold by Hypex with a minimum price requirement so the reseller's hands are to some extent, tied, in that case.
try it! you know you want to!
"More to costs than the parts....Research and development costs need to be added in as well."
-Sure, but that could be said about other technologies also.
From some aspects, it is easier with class D as it is basically a chip amp, the bulk of engineering and manufacturing is already done.
"Class d audio amps are said to be much more difficult to get right and take a different skill set than those needed for ss and tubes. Few people have those skills, thus why most buy modules."
-Doesn't that set off bells that tell you it is severely compromised design from the start?
If somebody had the skills to make it "right", one wonders why they haven't been implemented by the chip manufacturers by now.
"Some of the module users use cnc cases and other jewelry which adds $$$."
-Form should follow function. If it doesn't sound good in a cake pan...
"The ncore1200 module from Hypex used by several in their high end amps are said to be sold by Hypex with a minimum price requirement so the reseller's hands are to some extent, tied, in that case."
-Even still, I doubt they are paying more then 2 figures per chip.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
I don't follow you....There is more to most class d audio amps than a chip....Look at the Hypex ncore. It's not a chip...And they cost quite a bit more than 2 figures...
try it! you know you want to!
Isn't that the n400 in your signature?
You are right, the correct term would be "module" I suppose.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
both directly due to problems with their methodology or conclusions, and indirectly, as you have with your point that there are legions of "wrong" amps that not only have gotten rave reviews but are commercial successes with many happy owners. Clearly there isn't any universal methodology or inherently superior class or topology. Given the variation in associated equipment that makes up a system, as well as the variation in tastes and preferences, it is ludicrous to suggest otherwise.Of course there are always rationalizations: reviewers are biased, anyone who thinks otherwise is ignorant, deaf, inexperienced, etc. The lengths some will go to defend a position (humans, at least some of them, can hear EVERYTHING, ALL distortion is audible, and other gems of science (fiction)) is simply amazing.
If we were talking about smell, taste, or the other senses, I can't imagine anyone arguing that humans should prefer the same beer, food, color, cologne, or underware, yet when it comes to sound preferences, here we are in crazyville...
I think it would be quite interesting to see the reaction if this discussion where moved to diyaudio.com where Nelson Pass, Bruno Putseys, and many other audio pros who have ACTUALLY designed and put amps to MARKET are regular contributors....
try it! you know you want to!
Edits: 09/18/15 09/18/15
I think it would be quite interesting to see the reaction if this discussion where moved to diyaudio.com where Nelson Pass, Bruno Putseys, and many other audio pros who have ACTUALLY designed and put amps to MARKET are regular contributors.... - Kuribo
This has been flogged to death on DIY with the same results.....
Edits: 09/18/15
I think most of the amp designers there would get a good laugh out of the premise of this thread.
try it! you know you want to!
his SIT amps were specifically designed to meet all of Brad's criteria:
"The SIT-1 is the first of a new generation of power amplifiers using Static Induction Transistors (SIT) in single-stage, single-ended Class A circuits delivering superlative sound without feedback or degeneration."
Here is a Pass quote:"As I said at the beginning, this has been an interesting amplifier to develop,largely because it has contributed to my depth of knowledge as to what techniques make for a good sounding amplifier. Of course this is a subjective thing, and no amplifier is the best for all listeners and situations."
Oh, and he does indeed espouse the use of negative feedback. If you had bothered to read the thread you would know that, LOL....
try it! you know you want to!
Edits: 09/21/15
If you had followed my link, you wouldn't have put your foot in your mouth. Pass is not a liar, despite your weak attempt to make him one.
You are referring to the F6 amplifier where you'll find the quoted text. Hint: that's another link. :)
Because he understands well what I have been saying, in fact, has even said "this is a subjective thing, and no amplifier is the best for all listeners and situations."And he does believe in using negative feedback, again, if you had read the thread I linked on diyaudio.com, you would know that.
His SIT amps are just another flavor, perhaps meant to cater to those who prescribe to the no feedback dogma. He is a businessman, after all, who also happens to have mind open to experimentation and different approaches.
try it! you know you want to!
Edits: 09/21/15
"His SIT amps are just another flavor, perhaps meant to cater to those who prescribe to the no feedback dogma. He is a businessman, after all, who also happens to have mind open to experimentation and different approaches."-No, it isn't another flavor, he is striving for a benchmark that hasn't been met or exceeded by anything SS.
That is why he is experimenting with virtually unobtainable exotic transistors in hopes to achieve some of the traits of the triode.
He posts quite regularly at DIYAudio, perhaps you should ask him yourself."He is a businessman, after all"
-Just like the folks at Hypex, who aren't the first to exploit the ignorant masses with misleading advertising specifications.
This has been going on since the dawn of SS with the power wars. More this, less that...
It got so bad that the federal government had to step in and apply a power testing regiment for 2 channel amps and fined manufacturers who weren't truthful about their power ratings.On a side note, I have a 2000 watt home theater in a box for sale, you interested?
The sad reality Kirby, is that pulse width modulating amplifiers reproducing low frequencies will compromise high frequency reproduction and are extremely sensitive to speaker loads.
I am not aware of any SS amp out there that can reproduce consonants the way the old triode can, all of them ruin the sibilance.
Once you are aware of this, it becomes the elephant in the room, the triode will completely ruin any further SS experience. You will hear the high order distortions on every "S" sound.Maybe somebody has a nice SS amp out there somewhere, but I can guarantee it won't be a Class D amplifier, lol! and it won't be cheap or practical compared to a little SET that need only cost a couple a grand tops.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/21/15
"The sad reality Kirby, is that pulse width modulating amplifiers reproducing low frequencies will compromise high frequency reproduction and are extremely sensitive to speaker loads."
Extremely sensitive to speaker loads? Surely you mean SET's because ncore, a class d amp, had you taken the time to look at the specs, and understood them, is about as load independent an amp as there is.
Your ignorance of this topic continues to astound me. There is no point in discussing this with you further because you lack a basic understanding of the topic. Do me, and yourself, a favor, and educate yourself by reading through the ncore specs and documentation. Then, if you want to discuss it, by all means have at it. Until then, it is pointless and a waste of everyone's time.
try it! you know you want to!
A good SS amp, hilarious.Amps dont work in vacuums, if the pursuit is SOTA level hi-fi , no SET type amp with flea power is going to do it , well, unless you have a horn behemoth spanning 12 ft in width , you can forget about it. SOTA speakers are large for a reason , the amplification to drive them is too, very few SOTA systems will have tooby amps,( unless 12 ft horns) you guys need to get off this, tooby microphonic halo BS and stop reviewing amplifiers in a vacuum.
SS amplfiers can and do deliver, just like toobs , they are not all equal, most of the bad sound most hear is coming from the monkey coffins/ room interface in front of them ..
Regards.
Edits: 09/21/15 09/21/15
A good SS amp, hilarious.
Yeah they are a bit of joke if you want truly good sound...
OK, so no SS , give me a list of your top 5 Toobs ....
No, you give me your top 5 SS amps and why then you might get a list from me. Then your top 5 livable tube amps and I will give you the SS amps I might be able to allow in my home.
Best tooby , there is only one .....
Edits: 09/22/15
Well, those are something alright...but are they push/pull...tsk tsk ;-).
Let's (correctly) attribute his comments, shall we?
These quotes are from Audio Distortion and Feedback
" Negative feedback can reduce the total quantity of distortion, but it adds new components on its own, and tempts the designer to use more cascaded gain stages in search of better numbers, accompanied by greater feedback frequency stability issues.
The resulting complexity creates distortion which is unlike the simple harmonics associated with musical instruments, and we see that these complex waves can gather to create the occasional tsunami of distortion, peaking at values far above those imagined by the distortion specifications. "
nt
try it! you know you want to!
He uses feedback...
Not surprisingly, nuance eludes you in multiple areas.
What he uses is "small" amounts for stability. There is quite a difference between small amounts and heroic (80 db) used by your hero. Let's follow more of his thinking, shall we?
This is from the Xs brochure . (Yes, Virginia that is another link!)
" They found the sound of the [zero feedback] SIT to have truly remarkable properties and it was quickly decided 'Whatever this is, we need a way to bottle it'. Not only did we need to bottle it, but we needed to put it around a much bigger bottle.
In a subjective area where engineering has limitations , it is extremely useful if you can recognize what you want when you hear it. It you have an example of the sound you are looking for, there is great advantage.
Because the sonic quality was so striking , it became easier to discover what modifications to the circuit would make it go away, and by the process of varying the design and listening to the result ...A small amount of feedback was employed around the output stage
nt
try it! you know you want to!
and have done so several times in the past month or so - I'll leave you with his take on switching amps . BTW, the pic is one he built. :)
As with my previous four posts, I'm linking to the source to eliminate confusion (on your part). Let's review his thoughts:
" Class D amplifiers are switches with tons of feedback.
It's amazing they work as well as they do. "
But nice straw man.....we already know he believes in feedback and that amp choice is subjective....
The ncore will be there when you tire of your distortion....
try it! you know you want to!
I don't know about that one Kirby, Putzeys hasn't done anything besides switching amps since he got out of school.Pass on the other hand has a much more diverse and successful background. He is a cult legend for a reason.
Class D isn't black magic, heck, even I could cobble one together, as mentioned before it is nothing new or exotic.
It is challenging, in the sense that it sucks for audio.Back on topic, which believe it or not is not Kirby's class D amp...
Here are some interesting quotes from Pass's wikpedia page:"The SIT chip combines a square-law input character with a low impedance output to form the only solid-state gain device, which Pass claims, "behaves like a triode tube.""
"The point of the SIT is that it behaves like a triode but at lower voltages and higher currents, so it doesn't need a matching transformer to deliver power to 8 Ohms. "
"SITs have a curve which looks a lot like a triode vacuum tube; low at first and climbs steadily. The distortion curve is similar, a steady rise instead of a valley with high distortion at both ends." (Which is what Morricab stated when he said SS made more distortion at low volumes.)
So, I would consider Pass's SIT amps as "SOTA", not to be confused however with the "pinnacle" which was developed by De Forest over 100 years ago.
Everything since then, has been a compromise in one way or another.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/22/15
Putseys started designing and building tube amps. He has moved on with spectacular success.
Pass' products are all ss as far as I know. He once tried a class d amp but couldn't get it to perform well.
And yes, building a class d amp is not hard. Building a good one is. Just ask those who have tried.
try it! you know you want to!
Well maybe you know more about Putseys then is public record?"Early life
He graduated cum laude at the National Technical School for Radio and Film on the subject of power stages for switching audio amplifiers. Worked for 10 years at the Philips Applied Technologies Lab in Leuven, Belgium, where he developed various digitally and analogue controlled class D amplifiers, noise shapers and modulation methods, and invented among others the "UcD" class D circuit."
"Career
In 2005 he left Philips to divide his time between Grimm Audio and Hypex. Current activities include designing high-performance discrete AD/DA converters and analogue signal processing circuits, DSP algorithms, class D power amplifiers and switch-mode power supplies. He holds several patents in the fields of digital audio and power conversion and has published extensively in these and related domains."
It doesn't say anything about tube amps...
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Edits: 09/22/15
Here's one
He dabbled briefly as a teenager.
Well, you got me.
I guess Putzey has the same pedigree as hundreds of others over at DIYAudio after-all.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
the section about his music collection:
"Along another wall in the living room are shelves with an eclectic mix of a couple of hundred CDs..."
Makes perfect sense that analog and high resolution are absent.
How many CD's in your collection ..... ?
along with another 600 vinyl and several dozen high rez albums.
I have heard the Grimm active speaker system now several times here in Switzerland and each time it is totally clear and precise and STERILE and UNmusical like hell. I can't stand more than a few minutes in the room with such an utterly unmusical "mr. Spock" like sound. Grimm indeed...
.
There are as many conceptually wrong transistor amps as there are tube amps conceptually wrong, and right. The Rowland and other companies are refining Class D circuitry to be very good amplifiers. Tube circuits or pure Class A circuits do not ensure musical reproduction. I have heard very musical systems with very diverse amplification. The key is the careful matching of amplifier and speaker. My preference is speakers that work well with tubes. Jallen
Agreed. The room is the final frontier as many of us do not have dedicated listening rooms, and have to mix the audio placement with WA interests. Jallen
nt
try it! you know you want to!
Who wants the perfect amplifier, or perfect anything? Once perfection is achieved, what do you have to look forward to?
Silly person.
This sounds right on.
It will likely ruffle a few feathers, it will be another thread that quickly reaches 100 post then starts to shrink. lol
Cheers
△ᴉʇɐuᴉɯnllI oᴉpn∀△
Well, you know...just keepin' it real :)
Much of what you've "discovered" is news to whom?
Still, thanks for the thoughtful and informative post. It never hurts to be reminded of things and to learn a new thing or two.
While we're talking about harmonic distortion, let's remember that it is "natural" harmonics, not "equal temperament" harmonics. So, once you get past the first three or four, things start to get ugly, sound-wise.
:)
Not sure what you mean by "equal temperament".
This:
Harry F. Olson, "Music, Physics and Engineering", second edition, page 48.
Edit: Not to be confused with the scales of "Just Intonation".
:)
Edits: 09/19/15
This is why our amps are built the way they are. You are incorrect about Push-pull, although there is a gradient there and most of the time your comments are spot on. We got around a lot of the problems you mentioned by getting rid of the output transformer and the dedicated phase splitter circuit.
The result is an amplifier that conforms quite closely to the parameters you set out.
Why don't you make a zero feedback SE(OTL) and we can see how it compares on a suitable speaker. Those other OTL guys have made one (but not without feedback). It doesn't have to have a lot of power just has to be done right. Might need quite a few tubes in parallel to get the output impedance down without feedback but...what the hell... your MA-2 uses a LOT of tubes too.
-There seems to be less incentive to go single-ended.
OTLs of course have their own issues often opposite of that of SETs. Instead of the bigger SET with full bandwidth being a sort of holy grail, with OTLs the low powered amp is the holy grail. Of course, the smaller you make them the less efficient they get, although 5W OTLs are possible.
But if you build one that is single-ended, they get even more inefficient!
Unlike solid state amps though, where the 3rd harmonic gets squared by the power, in our amps the 3rd harmonic is a bit better behaved, so even at full power with zero feedback the THD can be at or below 0.5%.
RalphIMHO the Real GNFB-free SET-OTL have to be configured that power triode(s) OPS have to be connected conventionally as Anode followers but not as Cathode followers to get that recognizable genuine SET sound ,
but in the same time to make&get acceptable power amp efficiency ( Pin/Pout )from SET-OTL only way to go is to design custom HQ-LS with very high static Z .
__
"Art which does not have the appearance of art is true art."
- Old Roman saying -
Edits: 09/26/15
I would say there are two schools of thought (at least) for what makes the best SET. There is the big transmitter group and then there is the small triode group (who like the 300B, 2A3 and the 45), which are arguably more linear than the bigger and the indirect heated group...but severely limited in power.
I have gone somewhere inbetween with a parallel 300B and parallel 6C33C amps. I would, however, like to get hold of a good 211 based amp.
Now SEOTL, sure it would be terribly inefficient but 10 good watts with the right speaker might be the best option.
Morri,Just buy an FMA, you are near to manny , he will let you audition one at home and stop all this 1,2,4,5,10 watt nonsense ..
Regards..
Edits: 09/25/15
FMA?? Sorry, don't follow you.
BTW, I went to hear the Devialet 200 on a pair of Wilson Sasha W/P2s today. The speakers are 40K and the amp 7k. How was the sound?? Tight, clean and smooth but quite dry overall with overly damped sound decay and over damped bass. Not a terribly musical sound but listenable. I would bet that any good hybrid, PP triode amp or SET will make a much more interesting listen.
We also tried the Devialet 120 on a pair of the new Wilson Sabrinas. It was significantly less dynamic sounding than the Sasha and overall less interesting. I was disappointed with the overall sound for 20K speakers.
In the end it didn't change my opinion on the Class D sound. Sure they are more refined than many other Class D I have heard, I guess that is the influence of the small Class A amp helping out...however, it doesn't get there finally.
I would think the issue was more the WA speaker , than the Devialet's, again with Devialet the bigger the better , try the 400/400 and hear the difference. Albeit there is some lack of involvement with some Class-D, i did not experience that with the Devialet's , but the listening session was only for an 1 HR ...
FMA, I thought all Swiss knew this and Manny Huber ... :)Regards
PS, Dartzeel 108
Power output with 1kHz test signal
8-ohm load at 1% THD: 142W
4-ohm load at 1% THD: 158W
RUN .. !!!!
Edits: 09/26/15
1kHz signal at 10W into an 8-ohm load
Dartzeel NHB 108, I know Uncle Mikes and others like their sound alot , must be the same way others like high distortion SET toobs..
Edits: 09/26/15 09/26/15
What can I say? It didn't impress me at all and I heard it at the designers own house...but then I don't have Musical Fidelity "Titans" as my reference...
Have you tried FMA..? I think the Dartzeel would work well on your horns , high z-mag and sensitivity fits this amp distortion vs power profile ...
Again, what is FMA? I disagree with your assessment of the dartzeel data. It doesn't drop significantly with power so at the powers I am likely to use it will be signficantly more distorted than my tube amps and with lots of harmonics that are also not ideal for natural sound reproduction.
I disagree with your disagree, you still have to try and see if you like the Dartzeel distortion triats as much as your tooby distortion traits. I know it wont work for me , the Ribbon panels are 1.5 ohm and the bass towers are 3 ohms.
As to FMA, I'm shocked you are not aware of them or Manny Huber, its the best SS amplfiers in dah whole wide world , the only one better than toobs and in your backyard to boot.FMA:
Load Impedance:
No minimum impedance. The amplifier is designed for 1 Ohm to 10'000 Ohm systems. It can drive any speaker impedance (even below 1 Ohm) with dynamic (music) signals without any limiting, compression or other negative effects on the audio signal. Despite this, the amplifier is fully protected against short circuits, open circuits and all other adverse conditions via a unique onboard computer that continuously surveys all important parameters.
Regards.
PS : I have a knew tooby , an SET , going to use it in my studio, those mid field monitors are 91db/8 ohm small room , hope it gets close to the Cary's, sadly only 5 watts , listening distance is only 1M thou so , chip chip..
Edits: 09/29/15 09/29/15
And you seem not to be able to read anymore...I have heard it more than once and found it wanting...so I have "Heard" its distortions.
What kind of SET did you get? With only 5 watts it must be something small but at 1 meter it and 91db/watt meter it might be ok.
maybe if I need an arc welder someday I could consider this FMA...
I had the Cary CAD-572se monos a few years ago...they were pretty nice sounding...not too warm but natural. Measurements in stereophile from Martin Colloms look pretty promising...always wonder how they would sound if you removed the 2db of negative feedback that Cary applied...they could even make a pretty honest 20 watts. Now some friends have them and they love them with their AudioPlan Kontrast IIIsi speakers.
darTZeel's NHB-108 fills your bill except that its output stage is a complementary pair of solid-state devices.
The same can be said for the 50Wpc stereo amps made long ago by Krell and Plinius, which are still legendary for their listenability.
So, I think you are onto something, but that perhaps your criteria can be loosened up just a teeny bit.
ATB,
jm
Umm, no it doesn't...see comments below.
Great post!
Thanks for boiling your notions and study down to a digestible batch. I follow your posts and while I don't see eye to eye with you on some of the root cause and implementation issues, I definitly think that you have the right sort of concerns.
Knowing what our magic ears will regard as 'natural' and pleasing is the royal battle.
Rick
Just for the sake of discussion where do you disagree? Don't worry, I have been posting here a long time...I have a thick skin ;-)
"Just for the sake of discussion where do you disagree?"
Well, naturally no distortion is the ideal all right... the goesouta should look like the goesinta, just bigger and with a consistent delay. In other words, a linear, time-invariant system. The delivery time for perfect systems does tend to be annoyingly long however so we often accept at least SOME compromises...
I admire what you are trying to do but it's probably bootless: way to many variables to really be able to nail down universally applicable design rules. Minor implementation details will blow the boat out of the water. And then, there's the tastes and sensitivities of the user...
Best, Rick
Well, naturally no distortion is the ideal all right... the goesouta should look like the goesinta, just bigger and with a consistent delay. In other words, a linear, time-invariant system. The delivery time for perfect systems does tend to be annoyingly long however so we often accept at least SOME compromises...
I don't disagree but since there is no such animal I think my "rules" will get you something pretty good.
Then start comparing the TF and if so how important is the Squarewave responses ....
No Class B or AB: Crossover distortion is an issue and must use negative feedback otherwise distortion would generally be unacceptably high and highly audible.
Tell that to Ayre
If I ever meet CHarles in person I surely will...he might even agree with me but you know he's gotta sell amps and it is easier to the brainwashed I suppose.
Based on what I have heard from Ayre they aren't bad...his Theta Dreadnaught design was quite good on some Thiels...but a pair of BAT VK120 monos were a lot better...
The only point I was really making is that Ayre has been making low distortion Class A/B SS amps with no feedback anywhere, so it certainly can be done.
I don't know which amp is better but the statement means nothing until you define better in a way that many knowledgeable people basically can agree on.
Have you injected a pure sine wave into all the amplifiers you are complaining about and put a frequency analyzer at the output to see these harmonics?
Norman Crowhurst would be a good place to start. You can download the most relevant texts at the link below.
Scroll down to 'Basic Audio' pub. 1959 by Norman Crowhurst. It would be a good idea to read all three.
I seriously recommend you start backing up these absurd claims with real lab data and stop using out of date references to try and come up with a weak counter arguement.
Norman Crowhurst is impeccable in his work and it has stood the test of decades. I even posted a link for you to make it easy.
If you don't know who he is that in itself is really telling. Read up.
Can you proved a link or two?
I love the music of Dmitri Shostakovich
If you don't know who he is your background in audio is incomplete. He is one of the better technical writers to have documented amplifier design in the 1950s.
OTL's are load intolerant , actually all amps to some degree are, so discussing them in a vacuum is partially irrelevant as none will achieve greatness if not matched to the correct driven load.Best 8 ohm amp design
Best 4 ohm amp design
Best 2 ohm amp design
and so it goes ....
Regards
Edits: 09/18/15
In the case of all amplifiers, tube or transistor, the 4 ohm distortion spec will always be higher than that of the 8 or 16 ohm spec.
IOW, if you are really serious about getting the best out of your amplifier dollar, it will be best served by a speaker that is 8 ohms or more. Four ohms helps you get more power if your amp can double power into 4 ohms but that is not an argument for quality, its an argument for quantity and a poor one (3db) at best.
Of course, many people say something like ' I have four ohm speakers and they sound great', and they probably do, but if you could change them to 8 ohms without changing anything else, they would sound even better. Its not a good idea to make any amplifier work hard; the result will be harsher sound with less detail due to increased distortion.
FWIW, our M-60 amplifier makes 60 watts into 8 ohms. It does not do so well into 4 (although we have 3 larger amps that do) but if you just make sure that the speaker is 8 ohms in the bass the amp can do quite well. IOW its not really that hard to find speakers that work with it; its our most popular amp and we are still here after 39 years...
So now the Distortion spec counts for sound quality ..:)
The best systems i have ever heard , had multiple big amps and large multi driver speakers , of course nothing that could be driven with an OTL nor an SET amplifier and they were'nt anywhere near 16 ohms. Power is very much necessary for realism, regardless of sensitivity, do the math and the scale is the same low- high. Speaker size is also very necessary for realism, The percussive energy required to sound real (to replicate real instruments ) doesn't come from little speakers running on small amps.
So , yes distortion increases with low -Z, but how much is too much and only because the class-A bias and feedback used is diminished as you lower drive impedance , PSU noise not withstanding.
IMO,
It's Very important when pursuing SOTA dsigns to have a load tolerant Amplfier, Since the typical dynamic speaker is not a resistor and will have low-Z values below it's nominal, Which Brings us to your original Picked bone.
There is no such thing as a 16 ohm speaker sounding better, just because it happens to represent a Nominal impedance of 16 ohm, a multiple of said speaker operating at 4 ohm, will sound better if not amplfier limited, as the lower thd and increased sensitivity achieved by doubling Driver surface area, will overcome the ususal slight increase in THD from the amplfier, unless inadequate (Halcro) or not designed to do so (OTL).
Regards.
My speakers at home are not only 16 ohms, they are also 98 db 1 watt/1 meter.
I agree completely that the amplifier power is necessary for realism- I can get to 110-112 db in my room at the listening chair without clipping the amps. They make 140 watts into 8 ohms...
The speakers go to 20Hz and have no breakups in the audio passband thanks to careful crossover work and beryllium diaphragms in the midrange unit, which does the lion's share of the work.
I've yet to go to a show or a customer's house and hear a more convincing system, although as we both know that's no definitive measure. Regarding the distortion issue: when you run the distortion up on any amplifier by decreasing the load impedance, the distortion component will be of the most audible type (IOW higher orders), so yes to "So now the Distortion spec counts for sound quality ..:)", as the higher orders are readily audible even in trace amounts as brightness and harshness.
Regarding the 'no such thing' comment, actually there is a way to demonstrate that via the use a transformer to convert the load impedance. The fact that you went from 4 to 16 ohms is readily audible as a smoother sound with greater detail, this on a solid state amp that has no troubles doubling its power as the load is halved. The autoformer used for that test BTW has bandwidth to nearly 2MHz due to the turns ratio being so low. So it does not appear that the autoformer itself is the variable. In interviewing a number of manufacturers at shows, a common comment regarding this topic was (paraphrasing) 'yes, just because an amplifier can double its power is not the same as saying its sounding it best and in all likelihood it isn't'.
'cause that all sounds like more subjective opinion, not fact.
try it! you know you want to!
I've yet to see anyone that was objective- they all express subjective opinion sooner or later...
But actually its been well-known since the 1930s that the 7th harmonic even in trace amounts (0.01% for example) is quite audible and contributes to brightness and harshness. If this is news to you then you need to read up.
Our good friend John Curl has been trying to pound that into my thick skull. :) He's been a student of the study of distortion types, their audibility, causes and solutions for darn near his entire career, as far as I know.There isn't anything "magic" about the 7th harmonic, it's just that that's approximately where it starts to become noticeably dissonant and irritating. There are good reasons for this, as we all know.
:)
Edits: 09/24/15 09/24/15
and that is why it was detected as a harshness 'way back in the 1930s...
John Curl is spot on BTW...
Yes but the odd (and even) harmonics above 7th are all dissonant and increasingly so. To be avoided (at least at low power) if at all possible. You become more tolerant of increasing distortion and higher harmonics as the SPL goes up...this is why Cheever's metric is SPL dependent.
Well the class-D im playing with now is very tolerant at low levels , suprisingly so , makes you want to go up in levels and then headache reach for the volume at higher levels .
So no silver bullet yet .....
Is it an ncore? Or something "worse"?
I polled my friend now on his opinion from our Wilson/Devialet adventure and he too was underwhelmed. He said it was all head and no heart...it just didn't pull you in and make you want to listen in particular...a 50K background-while-you-work system...not hold your attention at all.
All WA speakers does that to me , exception in the past , was Watt/puppy on spectral Gear. Most recently i have heard them on Dan D'Agostino's new amp and VTL, both very under whelming, not my sound.
Edits: 09/30/15
The original X1-Grand SLAMM with KR Audio was pretty awesome...I repeated this awesomeness with an X1-MK3 in a shop in Switzerland.
The WP7 sounded quite good with Lamm ML1.1 monos as well and not bad with a big VTL rig...all other demos I have heard were far from great.
I must amend my earlier post in this sub-thread, regarding the 7th harmonic. While in the midst of creating a table which would show why natural harmonics don't line up with equal temperament tuning, somebody wisely sent me a table which had already been created (Thank you!). In fact, although many harmonics are dissonant with equal temperament, the 7th really sticks out like a sore thumb, so, there IS something magic about it.
You can view the table here: http://www.phy.mtu.edu/~suits/badnote.html
But be careful - you could end up spending the next hour or two reading all of the linked pages!
:)
Thanks for the info! I will look into your link.
Very few amplifiers today have the PSU to do the low-Z dance, so I'm not surprised by your comment.
Our MA-1 power supply can produce about 50Amps using the same measure that many solid state amplifier manufacturers use.
The issue here is finesse. If you want to create realism, the last thing you want to do is burden the amp in such a way that it makes more distortion because when it does so, its the kind that is audible.
I think you said it yourself- you have enough power so that there is plenty of power for realism. But you might consider what it is that causes realism in the first place. One thing certainly is a lack of distortion (and by this I am making it clear that I don't like presentations that exhibit a large amount of the 2nd order; while they certainly sound sweet, its hard to regard such as neutral).
But in addition to that power, the distortion components that the ear finds as the most audible (IM, and the higher ordered harmonics) will have to be kept to a minimum. That's hard to do when you have a lower impedance. In a solid state amplifier, the output devices have a non-linear capacitive aspect built into the junctions. This capacitance is magnified by current (BTW, the FM radio in your car is tuned by a device called a varactor diode that takes advantage of this principle). If you want to avoid the non-linear capacitive effects on the circuit, its to your advantage to keep the load impedance higher.
Now you can see this sensitivity to load in the specs of any amplifier, even class D.
Another reason 4 ohms is a hard way to go is the speaker cables. Now I am old enough to remember how I was able to go to Ace hardware and get zip cable, and it worked. But back in those days a lot of speakers were higher impedance. If you have a 4 ohm load the cable is just going to be a lot more critical plain and simple. As such it will induce a coloration, so you inherently have to keep it short. This again is easy to demonstrate. RCA published a nomograph showing just how important the speaker cables were back in the 1960s. Essentially, the lower the speaker load impedance, the more the cable works to reduce the damping factor. At 16 ohms its almost a non-issue.
try it! you know you want to!
-
"But in addition to that power, the distortion components that the ear finds as the most audible (IM, and the higher ordered harmonics) will have to be kept to a minimum. That's hard to do when you have a lower impedance. In a solid state amplifier, the output devices have a non-linear capacitive aspect built into the junctions. This capacitance is magnified by current (BTW, the FM radio in your car is tuned by a device called a varactor diode that takes advantage of this principle). If you want to avoid the non-linear capacitive effects on the circuit, its to your advantage to keep the load impedance higher.
Now you can see this sensitivity to load in the specs of any amplifier, even class D."
So I showed you an example of a class d amp that is not sensitive to load.
Similarly, the IM it produces is below audibility.
Some call this "sterile". I call it accurate.
try it! you know you want to!
The sensitivity to load is just as you quoted me above- the lower the load impedance, the higher the distortion, even in class D amps.
Maybe you should check the specs of the ncore because in some regions, lower impedance loads actually produce less distortion....
try it! you know you want to!
Holy smokes I was just joking about you having 85db speakers, as it turns out they are ~83 db? Wow, I didn't know they made them that inefficient.
Looks like you are stuck with the pucks for the time being, no soup for you!
It says you have a 6-pack of pucks? Is that for surround or are you multi-amping those gluttons?
△ᴉʇɐuᴉɯnllI oᴉpn∀△
RalphI think that most of SS/BJT based amplifiers benefits from 16-ohm load(speaker) vs 4-ohm LS primary from reduced beta drop effect ,
MOS-FET-s ,laterals ,verticals and other FET types don`t suffer from this negative effect , but from high input capacitance which is again highly non linear , and this can be `cured` only with higher standing bias current( A class ) .
Further general problem of SS devices is that N and P complementary power devices is not so complementary as is advertised ,
for example power MOS-FET N & P input capacitances , it is so different , same effect is valid for BJT N & P power devices ,
transfer characteristic is different and not so complementary,
to avoid this N vs P type basic differences some SS amps designers use only same type of power devices , usually only N type connected in SEPP power bridge configuration ,and rarely connected in Circlotron PP power bridge ,
for example somewhere above mentioned Einstein hybrid power amp use Circlotron PP (a)/B class configuration ,
except of this couple examples exist so many others real basic problems related to implementation of SS devices for good audio power amps .
__
"Art which does not have the appearance of art is true art."
- Old Roman saying -
Edits: 09/18/15
In a solid state amplifier, the output devices have a non-linear capacitive aspect built into the junctions. This capacitance is magnified by current
- Ralph
You talking BJT and or MOSFETS, High bias Mosfets dont have this issue , just crank the bias up to reduce. Seriously Ralph, junction capacitance is easily controlled. Tube amplifiers also suffer from parasitic capacitance like anything else.As to speaker wires, we have progressed beyond zip cable at Lafayette, RLC circuits (speaker wires) are available to care of any situation, speakers wires should be short anyway, .5M is about the best , 1M is the max regardless if 8/4/2 ohms , not to mention most good SS amps have pretty low output impedances ....
Regards
Edits: 09/18/15 09/18/15
I guess I'm not understanding why you would want more coloration out of the amp (and distortion of any kind is interpreted by the ear as a coloration....).
you should have seen the PSU on my NAT...20Kg power transformer, 100K uF capacitance, 4 chokes...it is a pretty manly PSU for a 100 watt amp (ok, its class A).
THere is more to sound quality than scale you know...
I would love to see the spread sheet results , I guess measurements do matter .... :)I'm also not surprised "you " came up with an SET as the one , another could prove a class-a fully balanced load tolerant SS amp to be the winner , such is life ..
The Ultimate amp ...? Output transformers would be a no no , Driven load and application sets the animal , which means amp and speakers used would be married as a package, no way to drive towers of babylon with an SET , so no one rule fits all , admittedly, we can agree most design metrics suggested will work when designing an SOTA amplifier , be it toobs or sand , but , its not all or nothing ...
Could you link the measurement of an SET amp with a flat distortion curve ..?
Regards
Edits: 09/18/15
"another could prove a class-a fully balanced load tolerant SS amp to be the winner , such is life ..
Unlikely given the kind of distortion pattern it is like to generate.
"Output transformers would be a no no , Driven load and application sets the animal"
Why would output transformers be a no no? Speakers that are pigs to drive are usually terrible with low level resolution anyway...I know only some electrostats and a ribbon or two that are exceptions but for box speakers...forget it.
"we can agree most design metrics suggested will work when designing an SOTA amplifier , be it toobs or sand , but , its not all or nothing ..."
Well, I did mention that SEP or SE(trans) might work to some extent but as the devices are not as linear (maybe Nelson's SIT amp?) as triodes you are back in the harmonic hot water again. SE OTL if you really don't need much power could also be possible, IF you don't need a ton of negative feedback for it to work.
"Could you link the measurement of an SET amp with a flat distortion curve ..?""
You mean distortion vs. frequency I presume?
Here you go:
http://www.soundstage.com/revequip/lamm_actual.htm
http://www.stereophile.com/content/lamm-ml21-monoblock-power-amplifier-measurements#bSyfUPLf64sMRp5q.97
The Lamm ML2 and 2.1 have quite flat curves...the ML2.1 actually has lower distortion at the highest frequencies.
Morri, yes it's flat to 20K at 2.83V and exhibits some tilt up in the Bass, But you will have to admit the Lamm is special and not at all indicative of what others are using and this is only if you are using it below 2.83V ..
The lamm is not "special" it is just done right.
Except for the one you took off your list ... :)
Well, its push/pull, remember?
A couple tenths of a percent doesn't really count now does it?
Look at the 2 watt IMD spectrum for the ML2.1...not bad at all...compare it to a darTZeel and LOL!!
Having heard both at length (i heard the darT in the manufacturers own home and listening room with their fancy preamp...I didn't get the review...guess I couldn't hide my disappointment in the sound well enough) and the Lamm with both on a compatible speaker will trounce the darT sonically.
You are wrong about something else...you can push it and the distortion character isn't going to change...just increase. But as loudness increases the sensitivity to the distortion also decreases...
NO way to comment on that until i can see thd vs freq at more than 2.83V...
http://www.soundstage.com/revequip/lamm_actual.htm
first figure shows 18, 10, 5, 1 and 0.1 W into 8 ohms...not much change.
figure 2 shows same THD vs. power regardless of frequency as well
Now you can comment...
I agree no one package fits all.
However speakers should be chosen by the limitations of high fidelity amplifier design.
Plenty of speakers will cause hearing damage with just a few watts.
Choosing power hungry speakers first is getting the cart before the horse, it's an uphill climb in which you will likely never reach the top.
P.S. Can you share any links of these unicorn SS amps you keep referring to? I would love to tell you what's wrong with them.
△ᴉʇɐuᴉɯnllI oᴉpn∀△
However speakers should be chosen by the limitations of high fidelity amplifier design.
To each his own, but in my experience, finding a pair of speakers I can live with long term is way harder than finding an amp I can live with. And limiting the search to high efficiency speakers adds another level of difficulty.
I have driven 84db/watt electrostats with 30 watt SETs no problem (do the math you will see it can still get quite loud) and ribbons too. A speaker with about 90db/watt and a benign load will sound better than you thought possible with a good SET.
I have heard what we thought were ho hum speakers turn magical with a top notch SET and I have heard great speakers sound like S#)t with a mediocre amp. Pick the speaker to match the amp and it is a more sure fired recipe for success. Unless your room is huge or you listening habits live rock concert, you don't need monster amps.
We recently did demos at friend who has Thiel CS3.7, which is sensitive at 91db but also has a tough load. Even still, my 35 watt PSE monos drove them better than the guys 120 watt Octave monos, which drove them better than his previous amps, the McIntosh MC501 monos. Truth was the needle was rarely climbing much above 5 watts when he had em and he listened pretty loud...
I admit I have not tried SETs on any of my favorite speakers. I have heard a few different KT88-based amps with my present and former speakers, with mixed results.
The closest I've come to finding semi-high efficiency speakers which not only sound good on a range of different music types but also would work well in my room is the Stenheim Alumine. I auditioned these with VAC amplification and it was superb, although I only listened for a handful of songs because it seemed out of my price range at the time. I regret not giving it a longer trial.
I've never heard Thiel with any tubes, but with mainstream SS they sound tippy. I imagine they would be pretty good with a 30W SET.
"mainstream SS they sound tippy"
No wonder they have extended treble that let's you know what is going wrong up there.
The Thiel speakers I've heard are not neutrally balanced. They suffer from a rising treble response on axis and a recessed midrange. Even if you set them up with no toe-in they are still brighter than what is subjectively, or even objectively neutral.
http://www.stereophile.com/content/thiel-cs36-loudspeaker-measurements-part-2#XpFgijkujbgGdUdV.97
THe CS3.6 (arguably the best Thiel speaker) doesn't have a rising treble (the spike is above 20Khz).
http://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements#MZWA5QC1pSJpIZVH.97
The CS3.7 rises about 2-3db on axis but the in-room response is smooth.
"The Thiels' spatially averaged response in his room (fig.8) gently rolls off above 7kHz, due to the increasing absorption of the furnishings in this region, but is superbly smooth and even between 200Hz and 7kHz"
http://www.stereophile.com/content/thiel-cs5-loudspeaker-measurements-0#oLeZemolXw65LeVX.97
Pretty flat overall considering how many drivers and 1st order xovers.
http://www.stereophile.com/content/thiel-cs72-loudspeaker-measurements#062UrujpFzlapz0d.97
Bit of a saddle shape on this one will give a somewhat distant perspective due to a bit of a depression in the "presence" region. This one is perhaps close to what you describe
My friend's CS3.7s don't sound tipped up or recessed in the mids.
"Even if you set them up with no toe-in they are still brighter than what is subjectively, or even objectively neutral.
"
Again, which amps did you use? They exaccerbate issues with the HF distortion and noise because they are less rolled off than a lot of soft dome tweeter speakers. Nowhere for such an amp to hide like with a lot of speakers.
I haven't heard any of the other Thiel models, but these were among the brighter sounding speakers I've heard. I know the driver integration is sensitive to listening height though and I can't remember whether the setups were ideal in that respect.
Regarding the 3.7 measured in Wes Phillips' room, his later review of the Vivid G1 has an in-room measurement of the G1 compared to the CS 3.7. The response of the G1 shows what many listeners consider a "natural" balance, which falls with frequency about 10dB from 20-20k, roughly along a straight line on a log-log plot. The Thiel's in-room response was flat to 5 KHz, which should sound subjectively bright.
Subjectively bright on the wrong amplifier, as the G1 on the wrong amplfier will sound dull ..
Like I said, I imagine Thiels would do well with medium power SETs. Conversely, I think I would prefer the Vivid speakers with those Soulution amps.
"Like I said, I imagine Thiels would do well with medium power SETs. Conversely, I think I would prefer the Vivid speakers with those Soulution amps.
"
You can imagine whatever you want. ;)
But, as I've been saying over and over, "IT'S A SYSTEM".
:)
It doesn't matter if "this or that" speaker sounds like this-or-that, within the context of the thread topic.
Edits: 09/22/15
Built it .......
Some Class -D have extended treble, you might want to knock your tweeter down a notch when auditioning, They are also very sensitive to power cords and speaker wire (RLC), never encountered anything before this sensitive to such.
Edits: 09/21/15
I think you mean distorted and noisy treble. Both of my SETS have flat frequency response beyond 20Khz...which is definitely extended enough, as did my NAT and KR amps before. None of them required a tweeter "knockdown" although they all extended well beyond the limit of hearing for all humans.
Yeah , Noisy , does respond to wires and cable thou, what list of tooby amps ..?
John Marks pick is a good start .......
WHich is?? Is it posted somewhere or in Stereophile? I don't have a subscription...
The darTZeel??? Surely you are joking...
Stereophile: http://www.stereophile.com/content/dartzeel-nhb-108-model-one-power-amplifier-measurements#uBJ9SibqxZT4kuOl.97
Let's have a look at those measurements shall we?
It has the same distortion at low power as at high power...usually not a great sign
It does have flat distortion vs. frequency...a good sign
However, the distortion at 50 hz shows a picket fence of harmonics...not promising
Soundstage:
"http://www.soundstagenetwork.com/measurements/dartzeel_nhb108_model_one/"
Good THD vs. frequency and evenness of damping factor
But look at CHart 5 at the harmonic distortion at 10 watts at 1Khz...Yikes!!!
Definitely not monotonic and almost certainly audible..
What we don't get from either review though is the IMD harmonics but I think we can guess they are not so good.
Have you heard the Dartzeel's ? from the bench it has too small a PSU for me to give it the full NOD, but it is highly rated and accepted for it's sonics and exhibits good tendency' if used above 4 ohms. speaking of , I'm sure you did not miss the squarewave of the LAMM at 10K , plenty slewing, not as good as the dartzeel, will make bright speakers sound darling.
Yeah , not as straight forward as the charts would suggest..
Regards
Edits: 09/18/15
As stated above, I heard them in the designer's home system. I also saw them being assembled in their workshop and heard them and the big daddy one at a few shows besides.
I won't agree with JM on this or many of his picks for that matter (his recent endorsement of the Wilson Benesch speakers, for example).
Thank you I am checking it out now, it does look pretty nice.
One issue I see right away is that it is $18,000 which kinda raised my eyebrows.
Seems like an awful lot to spend just to almost sound like tubes?
△ᴉʇɐuᴉɯnllI oᴉpn∀△
These toobs with flat distortion curves , would love to see ....
Seen ....
You make a good point- amps are part of a system and as such, not all amps are going to be optimum in all systems. Oh, but wait, didn't you know speaker, preamp, and all other component manufacturers have it "all wrong" too? There is only one best of every component! Silly you!
try it! you know you want to!
Love the out of date references made back in the 50s by Ralph and Tre when transistor development and doping were just in their infancy. These transistors were crude and dirty compared to devices made in the 70s and 80s and even ditier still compared to deices made today. Their tolerances back in the 50s were all over the map and when combined into an amp just compounded the problem despite deploying -ve feedback to reduce the effects of gross component tolerances. Its a wonder the amps sounded as good as they did.
You don't get it...it has nothing to do with the age of the devices...the transistors have the same transfer functions they did then and they are still used in similar circuits...only Pass and a few others are pushing away and finding better sound in simpler circuits using transistors...
Read the article from 2008 from Nelson Pass on his website...it says nothing about "antique" transistors...he is showing the problem with MODERN devices. It is how they are being used that is problematic...and their inherent non-linearity.
Have you heard Nelson's Simpler circuits ?
nope but I would like to
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