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In Reply to: RE: What an astonishingly insightful (and iconoclastic) assessment of some formerly revered designs.... posted by Tre' on March 21, 2017 at 21:05:07
It isn't the device. Triodes can be very linear. It's the topology of single ended and no device can fix that. I've confirmed that with some very good designers including some that produce single ended amps but make them because they like the sound. They are non-linear even with super linear devices.
Follow Ups:
"It isn't the device. Triodes can be very linear. It's the topology of single ended and no device can fix that."
Can you give a technical explanation for that claim?
If the tube was perfectly linear (and none are) then there would be no mechanism for producing harmonic distortion, whatever topology.
With push pull the even order harmonic distortions are canceled but not the even ordered harmonic distortions.
Push pull brings it's own set of challenges.
Either way, HD is caused by the non-linearity of the device.
I believe that you have been misinformed.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I do have to point out that air is a nonlinear medium for the transmission of sound waves. Take a look at the adiabatic pressure/volume curves. The same thing happens, compression of one half of the cycle and elongation of the other half resulting in second harmonic distortion.
"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln
I know and Nelson Pass mentions this. So you're compensating for the air, a tone control for the air? But the topology of single ended still adds one more type of non-linearity to the non symmetry of the air.
I will ad that since no amp is totally linear we end up picking the one we like, hopefully from among the better, more linear amps. It's just that this non-symmetry bothers me when I think about it. And I think it needs to be pointed out that this is meaningful especially given the normal bias of those who like SET citing its simplicity and that it doesn't split the signal and put it back again. SET is more of a trade off than its lovers claim
As for me my bias is for a push/pull triode amp with no overall negative feedback. Plus it allows reasonable power output for todays lowish efficiency speakers.
Perception of sound by the ear/brain is a complex phenomenon as studies have shown. What appears to be more linear on paper may not be perceived as so. That said: my personal system is fully differential, triode, zero feedback, transformer coupled input to output. Even the output stage is set up as a diff. pair with a CCS "tail" (forced class A). There are many on the forum who avoid transformers because of their distortion. I happen to prefer their distortion to that introduced by capacitors. Each to his own.
"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln
This makes sense. A good transformer or choke will
out-couple even the best capacitors, and one can hear
that-- the reproduced sound is closer to the recorded
sound.
Transformers roll-off both highest and lowest
frequencies.
I think this "rolloff" concern is mainly a theory
that is technically correct, but has less practical
application in home audio.
I like an amplifier to sound true to the characteristics
of what is being played through it. In practical
terms, if you can get some decent output INTO THE ROOM
going down to 60HZ or so,. and can get highs to SATURATE THE
ROOM up to about 11.5KHZ, you're in business-- VERY good
business, sound quality wise.
The best approach to wiring and component construction
is to build for a wider practical bandwidth for both, then
worry about the parts and the circuit..
The actual parts in the circuit-- and the circuit itself
can exhibit rolloffs at both ends as long as we have that
60HZ-11.5KHZ range actually saturating the listening area.
Component quality easily trumps measured frequency
response here.
This is very hard to explain properly, but it works well.
In my view, highs aren't propagated properly into a listening
room by MOST of today's home audio speakers. Dispersion is
OK on some models, but if you want highs THAT WORK, then you
need large H.F. transducer surface area-- very large-- to
load your highs into the room properly and WITH ENOUGH ENERGY
for the room.
Enter the large panels, large ribbon tweeters, and horn-loaded
theatre-style units. Small domes may measure OK, but they aren't
the real deal.
Most people can't believe what an old S.E. amp with severe
rolloff after about 3800HZ can do with highs in a theatre--
The highs are there.. Clear, powerful and WAY above the amp's
rolloff. Why? The speakers are GOOD speakers... solidly
built transducers with large surface areas.
People theorize all the time about all of this-- to little
avail most of the time. If you're after real true-to-life
audio performance, then you have to go after the ideas and
components that actually deliver an honest performance.
The only thing that can out-couple a good transformer
is a good piece of wire-- that would be Direct-Coupling.
-Dennis-
.
Have Fun and Enjoy the Music
"Still Working the Problem"
Maybe I have the wrong speakers because I can hear the highs when they are not rolled off but then they go way when they are rolled off.
This file has a 3800Hz filter applied about half way through this short clip then, after a short time the filter is removed.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
hey Tre', when I was a wee lad, just learning how to design speaker enclosures, my pop told me of a demo he witnessed. This demo had an impossibly small, impossibly wrong properties, speaker making what appeared to be music down into the low bass. There was actually no low frequency content...the engineers putting on the demo had built a processor to create the harmonics of the LF content, rolling off in a precise slope. The listeners ears heard no LF, but their computers filled in that bit of information for them...
IOW, you can be fooled, either on purpose, or by accident...LOL
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
My apologies-- I should be more clear.
The problem with highs in a room is how
to get the H.F. energy to propagate well--
that is-- involve the whole room with enough
energy to drive that room....
I understand what you're talking about when
you refer to tones. In that we can and do hear
the different tones.
The problem arises when one tries to involve
a whole room. Small-surface transducers can
get the tone and bandwidth right, and at near
field, one can hear the tonal differences, but
these small-area transducers do not have the
power and dynamics to drive the whole room with
those tones.
One of the amps that I had that rolled-off so
severely was the Western Electric Model 91A.
With the right transducers, you could not want
any more high-end energy. A cymbal clash, for
instance, was complete despite the amp's limitations.
This only happens right when the correct Western
Electric transducers are used with their amp. It can
be stunningly good, and very accurate across a wide
bandwidth-- most all of human hearing.
Without those transducers, you'll not get the energy
that W.E. intended to put into a theatre audience.
With the recent S.E. amp revolution (started by Japanese
Western Electric Theatre component collectors), Japanese
collectors began resurrecting what Americans had forgotten
existed: movie-theatre sound. The Japanese wanted this
even in their tiny apartments!
Today, we're mostly trying to get the whole human hearing
range measured accurately inside components without any regard
for the room or the listener. Theatre people had to involve
the audience or sell fewer tickets. Japanese collectors,
tired of their own "perfect" measured equipment, snapped
up old American and German transducers, amplifiers and tubes.
Some even went so far as to use old Sprague electrolytic
capacitors, and Allen-Bradley Carbon-composition resistors--
things that add distortion to music. If the Americans did
it, then collect it and use it to sell equipment using it
back to them-- and be able to pay for collecting the "good
stuff", old theatre gear.
When a frequency rolloff involves hearing only tone, it is
immediately obvious. When H.F. CONTENT (should I say CUBIC
FEET of air affected by "highs"), is discussed, perhaps it
could be better understood that mild frequency rolloff is
not a factor, or it is ridiculously easy to correct if it is--
in the listening room..
Many people think that there's too much "highs" in a room
when the air volume affected by higher frequencies reaches
a certain upper limit. This is also true at the low end,
but it displays differently.
Amplifiers and transducers are at their best when they,
together, can drive a room completely acoustically. Good
equipment can deliver the entire human hearing range as
long as it has the speed and dynamics to get it done.
This can be done with amps that measure linear across
20HZ to 20KHZ. It can also be delivered accurately by
amps that are down at 80HZ, and put out almost nothing at
12 KHZ. What happens depends on the room and the trans-
ducers that are used in that room.
I realize that all this talk doesn't relate very much
to what we are told and sold today. Bandwidth and linearity
are cheap, accurate room coverage is costly, and involves
very few audiophiles.
It is possible, however, to experience the delights of
a good movie theatre system in the home. If you do use
large-area transducers, you will require that either the
amplifiers or the source components are going to have to
be rolled-off. Otherwise, people will tell you that
horn-loaded transducers are "yelling" at them.
What is more true-to-life? A tiny H.F. transducer being
driven beyond 22KHZ desperately stressing, straining, and
being driven way too loud in order to get some "highs"
into a room--
OR-- would you maybe prefer a nice theatre transducer
being driven to only 11.5KHZ-- or less than that--
smoothly and effortlessly, with terrific dynamics
delivering all the "highs" that one could possibly hope
for, stand or ever want?
Doing music reproduction effortlessly, dynamically,
and in a non-fatiguing way demands theatre-style gear.
It's the province of amplifier rolloffs, mini-watts
and large-area transducers.
Human hearing bandwidth is easily accommodated with energy
to spare. You don't need super wide bandwidth, or
extra claims to linearity.
What you DO need is to engage the
listening room fully.
Most source material and amplifiers are long on bandwidth
and tone. What they're short on is true-to-life dynamics,
perfect event-timing, and a sense of presence-- total room
coverage that converts the listening room as much as possible
into the recorded venue.
Large panels, theatre speakers, etc., are
designed to get this job done. What audiophiles
call "near-field" listening calls attention to
tone over much more important dynamic contrasts
in music.
There always will be different personal tastes
on how to reproduce music. Fortunately, most
people can recognize a good thing when they hear it.
-Dennis-
Now you are an expert on home theater audio?"It is possible, however, to experience the delights of
a good movie theatre system in the home. If you do use
large-area transducers, you will require that either the
amplifiers or the source components are going to have to
be rolled-off. Otherwise, people will tell you that
horn-loaded transducers are "yelling" at them."I showed you my HT above. Let's see yours!
Edits: 03/25/17
Hi Gusser!
The truth is, I'm not into the
internet like most of you are.
Perhaps you've noted this-- I don't
really know how to load pictures onto
the forum with the expected finesse.
I know-- what an idiot I must be! I can
take pictures, but haven't posted any.
OK, now you know about that, I'll see
if I can get some good ones-- that is,
after I get my taxes done.
My Home Theatre is simple-- something I
really enjoy without much fuss. A good old
Panasonic Plasma T.V. is all I have and
really need, although OLED T.V.s and the
new SONY XBR series, and that big Samsung
78-incher curved T.V. interest me.
I like Blu-Ray and DVD movies, and what
I can get off-the-air-- I don't pay per-
month on services I don't need.
Most of the system you might have seen
at audio shows-- a pair of my amps, my
big GPA transmission-line speakers, computer
audio, (library is Media Center-- J. River.
A P.C. running Windows 7-- modified to
eliminate all non-audio functions. I built
a 12VDC X 3 power supply to run the processor,
the sound card output, and the microprocessor.
All 3 are in one box, and all 3 are Linear-Tech.
regulated-- each has its own FWB rectification.
Output from each reg. goes straight into a choke,
then a cap, then more choke, and then a Foil-cap.
Power is routed into the computer using 3 Belden
12ga. shielded fire alarm wire pairs, cryogenically
treated. Bleeder resistors are across the outputs
internally.
I just used plain old Neutrik XLR connectors for the
12V runs. Makes it nice to unplug.
This P.S. made the whole thing into a superior sound
source. I wouldn't run any audio computer without it.
Blu-Ray player is Pioneer Elite's latest flagship,
their BDP-88FD. I really like this thing-- good
picture, and it sounds good. Audio goes into Berkeley
Audio Designs Alpha-DAC2 via SPDIF/BNC. Computer audio
gets into the same DAC via Berkeley's USB link, which
bypasses USB problems, and sports asynchronicity.
Recently I acquired a Pioneer PLX-1000 DJ turntable.
I was attracted to this thing because it has a nice
Direct-Drive base with fast stop and start controls.
I don't like belt drives because they delay and distort
music. A Direct Drive, DRIVES! I also like something
rugged that doesn't break easily.
I knew this thing would need help, so I called SME
up in Canada. Sent Alfred the stock tonearm-- I was
too lazy to tear it down myself, I think.
Alfred changed the tonearm wire to Cardas gold litz.
Al tossed the RCA connectors and ran the tonearm wires
all the way to the phono stage. I got that from Kevin
at K & K. I had a great design to build one, but had
to make it to RMAF first. I looked at it all over and
decided how to modify Kevin's phono stage. It got lots
of silver wire, more chokes, more small film caps, and
better RIAA parts from Rel-Caps Teflon stash. RIAA
resistors I changed later. THAT sure helped!
An Extreme Phono doughnut and mat really helped the
lowly TT, as did a new ClearAudio Maestro Ebony V-2
cartridge. Michael Fremer (at Stereophile) intimated
it to be world's most expensive Moving Magnet cart,
he was hinting at going further, but I read between
the lines-- got it, Dude! It's GOOD! (REALLY good, I
found out later). I love it more everyday.
I had a collection of Grado signatures, Shure items,
Stantons, Pickerings, Ortofons, Hanas, etc., but I'm
happy with the Clearaudio. Kicks ASS, and sounds
very dynamic, but lovely.
I'd say buy one....
All the sources go into a passive Ladder Attenuator, and out
to the 2 amps. The Alpha-DAC2 has remote volume control, but
I run the thing wide-open. Let the passive handle it-- better.
All levels match very nicely and close, so manual V.C. isn't
a chore.
It's a simple little system, but sounds very dynamic and
powerful-- movies certainly have lots of "bang" when called
for, and it's very clean, dialogue stays sharp through it all.
When I get rich, I'll get a huge Hi-Rez T.V. I'm waiting
for them to get better and more realistic in pricing.
I don't have any quarrel with introductory pricing--
development cosst get paid that way-- it's very good.
This system isn't Mega-Buck, but it's very good. Know
anybody with a deal on that new Samsung 78-incher,
curved screen model? It's dropped from $10,000.00 to
about $6900.00
I Still can't justify it.
Whoa! End of letter.... love your system!
-Dennis-
"It can also be delivered accurately by
amps that are down at 80HZ, and put out almost nothing at
12 KHZ. What happens depends on the room and the trans-
ducers that are used in that room."
The amplifier is a equalizer as well as a amplifier?
"It is possible, however, to experience the delights of
a good movie theatre system in the home. If you do use
large-area transducers, you will require that either the
amplifiers or the source components are going to have to
be rolled-off."
Yes, I see. That is exactly what you said.
We should all be using speakers that do not have a flat frequency response coupled to amplifiers that also do not have a flat frequency response.
Kind of like how when a LP is made they cut the bass and boost the highs and then in the phono preamp a reverse EQ is applied to get us back to flat.
Dennis, that is just brilliant.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I can't blame you.
I didn't say it was brilliant, did I?
Transducers aren't linear, listening
rooms aren't, and our hearing certainly isn't.
But many audiophiles and their engineers
demand it anyhow.
Perhaps I could describe it this way:
Go out in your yard and take a look at
the weeds and flowers that are there.
Some smell very nice, some look pretty,
and some are so good, you can eat them.
Deer, rabbits, and other animals love
them. But take a look at them-- they're
all different-- each and every one.
There isn't any Linearity at all! NONE!
But, it IS a good flower-- etc.
Now, let's find a LINEAR flower. This is
easy. Just go over to Wal-Mart, Target, or
whatever, and get some of those artificial
plastic flowers. Those Dudes ARE linear.
Why, they're all made alike-- if they're the
same ones. If they're different ones, then THOSE
are all like each other.
The problem is that they don't smell like
a real, non-linear flower, and Deer certainly
won't eat them. But they ARE linear!
OK- audiophiles like linear. And engineers are
oh so happy to accommodate their tastes. Whatever
the market desires can be engineered by someone.
Movie theatres, however, must cater to
natural occurrences in nature and recording scenes.
They also have to cater to the non-linear human
hearing in their theatre patrons.
You can sell tickets when you involve the
theatre-goer in the picture, the sound equipment
had better disappear....
That is how we got our ALTECS, JBL's, Klangfilms,
even W.E. and RCA theatre transducers. They weren't
designed for audiophiles, they were designed to
address our non-linear world and interface with
our non-linear hearing.
Surface area. Coverage area. That's the Fun-Factor!
That's all there is to it-- get it to mimic
the real, non-linear world as best you can.
-Dennis-
I have extensive experience with some RCA theater gear, and seen some comprehensive measurements done on them. Both the measurements and the listening experience indicates they are *QUITE* linear.I think you are on dog food...and not the expensive stuff they keep in the refrigerated section either( also excluding the more specialized low-ingredient count stuff ).
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Edits: 03/26/17
.
Have Fun and Enjoy the Music
"Still Working the Problem"
.
"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein
I might like your amp. A friend who finally gave up building his own amps would have built like you describe including a transformer at input as the phase splitter. He said it's the only way to get a symmetrical phase splitter. And he tried burning up tons of parts trying to build a great phase splitter.
Since my phono pre. and line stage have floating transformer outputs I have found (on the suggestion of Kevin Carter of K&K Audio) that connecting to the secondary side of the input transformer and using it as a CT grid choke gives the music a more dynamic and realistic presentation. As a bonus I can use the primary side of the power amp's input transformer as a galvanically isolated line out to drive my sub-woofer. As an aside, my DAC (PCM1794) is incorporated into the line stage. The balanced current output of the DAC chip uses two pairs of resistors to accomplish the I/V conversion and the balanced signal is routed directly to the grids of the line stage's diff. amp. No filter.
"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln
Why not? Make sure you observe
polarities/phase angles. Works fine!
-Dennis-
Hey Dennis, how is your K&K Trio phono pre treating you these days?
"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln
I modded it as it was built and
after, so it isn't stock. More chokes,
better RIAA, some super-quality small caps
in all the right places, silver wire in
the right spots, re-routing of some wiring
and the power choke mounting area. More local
power-usage areas cleaned-up and made more dynamic.I like it now. There's plenty of power on
board to clean up and apply better,
RIAA is separated into two smaller
networks, feedback isn't a problem, and
gain is just right-- kicked up one notch
in my case..I ran several cartridges into it, but the
new Clearaudio Maestro Ebony V-2 came up
with ALL the goods musically-- a first for
me-- I have never completely liked any cartridge,
MC or MM until now....It's a good phono. I run it right into amps
thru a passive Ladder attenuator. Plenty of
Kevin-style drive gets it done.I'll just say it's a Keeper. We're also
messing around with Liberty Audio's solid
state phono. I don't have it yet but have
solid love/likes from Tom Thomas. I thought he
should have one, he surprised me and got it!At first he was cautious about saying
anything good about it. I had read Stereophile's
review on it and had spotted a few things that I
thought I liked.It turned out that Tom called several days
later and said the Liberty was really good.
It's Stone Stock. I think of doing a show with
2 turntables, Disc-Jockey style. With two
DIFFERENT phono preamps, and two DJ style TT's..This would get two things done: (1) make
for a fun time playing L.P.s-- no time
delays cueing-up. (2) two different,
but accurate, results. Sometimes using a
solid-state front-end to drive vacuum tubes
is really good. My Alpha-DAC2 proves that
every day to my own, and others, never-ending
delight. But sometimes tubes driving tubes
"locks-in" older LP's-- such as 1960's major
recording labels-- hey! Why not have both?.Most of all, Kevin's phono now kicks-ass
dynamically, and that's rules one, two, and
three with me. That's also what I am about with
recommending the Liberty. Tuning phonos is easy.
Good tone is a snap for good tuners.Getting real, true-to-life dynamics is
rare, and that quality is what made me
want to play with both of them.More on the Liberty as it develops, and
when I can lay my hands on one....The K & K TRIO is a winner. I have
played it enough by now to recommend it..-Dennis-
Edits: 03/26/17 03/26/17 03/27/17
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