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The road ahead

209.137.226.169
Posted on June 23, 2012 at 22:03:41
tube wrangler
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Joined: January 29, 2007
 Their science had become a religion-- driven by accepted rules and formulas rather than by reality actually presenting itself in the form of new or more useful ideas which existed because they worked better.

Their science, as they had believed and proved it had molded them into an inferior state mentally, physically and spiritually so that they had become incapable of discerning truth-- their ideas of truth were always subject to consideration of sources, rules and formula information, not whether anything was actually true or not in and of itself.

Common Sense thus, was always trumped by their answering to their science religion-- Common Sense was not considered proven by rule or formula, so it was always discarded as "gibberish", coupled with more and more demands for more science, rules and formulas. People who would not conform to these demands and deliver the science, rules and formulas desired were dismissed, discarded, and labelled as "fraudulent".

One day, they came to a Great Divide. The road they were on suddenly morphed into TWO roads: One led over a Cliff-- but this was just out-of-sight and over the Horizon. The other road violated all of their science religion as it had no rules or formulas and offered no proofs either.

They studied their science-religion very carefully before they made the decision of which road to take.

It was at this point that they decided to take the road that led over the Cliff-- having concluded that the other one offered no science, rules or formulas..........

---Dennis---





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RE: The road ahead, posted on June 23, 2012 at 23:36:19
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 Scientific formulas describe "reality actually presenting itself".


Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: The road ahead, posted on June 24, 2012 at 04:07:17
tube wrangler
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 That's as good as far as it goes for sure.

What we call Science is actually built-up-over-time-- a compendium of man's observations over that time-- things that have mostly worked SO FAR.... and rules and formulae designed to allow one to repeat those observations in another setting. We hope, in such cases, that new information or things changing haven't yet rendered that science obsolete.

We know as a fact that ALL science WILL at some point-- prove obsolete, incomplete, or just downright wrong under the microscope of newer and better observations. Time marches on...

We need science, and we all use it. We then try to apply "the Scientific Method" in order to extend whatever line of reasoning is present-- and to try to prove or disprove something about it.

If truth be told, people really don't have completely original ideas. Guys like myself-- when allowed to think freely and independently-- must also admit that our ideas are partly a result of scientific theory, past people's ideas and inventions, and partly a result of older observations.

The most successful world is that one in which an individual is able to think freely, and apply what a project needs honestly and freely, using all that is at His command, and that does include scientific theory and application.

My earlier post was about that circumstance where people separate out only the rules, formulas, and the formerly proven, and then postulate that those are the only relevant parameters present, and then call that narrow-minded approach "science".

When used in this fashion, "science" becomes a mere religion of sorts and ceases to be wholly scientific.

Instead of being a useful tool, when rigorously applied as a religion, "science" becomes merely another stumbling block to scientific progress.

Our best efforts have been applied whenever the individual has been free to apply what of known Science truly applies to what he is devising, and further-- has been left free to go beyond that-- has been saved harmless from unneeded harrassments-- in order to apply the imagination in ways that will benefit the undertakings at hand in a more complete and desirable fashion.

There's nothing wrong with Science. There's plenty wrong with making it-- or any other one thing-- a religion at the exclusion of all else, rendering needed accurate assessment and reasoning at best incomplete-- or at worst a disaster in the making....

It is a fact that whenever men make mistakes that they didn't need to make-- or should not have made-- in every case there had been people present-- if they had been free to speak-- had known what was misapplied, could have, and would have saved the men from making their mistakes, and from the consequences of those mistakes.

True progress is a wedding of only the science that should be applied to the case at hand-- together with the culmination and application of original thinking about the NEEDS of the project that is at hand.

---Dennis---

 

RE: Errrrrrr, posted on June 24, 2012 at 05:08:37
Neff


 
Use basic laws of physics and then experiment. I think most of us DIYers perform that here at AA. I cheat a lot by using others ideas at this site. I wish I had more time to experiment more myself. I either work my job with some travel, date women or sleep. But, I like good tunes.

 

RE: The road ahead, posted on June 24, 2012 at 08:22:04
Palustris
Audiophile

Posts: 1243
Location: Cape Cod
Joined: September 12, 2008
 I'm an agnostic when it comes to audio.

 

RE: Errrrrrr, posted on June 24, 2012 at 09:50:50
tube wrangler
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 Love those good tunes!

--Dennis--

 

RE: The road ahead, posted on June 24, 2012 at 10:37:36
lakerfan
Audiophile

Posts: 354
Joined: April 9, 2002
 I love good tunes . Please procure me a pair of AVVT 2A3 mesh plates. Your connections reach far and wide. Do this for me as a music lover, not as a vender. :-)

 

RE: The road ahead, posted on June 24, 2012 at 11:48:28
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002

"True progress is a wedding of only the science that should be applied to the case at hand"

I love free thinking but the above equation for the -3db down point of a low pass filter can not be ignored. It is not a religion. It is a formula that describes (very accurately) what WILL happen in the real world.

If you drive 70pf of Miller capacitance with a source impedance of 50k ohms you WILL have a -3db point of 45495.90537Hz.

There are other formulas that will tell you that the phase WILL be disturbed all the way down to 4549.590537Hz

This IS what WILL happen in REAL life, not just a "theory" or a "religion" but REALITY.

I encourage you to think freely but you have to deal with reality at the same time.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: The road ahead, posted on June 24, 2012 at 11:50:15
tube wrangler
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Posts: 1363
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 All 'ya gotta do is call me! Check at my website for phone #.

--Dennis--

 

RE: The road ahead, posted on June 24, 2012 at 11:57:42
tube wrangler
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Posts: 1363
Location: USA
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Good advice for anyone. I wouldn't, however, make too many assumptions about bandwidth realities in my applications-- you haven't seen or tested these items.

Some of my application info. is proprietary, but I think you can find out from others that your figures are wildly-- not applicable to this particular item.

While the formula is correct, the assumptions being used to insert figures into that formula-- in this case-- are incorrect.

---Dennis---

 

RE: The road ahead, posted on June 24, 2012 at 12:24:00
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 "Some of my application info. is proprietary, but I think you can find out from others that your figures are wildly-- not applicable to this particular item."

I very seriously doubt what you have said.

Having said that, I was speaking not about the frequency/phase response of the amplifier as a whole. Just the response of the filter that is very much reality and has to be dealt with.

How you may or may not go about correcting this problem after the fact is not my concern.

I feel that it is always best to avoid this types of problems to start with rather than compensate for them after the fact.

"While the formula is correct, the assumptions being used to insert figures into that formula-- in this case-- are incorrect."

The output impedance of your 7b4 driver stage is easy to measure or calculate.

The Miller can be easily calculated once the interelectrode capacitance's and the mu are measured, so your use of the term "wildly" is not called for.

If my numbers are off, please feel free to correct me and give us the correct numbers.

In any event, with a 7b4 driver tube with a plate resistor the output impedance will be too high for a DHT's Miller capacitance. The resultant low pass filter will have consequences in the audio band. There's just no way around that.

Tre'


Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: The road ahead, posted on June 24, 2012 at 13:43:50
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
You're not entirely wrong here. Unfortunately, it's your emphasis on only one part of an entire design that is way over the top.

The Miller Capacitance of a DHT is a very real parameter, as you state, and it must be considered, as you correctly point out.

When I build an amplifier, that design is supposed to replicate a studio recording in the best way that I can build.

ALL amplifiers are sets of compromises, and in all cases, one item in a design comprising many parts and calculations may have to be changed in one or another direction-- but not too far!-- in order to allow for another important consideration-- to NOT go ignored!

In this case, I'm not willing to give up the transparency and speed of a High-mu, low plate current driver just to satisfy a desire for the ultimate in powering Miller Effect inside a DHT, although I do consider DHT bandwidth very important, as I do slew rate.

I fully understand the truly awesome performance that comes from a high-mu, low plate current driver-- as opposed to higher-current stages which are much harder to drive themselves AND THUS SEVERELY COMPROMISE THE SIGNALS COMING INTO AN AMPLIFIER FROM MUSICAL SOURCES-- that are used to drive amplifiers..

In the case of the High-Mu driver stage, it is very important to avoid overloading its output... and I recognize that you have noted this.

Accordingly, I allow wide voltage swings with high-impedance loading on the driver stage output. Certainly, the Miller Effect of the DHT being driven is also loading this stage, but I am able to get the bandwidth I need anyhow by carefully evaluating all of the factors that impinge on it.

So, the simple calculation of the filter network that is always part of a driver stage's loading, is not the only consideration there.

In your own case, I would be cautious of overestimating Miller Effect in DHTs-- different brands are very different, and plate currents and voltages that are used in a circuit operating the DHT are also contributors to the same tube exhibiting DIFFERENT Miller Effects under different operating conditions.

Miller Effect Capacitance is NOT a numerical figure that one can simply plug into a formula-- it changes with operating conditions, and with brands of tubes.

Overall Balance is everything.

In this case, Miller Effects have been recognized, but the much larger other factors present in the circuit design have also been considered-- and kept close to THEIR optimums-- all the while still keeping in mind the limitations imposed by Miller Effect, and not going overboard on that, either.

We want ideal TOTAL loading-- of the driver stage as much as is practical so that Miller Effect-- which really isn't that bad at all-- is really the only thing left that negatively affects driver stage performance.

By using such a comprehensive, overall approach, the Miller Effect that is present here simply isn't a problem.

The final result of an entire amplifier's performance is what I'm after, and in this case I have it right where I want it.

---Dennis---

 

RE: The road ahead, posted on June 24, 2012 at 14:04:44
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 The Miller capacitance of a tube is the (static) grid to plate capacitance multiplied by the mu of the tube plus the (static) grid to cathode capacitance.

The output impedance of a resistor loaded driver stage is the plate resistance (at the operating point) in parallel with the plate load.

You used a lot of words to say very little.

"Certainly, the Miller Effect of the DHT being driven is also loading this stage, but I am able to get the bandwidth I need anyhow by carefully evaluating all of the factors that impinge on it. "

If you would just say what the output impedance of you driver stage is (and how you arrived at that number) and the Miller capacitance of your output tube we could settle this.

I don't see how the output impedance of a resistor loaded 7b4 driver stage can be low enough to prevent the Miller capacitance of a DHT from causing problems within the audio band.

You say you have done this, I say you can not have done this.

Unless you are willing to explain, in plain English, how you prevent this low pass filter from negatively effecting the audio band I will go on believing that it does.

I think that is fair and reasonable.

BTW You have said in the past that your amplifiers start to roll off at 15kHz. You also stated that with NOS tubes this roll off can start as low as 9kHz do to the increased Miller of some of the older tubes.

That sounds like an admission that the high output impedance of your driver tube is causing (in all cause, even with the new tubes that have lower Miller) problems in the audio band.

If, when you say that you get "the bandwidth I need", includes roll off and phase disturbance within the audio band, I would propose that the bandwidth you need may not be the same as the bandwidth myself and most everyone else needs.

Tre'


Have Fun and Enjoy the Music
"Still Working the Problem"

 

I dub thee Esoterica---NT--, posted on June 24, 2012 at 15:08:42
elblanco
Audiophile

Posts: 2153
Joined: August 20, 2004
 kjh

 

Dennis ....., posted on June 24, 2012 at 16:16:45
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 You state this above :

"The final result of an entire amplifier's performance is what I'm after, and in this case I have it right where I want it."

That says it ALL, and it sure SOUNDS that way to me and many others who listen.

I respectfully suggest you do not waste precious time on "non issues". Your circuit and your most thoughtful product implementation speaks so eloquently for itself, and it always has !!

Jeff Medwin

 

RE: The road ahead, posted on June 24, 2012 at 19:11:16
tube wrangler
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Posts: 1363
Location: USA
Joined: January 29, 2007
 All tube amps have some rolloff.

Tubes themselves have a lot of it. Just broken-in tubes often greatly outperform tubes with more hours on them.

A good question would be "why do we bother with tubes at all?".

I think we like the transparency INTO the musical layers of a soundscape that tubes are better at, than are more mathematically flat-curved components.

No one here would argue that DHTs have perfect, flat powerbands. We all realize that pentode operation or BiPolar S/S devices, or even Mosfets can cream all DHTs for bandwidth.

The arguments will go on for millenia. Some even think that DHTs should be "corrected" by circuitry to deliver more "flat" response. NO! ALL devices sound BEST when NOT pushed, molested, or tinkered with in any way!

My own experience is that once a certain threshold of information that the human hearing system needs to form a certain sonic picture is reached-- then adding more bandwidth to that threshold produces nothing more of value.

All of us have experienced what happens when you make a tape recording of a tape recording. The amount of complete sonic information that the human hearing system needs is not met in the second copy, so the result is a drastic drop in fidelity in the second copy.

Then, also-- we know what happened with the older CD players. Although these had plenty of bandwidth and low distortion specs, they fell VERY short on usable sonic information that the Human Body can use--and simply sounded like trash when compared to vinyl systems.

At this time, we are also experiencing this same phenomenon in a sort of reversed way-- in Digital computer audio.

On LESSER systems (ones that, like the tape recorders of old, lose too much information THAT THE HUMAN BODY CAN USE)-- sound better when High-Resolution material is played, rather than the old Redbook CD standard-- 16 bits @ 44.1 KHZ.

YET-- when really excellent equipment is used to play a well-recorded CD that is only 16/44.1-- it sounds OUTSTANDING! AND, higher resolution material may very well NOT sound any better at all-- in fact some of it is MUCH WORSE!

Well, what is going on here? It's simpler than it appears: once the Human Body gets what it actually needs to form a sonic impression completely, then THINGS WORK, and NOTHING MORE IS NEEDED, and in fact, SHOULD NOT BE PROVIDED..

Take things BELOW that level, and things rapidly fall apart musically, regardless of specs or bandwidth.

SATISFY that level, and anything that you do BEYOND that level will produce very little-- if any-- improvement.

The moral of the story is just like life itself: DO WHAT ACTUALLY WORKS.

---Dennis---





 

RE: The road ahead, posted on June 24, 2012 at 20:30:33
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002

"Many typical audio tubes are good to 20 or 30 MHz with proper RF circuit design, assuming that you are actually making an RF amp. The old Metal 6L6 will work on the 20 meter ham band (14 MHz) and put out considerable power. Even the worst type of tube should cover up to a few MHz, so frequency response of the tube itself is not a factor in an audio amp."

From tubelab.com answering the question "Is there any available data sheet that shows output tubes' frequency response?"



You know Dennis, you really do live in your own little world.

Your post did not answer my question in any way.

It did, however, give us insight into your thinking.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Deja vu, posted on June 24, 2012 at 21:18:56
mach1
Audiophile

Posts: 359
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 Your over inflated sense of self importance beggars belief. It’s a relief you don’t design aircraft.....


http://db.audioasylum.com/mhtml/m.html?forum=tubediy&n=139635&highlight=God+complex&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fforum%3Dtubediy%26searchtext%3DGod%2Bcomplex

 

There needs to be a showdown in the road......, posted on June 24, 2012 at 21:28:03
lektrik
Audiophile

Posts: 377
Joined: May 31, 2002
 To me, talk is just that, 'talk'. I'd like to see (hear) a 'showdown of the ideas' and put one of the sides to rest, kinda. (Its not that either of you are totally wrong.) That's one of the shortcomings of this online forum. This 'talk' can go on forever. Break out the 'guns' (amps) and put this thing to rest.

When the word 'religion' is used, the first thought that comes to my mind is 'yuck', next is dogma, indoctrination, stiffnecked, hardhearted, the systematizing of error, unyielding, conscience seared with a hot iron (soldering iron?)......anyway, you get my point. God doesn't like religion and neither do I, concerning anything. IT AIN'T GOOD. When you become religious about anything, you have shut off the learning aspect of it. I believe neither of you are totally religious, you're both intelligent, but someone has to be wrong at some point. I vote for a showdown.

L.D.

 

RE: There needs to be a showdown in the road......, posted on June 24, 2012 at 21:44:32
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 The showdown would not be between two amplifiers.

Shortcomings at one stage of an amplifier can be compensated for in the next stage.

What I'm talking about is the low pass filter created between the output impedance of the driver stage and the Miller capacitance of the output tube.

This low pass filter is real. There is no need for a showdown.

Dennis has already admitted that his amplifier suffers the effects of this filter in the audio band.

I would say the showdown already happened.

Dennis thinks his amplifiers sound good as they are.

"My own experience is that once a certain threshold of information that the human hearing system needs to form a certain sonic picture is reached-- then adding more bandwidth to that threshold produces nothing more of value."

I believe he should take some steps to mitigate this problem.

If he did, I believe he would find that his amps would sound even better to him, assuming his hearing will allow for that.

But this back and forth has never been, for me, about how his amps sound.
That is too subjective. For instance a lot of people think that 1970's Japanese receivers and Bose speakers are great.

This back and forth is about Dennis' amps, that he claims are the best ever built, yet they have at least two real world flaws in their design.

Oh, and his use of junk science to explain it away.

Do you remember the question, "What is feeding the circuit when the diodes are not conducting because the input choke does not meet critical inductance that would keep the diodes conducting in a constant manner"?

The answers were always full of junk science and the question was never really answered. BTW The answer is....the last cap in the filter.

That is the opposite of the stated goal of his power supply design.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: The road ahead, posted on June 24, 2012 at 21:46:01
danlaudionut
Audiophile

Posts: 4772
Location: Schenectady
Joined: June 6, 2002
 Dennis

I agree on some things and disagree on others.

>> All tube amps have some rolloff.

Disagree
You CAN design for 10-200KHz bandwidth
and so rolloff would be negligible.

>> Just broken-in tubes often greatly outperform
>> tubes with more hours on them.

Agree

>> ALL devices sound BEST when NOT pushed,
>> molested, or tinkered with in any way!

Agree

>> All of us have experienced what happens when
>> you make a tape recording of a tape recording...
>> the result is a drastic drop in fidelity
>> in the second copy.

Disgree
I had excellant 3 head tape decks back in the 70's
that had adjustable bias so when I made copes they
were indistinguishable from the originals.
A well recorded tape will sound better than
well recorded CDs when each are played on
equally high quality equipment.
Vinyl beats them both though.

>> when really excellent equipment is used to play
>> a well-recorded CD that is only 16/44.1--
>> it sounds OUTSTANDING!

Agree
I use NOS DACs because (as stated above)
they don't "molest" the signal 8^D

>>> higher resolution material may very well NOT sound
>> any better at all-- in fact some of it is MUCH WORSE!

Agree
Because they tend to "molest" the signal.

>>> once the Human Body gets what it actually needs
>>> to form a sonic impression completely, then
>>> THINGS WORK, and NOTHING MORE IS NEEDED,
>>> and in fact, SHOULD NOT BE PROVIDED..

"There's the rub" (Shakespeare)
But that is different for everybody.
I have hearing out beyond 20KHz so
my level of HF energy needed is less
than those who only hear to 15KHz.
My room may be different ...
My speakers may be different ..
My musical taste may be different ...
My listening volume may be different ...
So to even suggest that one product,
no matter how well designed it is,
can satisfy everybody is foolish.

>> DO WHAT ACTUALLY WORKS.

I would add - "for you" to that.
DO WHAT ACTUALLY WORKS FOR YOU.

DanL



 

RE: The road ahead, posted on June 24, 2012 at 22:13:10
tube wrangler
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Posts: 1363
Location: USA
Joined: January 29, 2007

Some really astute observations here!

Ok-- you wonder what I'm thinking about this:

"All tube amps have some rolloff". I should have said all naturally operating tube amps have rolloff. I left out the application of negative feedback, the application of controlled positive feedback, and the reduction of frequency peaks which will result in frequency troughs appearing larger because the peaks have been reduced by comparison to the troughs. I wouldn't recommend any of these things to anyone who is actually trying to listen to music, however.

"I had excellent 3-head tape decks back in the 70's"...... Agreed, I did also-- The large Ampexes running one-inch tape at 32 IPS, the Revoxes, The commercial 10 3/4 inch Sonys and the large Tascams, etc. These were all superior to the best vinyl-- it was badly compromised by dynamic compression, which included the infamous RIAA curve. It still sounds OK at it's best, but it's no longer anywhere near the standard today. Can you make-- today-- a really great L.P.? You can, and some do! I have no argument there at all.

And, I agree with you some more. No one appliance is going to please all the women in the kitchen. They're going to get what they like regardless of you or I. We can, however, seek to allow maximum dynamics to get through, to allow max. transparency to get through, and to build amplifiers that can actually drive speakers properly. We can do a lot.

After we've done all that we can, the Owner is still the Boss.

---Dennis---







 

RE: Deja vu, posted on June 24, 2012 at 22:26:18
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
 Awww.. Heck! No, I don't care whether I'm important at all.

I do, however, like things to work like they should.

I did have a good time designing Stand-Up Jet Skis for racing, and I did OK with Motocross and Snowmobiles. None of them broke much-- they were OK-- others thought they wanted to ride them instead of what they had-- most of the time, if I remember that correctly.

I never thought I was important, but I did have a lot of fun! Like I said, my stuff usually never broke. It just went faster, accelerated faster and handled better. It was also MUCH safer.

But, I digress. I did crack-up a Yamaha SuperJet that I had redesigned. It seems I ran over an underwater rock shelf which ripped the bottom out-- at high speed. Now THAT wasn't very smart! That was in S. California, which I still love to this day, as many know!

The guys said it was spectacular when I bounced across the water, having been ejected. That wasn't done to make me popular, however!

Oh yes, I forgot to mention the Surf Machine near San Onofre. It seems the hot water from the power plants creates an escalator current alongside a giant rock-- it takes you right out-- just like a river, and then you can paddle across to the middle of the bay and ride the waves back in.

Now, THAT was fun.... I think I may be incurable-- I just like good times, things that work well, and good people.

---Dennis---

 

RE: There needs to be a showdown in the road......, posted on June 24, 2012 at 22:46:36
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
 Well, I've done all I can!

The showdown is-- as usual-- at Denver's RMAF 2012 in October.

No one "wins" it-- nobody expects to-- it's a Hotel after all, and setup time is severely limited.

One CAN, however, spot great equipment in several of the demo rooms at these shows.

All of the exhibitors at these shows are doing it for you. Oh yes, if he gets LUCKY-- one may get to sell something once in a great while.

Denver in October! It's fun, and it's nice. One might accidentally find something he likes in there.....

In any case, there's no harm done, now is there?

---Dennis---



 

RE: The road behind, posted on June 25, 2012 at 00:53:19
Frihed89
Audiophile

Posts: 13165
Location: Copenhagen
Joined: March 21, 2005
 Does your o-scope always agree with your ears?
Observe, before you think. Think before you open your yap. Act on the basis of experience.

 

RE: The road ahead ....is a cliff with a trail of lemmings following you , posted on June 25, 2012 at 08:12:22
GEO


 
This is about as nonsensical a post as I have ever observed on this board. 'Fund' your own forum like some of the other manufactures and the disciples that want to adopt your teachings can take advantage of your knowledge and implement your ideas in that forum and you can spare the rest of us. In your mind, science has no value and that is perhaps one of the most ignorant concepts I can imagine. Not paying any attention to science can lead to someone getting killed building an amp. Ignoring science and convincing people that it is frivolous is irresponsible and dangerous.

 

RE: The road ahead ....is a cliff with a trail of lemmings following you , posted on June 25, 2012 at 10:45:48
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 "Not paying any attention to science can lead to someone getting killed building an amp. "

or driving across a bridge or flying in an airplane or any number of things that Dennis does every day.

He has no respect for science yet relies on it daily.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: There needs to be a showdown in the road......, posted on June 25, 2012 at 11:52:13
Ralph
Manufacturer

Posts: 2188
Location: Minnesota
Joined: April 24, 2002
 Tre and I have locked horns plenty enough in the past, but mostly over semantics rather than anything else.

The math is the math though, and try as one might to ignore it, the fact of the math remains and does manifest in any design. Sounds to me like Dennis hand-picks his tubes to get bandwidth, if he does any measurements.

I asked a question of Dennis in a thread below which went unanswered. It had to do with heating in the VC of a loudspeaker. Maybe he could answer it here....

If not, I have to assume that the VC heating thing isn't real.

I found that there are different ways that an amplifier can drive a speaker. It depends on output impedance and the like, and has a lot to do with how the speaker is designed. Once I sorted out some of the differences in the design rules I wrote a short paper explaining what was going on. I have posted a link.

The paper ignores the current-drive method as that never really developed into what I would call a paradigm. But there is plenty of evidence for the Power Paradigm and the Voltage Paradigm is well-known. Most any SET, BTW, is a Power Paradigm device. I wonder if this is what Dennis was talking about with his VC heating comments?

 

The road ahead is paved by success. Where things work and fulfill needs, money follows., posted on June 25, 2012 at 14:26:42
Chris O
 It doesn't matter if consumers understand physics and math.

If you got the product they want, they will buy it. And if your competitors don't believe in your methods, they can't copy it. You will have a complete monopoly and be a billionaire.

Very few people understand the physics at play in the construction of something like the new Intel Ivy Bridge 8 core microprocessor (which, among other things, contains 2.27 billion transistors), they just know that their porn loads really fast.

 

RE: The road ahead ....is a cliff with a trail of lemmings following you , posted on June 25, 2012 at 15:09:31
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
 What a bunch of desperate ASSUMPTIONS. Good grief.

Nobody is throwing out science-- we couldn't operate without it!

What I'm using is a BALANCE. I object to things that are OUT of balance only because they don't work as well as they should, and we can--and do-- do much better. That's all there is to it...Come on!! It's SO SIMPLE!

---Dennis---

 

RE: The road ahead ....can be bumpy...., posted on June 25, 2012 at 17:56:03
lektrik
Audiophile

Posts: 377
Joined: May 31, 2002
 Dennis,

I deal with ungodly 'religious' people all the time, so I understand your religion analogy here. Another descriptive word I left out in my previous post which is synonymous with religion is 'accusation'. You had better not 'misspeak' or they'll nail you to a cross (or at least try).

I'd been made fun of by one of your AA 'accusers' years ago because I was new to this hobby and I posted a question, but didn't ask it right. I don't remember what the problem was, but it was something simple like using a wrong word/terminology to describe what I was trying to find out the answer to. I see that nothing's changed with this person. Too bad because I know they're intelligent enough to be ultra helpful, but they're religiously bent on making sure everybody 'follows the rules'. I might think they have something worthwhile to consider to if they'd present themselves in a respectable manner and not belittle those they disagree or find fault with.

I know you can't go outside the law of physics, even spiritual forces must operate within that law. Its set and can't be broken. Manipulated? Yes, but still within the law's boundaries. That's where the paranormal field comes in, but that's another subject. Not 'all' science is truth. Some is just conclusive facts that serve as an explanation for something happening, not the whole 'truth'. Sometimes these facts become 'accepted' and are served to everyone as truth (but I speak of things concerning another subject).

As you said, I think there are things that we don't know everything about, but I'm a 'show me' guy and then I'll evaluate and come to 'my' conclusion. There can be a world of difference between 'fact' and 'truth'. I try to get as close to the truth as possible, but hell, I'm a person and I'll make mistakes. I'm not afraid to make mistakes, but I'm getting better at making less of them.

Anyway, I do like how you approach a subject and how you handle yourself when others not-so-respectfully disagree with you. I would consider what you have to say because of your approach. Not that I even understand some of the things you speak of, but I like your friendly demeanor. Don't ever bother defending yourself, you don't have to.

L.D.

 

at RMAF, posted on June 25, 2012 at 20:22:18
GEO
Audiophile

Posts: 2699
Joined: April 7, 2000
 Post simple answers to simple questions on a whiteboard in hotel room at the show..... The system can be a 'static' setup as the sound of the amp is not what is leading to these ridiculous threads and you know that.......

 

RE: at RMAF, posted on June 25, 2012 at 21:36:40
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 Geo.,

People come to the show to meet the Manufacturers, but most of all, to see and hear the equipment, as best as they can. Posts up here mean zilch, audio performance is what really counts the most.

Jeff Medwin

 

RE: at RMAF, posted on June 26, 2012 at 04:38:11
GEO
Audiophile

Posts: 2699
Joined: April 7, 2000
 How mnay times does some one have to say that this stupid thread is not a criticisim of Dennis' amps. You can't be that dense.

 

RE: The road behind, posted on June 26, 2012 at 04:45:24
GEO
Audiophile

Posts: 2699
Joined: April 7, 2000
 Do you think everyones hearing is exactly the same? Again, no one is arguing about the sound of an amp. Its about BS made up engineering. Dennis would have been better off not to open his mouth other than to say "I design my amps in a way that is pleasing to me and my customers".....instead he brings up nonsensical made up engineering terms and criticizes the way other amps are built. Observe, don't think....I hope that is not advice you share with kids.....observe your friends drinking....don't think about it....join in.....no wonder in many parts of the world, thinkers pose the most threat and are the first to be round up and jailed......

 

RE: The road ahead.., posted on June 26, 2012 at 04:47:58
deathtube 667
Audiophile

Posts: 540
Joined: November 25, 2010
 Dennis,

Great essay. It speaks to the current state of the AA tube forums.



The critics are speaking without merit based on false assumptions and not real building or listening experience to modern tube circuits.

dt 667





 

RE: at RMAF, posted on June 26, 2012 at 06:32:25
RPMac
Audiophile

Posts: 231
Location: So. Mississippi
Joined: January 3, 2005
 I'd be willing to bet that to most of us, it is ALL ABOUT the sound of the amps we build and listen to.

 

RE: The road behind, posted on June 26, 2012 at 06:54:08
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 Geo,

You state "Again, no one is arguing about the sound of an amp. Its about BS made up engineering."

Lets just say, Dennis has produced the best sounding 2A3 amp ever made, (I personally think it is the best 2A3 amp "I" have ever heard.)

Now, he offers us a circuit and design description that differs from our normal way of thinking about circuits, that we all learned. Could it be that he is correct, and we were somewhat incorrect in our thoughts?

If so, what you are terming as "BS" / "made up engineering" is in reality, the truth. His amp's performance handily demonstrates to me - quite ably - that Dennis KNOWS the truth.....of how to get really good 2A3 audio performance.

Hell, I'd want to carefully listen to what the designer has to say, just to improve upon what I am listening to at home !!

Seems that his total thought pattern and approach, is in fact superior, and obviously not inferior as you propose.

Jeff Medwin

 

RE: at RMAF, posted on June 26, 2012 at 07:05:15
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 Agree.

Additionally, Geo (1) has never heard Dennis's amps, (like about ALL the criticizers I see up here), and (2) he seeks to conveniently dismiss the MOST obvious evidence - that which proves he stands on a weak foundation.

Yes, its ALL about the sound. Who cares if it uses a banana peel for the finals!! Results count.

Jeff Medwin

 

I should have said, posted on June 26, 2012 at 10:53:19
Frihed89
Audiophile

Posts: 13165
Location: Copenhagen
Joined: March 21, 2005
 "observe before you think". Thanks.

On another topic. This is just an another round of the debate between Dennis and Tre. I think Dennis is baiting him, frankly.
Observe, before you think. Think before you open your yap. Act on the basis of experience.

 

Hey Tre!, posted on June 26, 2012 at 13:31:56
DanK tubes
Audiophile

Posts: 372
Location: California
Joined: November 9, 2004
 I hear you. It boggles the mind how these threads just keep coming up. No one ever mentions how the DC coupled 2A3 amps in question sound, the arguments are always about the unproven claims of "performance", ridiculus invented "scientific" terms, unverifyable testing results and procedures, and junk science. I don't understand how Dennis and Jeff can't see that no one ever questioned how their amps sound. I'm really starting to believe this is some type of marketing scheme to gain product visiblity.

That said, have you ever thought about building one? If you look at SET amps in general, their distortion numbers are horrible. Yet people seem to love their sound. I know I do. Maybe this is another case where poor distortion sounds good to some people. At times I've thought about building one of them. Even thought the facts are that the HF will be rolled off from Miller effects, and that peuney sub-critical choke loaded power supply won't regulate worth a crap. Maybe all that signal filtering and distortion sounds good. High gm drivers allow for more current, but tend to pass more RF. Maybe that 12ax7 just doesn't allow higher freqencies to get through. I don't know, but sometimes I think about trying it out just to see.

I just long for the day when people stop all the nonsense claims about these products. I've given up on arguing with Jeff about it. In the end he'll just resort to namecalling.

Dan

 

RE: The road ahead, posted on June 26, 2012 at 15:55:51
Stuben
Audiophile

Posts: 291
Location: Guber Ohio
Joined: December 30, 2005
 Tube,

That must have been some good stuff;>)

Your writing is too nice to trivialize with debate.

If everyone uses their ears and leverage science to that end...no issues..

Oh...was that an opinion?

Stuben

 

Dolt, posted on June 26, 2012 at 15:56:28
GEO
Audiophile

Posts: 2699
Joined: April 7, 2000
 move on.

 

RE: at RMAF, posted on June 26, 2012 at 15:57:24
GEO
Audiophile

Posts: 2699
Joined: April 7, 2000
 you have no idea of the origins or this stupid thread. probably started two years ago. move on.

 

RE: at RMAF, posted on June 26, 2012 at 15:58:48
GEO
Audiophile

Posts: 2699
Joined: April 7, 2000
 I have not heard the amps therefore I can't critiize the sound of it. You are right. Dig through these post and point out where I criticized his amp....nimcompoop.

 

RE: at RMAF, posted on June 26, 2012 at 16:19:02
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 'You can't be that dense.'

I beg to differ.

 

RE: at RMAF, posted on June 26, 2012 at 16:40:32
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 It is all about the sound.

When things are done right, the sound will be better.

It might not be recognized as being better.

One needs to know what real instruments sound like to start with before they can judge if a system is doing a good job at reproducing.

Leave the Miller not fully driven.....leave the cathodes not fully bypassed and the system will not be doing a good job at reproducing.

Will some people like or even love the way that sounds?

You betcha!

Let me be clear.

If God Almighty Himself said that a system and a recording was perfect, not everyone would like what they hear.

I have made changes in my system, over the years, that were clear, definite improvements in the technical behaviour of the circuit.

When listening for the first time (or even the second time) I didn't recognize it as an improvement.

Given time it became clear that that piano DID sound more like a real piano.

That Martin acoustic guitar did sound more like a Martin acoustic guitar.

Being a recording engineer, I know what these instrument sound like in the real acoustic world.

The thing is, I had become accustomed to the flawed sound of the previous circuit.

This is something that we all need to guard against constantly.

Get to know the sound of real acoustic instrument (without mics or amps or loudspeakers). They are the only real point of reference we have.

Whenever I hear someone say a system sounds "good" I take that with a large grain of salt.

There are plenty of people that think 1970's Japanese receivers and Bose speaker sound "good".

I just had one at my house not 2 hours ago. He was impressed with my system but he should have been blown away. The bottom line....he doesn't have a clue.

Tre'


Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: What this is all about, posted on June 26, 2012 at 17:50:20
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 These stupid, repetitive threads have nothing to do with logic and reasoning: instead they are all about Dennis' massive ego which requires constant massaging by his minions. He assumes a God like persona with superior knowledge to mere mortal scientists, posting bellicose and incoherent sermons on the mount which are viewed as the one and only truth by his sycophantic followers. It’s their idolatry he craves. He loves nothing more than constantly rallying his troops against Tre and other unenlightened unbelievers who dare to challenge his rabid evangelising. That’s why when one thread dies he has to post more pompous claims to get the whole process going again.

That’s what all this crap is about. One man’s insatiable ego.

 

RE: Hey Dan!, posted on June 26, 2012 at 18:10:41
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 Dan,

No need to build it to hear it, because I am sure - you will not do it right.

Why don't you come to RMAF this October, and hear it at its best - over a few days? Much easier, much cheaper.

You won't ever say (or think) a thing about Miller or filtering, non-issues, when you hear it properly, .... like on the last day of the show.

Cheers,

Jeff Medwin

 

RE: Hey Tre!, posted on June 26, 2012 at 18:15:54
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002






A friend of mine built this with the help of Dennis, etc. The component values were all given to him.

I ask Dennis over the phone what the differences were between this circuit and his and he wouldn't really say. He did say that he uses multiple small by pass caps on the cathodes. My friend used only one but he used the right brand and the right size main cathode bypass caps.

Dennis complained that the current was a tiny bit to high in both the driver tube and the output tube and that the voltages were a tiny bit (and I mean a tiny bit) too.....I can't remember, I did take notes, I will have to see if I still have them.....well, high or low.

What he did say lead me to believe that it was very (my word) close.

When push came to shove Dennis said that 1" of the wrong wire will ruin the whole amplifier???!!!

I had it here for a few days. I circuit traced it and drew these schematics myself.

It's sounded awful.

On the test bench the PS was unstable even when not playing and the HF rolled off starting at 11kHz. Dennis has said (here on the AA) that his amp starts to roll off at 15kHz. He said the tubes he uses have less Miller capacitance than NOS. Dennis said (here on the AA) that his amps will start to roll off at 11kHz with Sylvania NOS 2a3's and 9kHz with RCA.

Tre'


Have Fun and Enjoy the Music
"Still Working the Problem"

 

Pull the wad out of your panties..! nt, posted on June 26, 2012 at 18:45:24
drummerwill
Audiophile

Posts: 525
Location: St Louis Mo.
Joined: January 7, 2003

 

RE: Sheer class, posted on June 26, 2012 at 18:53:42
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 Your eloquence astounds me. It's funny how some people react when faced with the bitter truth.....

 

Bitter truth...., posted on June 26, 2012 at 19:08:53
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 The bitter truth is, that you are one clueless individual mach1, and on this Forum, you always have been clueless.

I was not going to post on this comment you made, I was just going to let it stand out as an example to knowledgeable others, of you being WILDLY-out-of-touch with reality.

The real truth is, a Serious Stereo 2A3 amp exists since 1989, which disproves ALL that you and your cronies say and think and so stupidly profess up here.

You have a right to say what you like, within reason. Go ahead, show me what else you got !!

Jeff Medwin

 

Thanks Tre!, posted on June 26, 2012 at 19:49:20
DanK tubes
Audiophile

Posts: 372
Location: California
Joined: November 9, 2004
 Saved me some trouble.
Dan

 

RE: Bitter truth...., posted on June 26, 2012 at 19:56:25
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 'The real truth is, a Serious Stereo 2A3 amp exists since 1989, which disproves ALL you and your cronies say and think and so stupidly profess up here.'

Sorry Jeff I don't quite get the connection (or the grammar). But then again, these threads have never been about logic and reason, just a giant ego bigger than Texas.

 

RE: The road ahead ....is a cliff with a trail of lemmings following you , posted on June 26, 2012 at 20:15:23
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 'This is about as nonsensical a post as I have ever observed on this board.'

I thought his previous mind implosion which prompted your 'kool-aid' response was probably a bit more nonsensical. Pity it was deleted: it gave great insight into his thinking, and could have deterred many lemmings from following over the cliff. Some people in my office refused to believe it was authentic; others found it highly entertaining.

 

8 have been sold since 1989., posted on June 26, 2012 at 20:15:52
GEO
Audiophile

Posts: 2699
Joined: April 7, 2000
 Move on.

 

It only takes one amp...., posted on June 26, 2012 at 21:02:06
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 To totally disprove the BS what you and your cronies put forth up here.

Guess what, that one amp exists, the best 2A3 amp ever produced, and it disproves any baloney you try to post on this Forum.


Jeff Medwin

 

RE: Remember this thread, posted on June 26, 2012 at 23:08:12
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 The bitter truth is, that you are one clueless individual mach1, and on this Forum, you always have been clueless.'

Jeff, remember this thread ?

http://db.audioasylum.com/mhtml/m.html?forum=tubediy&n=132941&highlight=cathode+bypass+mach1&search_url=%2Fcgi%2Fsearch.mpl%3Fauthor%3Dcastlesteve%26forum%3DALL%26sortRank%3DNone%26sort%3Ddate%26sortOrder%3DDESC

Where the 'clueless' people had to teach you how to correctly calculate the -3db cutoff point of a cathode bypasss capacitor.

 

Sure do...., posted on June 27, 2012 at 00:36:25
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 And you still don't get it.

I didn't read it, I DIDN'T READ IT THEN - OR NOW. When it comes to EE and Rk bypass formulas, I do not use those formulas. No loss at all.

I determine the amount of uF, (and the film cap bypass values which you are unaware of) by ear, bracketing uF values. Can't ever get an equal (or better) SONIC RESULT to "my" approach.... with ANY textbook Formula and pushing a slide rule.

That is an important point, you do NOT have to be an EE to come up with truly outstanding sounding audio amps.

MOST EEs stick to the formulas in RDH-4, and it stifles advancement in musical performance. They are unwilling to try unorthodox circuit approaches, like I am. Imagine a L non critical L1, why that must be heresy, but we have sure found out ...it isn't.

Cheers.

Jeff Medwin

 

pissin match , posted on June 27, 2012 at 06:13:52
Kloss
Manufacturer

Posts: 849
Location: WI
Joined: January 25, 2012
 Who care who knows more. And since some feel more knowledgeable why not school those with less experience instead of insult there lack of it? These type of threads really bring down this forum.

 

RE: at RMAF, posted on June 27, 2012 at 07:20:55
RPMac
Audiophile

Posts: 231
Location: So. Mississippi
Joined: January 3, 2005
 I've been here much longer than 2 years.

What do you believe the effect would be if you and a few others would follow your advice and "move on"????

I believe these type threads wouldn't exist and the forum would be much more hospitable to us "lemmings" looking for advise!!!

 

RE: pissin match , posted on June 27, 2012 at 11:42:10
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
 Hello there! I don't have your first name, but your post deserves an answer.

I certainly don't care who knows what. Neither do I care who gets credit for a good idea.

Good ideas are often unconventional and are sometimes rejected out-of-hand by those who think they have all the answers, and think that people like myself should be sidelined so that only the dominator's ideas can be aired without insult and personal attack..

We haven't met each others-- in most cases, so any personal attacks are at once dishonest and irrelevant.

Most forums on the internet are like this one-- since it has only a one-way communication, and since the fellows can't be present with each other-- this form of communication is extremely barbaric and at its very best, can only be marginally useful.

Certainly, loads of information in the form of numbers, charts and graphs can be transmitted efficiently. ("and knowledge shall abound, but the way of truth they know not")-- it goes something like that.

That's the trap we're all caught up in-- when we depend on the Internet-- we can efficiently transmit information which anybody can get anytime out of readily available texts-- it isn't hard to obtain-- but when someone has a better way of thinking or of approaching problems in general, or has a better idea-- maybe even knows how and why it works-- he gets subjected to ridicule because he does not generate reams of data.

These kinds of forums utterly fail because they tend to become dominated by information freaks, mathematicians, and data-hoggers who WANT SCHEMATICS to pick apart-- they DO NOT want ORIGINAL THINKING-- especially in our cases.

They're just being LAZY!

No one is trying to insult anybody else.

We ARE schooling the non-gangsters who are ALSO reading these forums-- and who don't have the time to try to outwit the gangsters who try to dictate how this forum is being used.

Internet Bullying is what this form of gangsterism is normally called, and Americans have had just about enough of it.

The people who are benefitting from these honest, on-line discussions about how to think through an audio problem, and how to bring a new design to perfection BEFORE it is built or breadboarded have asked me to keep contributing to this forum even though my time is limited, and I deal in CONCEPTS-- NOT-- I repeat-- NOT how-to-assemble blueprints or kit-form formulas, snatched out of RDH or on-line calculators.

Myself and a few others teach HOW TO THINK--- NOT how to gather information.

INFORMATION IS CHEAP.

KNOW HOW is priceless, and is a product of rightly-applied thinking, imagination, and a willingness to explore the unknown.

IT IS NOT a product of formulas, books, and etc. We all use those. We all refer to those when we need them. I do. SO WHAT?

This is not a war between science and imagination-- BUT SOME WANT IT TO BE. We USE BOTH every day.

Certain forum members wish to force people who use these forums into an INFORMATION ONLY context. That is STUPID.

Original thinking kinds of threads are bringing down the forum?

Exactly the opposite is occurring-- the good-hearted, the honest, and those who can imagine into the future are reading these posts every day.... and are building-- unknown to most of us who post (I thank you for your efforts no matter who you are-- I know it takes time to do it!)-- equipment that is superior to anything that is being posited by the information-only people.

So are we bringing this forum down? No, we are allowing it to breathe free-- maybe FOR THE FIRST TIME ever? We are encouraging those who can think into the future-- beyond mere numbers and published materials-- to go ahead and think out-of-the-box. To LEARN HOW to think originally, to create new and more useful ideas, and to learn how to design applications for themselves.

This is, and has been occurring because of the posts I have made on TUBEDIY over the years, and because others have done the same thing-- have not given up on the people who don't post-- but READ these posts and benefit-- and have pulled far ahead of the few gangsters who wish to dominate this forum.

Those people who don't post often-- but are reading this-- they are the ones that count-- and should count to the kind folks that sponsor this site.

The sponsors benefit more than any of us when people are learning how to think for themselves, and to question authority-dominator figures, and to go on, invent for themselves and build better.

When that happens, products are bought and sold. The sponsors will sell some of it to all of us, including myself.

Your forum is not being brought "down". It is finally growing up.

---Dennis---

 

RE: What this is all about, posted on June 27, 2012 at 11:45:19
lakerfan
Audiophile

Posts: 354
Joined: April 9, 2002
 His amp is real nice ok . But......... I have this guy who lives on our block. He would always push my buttons during our town hall meetings with some opinion concerning the community. All the older people would bite and get all worked up. This went on for a couple of years. Then folks stopped arguing with him. " They removed the button ". When he no longer had a" button to push", he stopped coming to the town hall meetings. Today when I see him , the talk revolves around simplier things like the hot single moms croping up, or how much we enjoy the loosing ways of the Chcago Cubs, our wonderful home town team on the Northside. Guys.... "remove the button" ! And without reacting to other posts, simply speak your truth about what you have learned through your work with amplifiers. I wonder then, how much would be posted that you find outrageous. It takes MORE THAN ONE to argue.

 

RE: What this is all about...reality check, posted on June 27, 2012 at 12:28:32
deathtube 667
Audiophile

Posts: 540
Joined: November 25, 2010
 Dennis Fraker posts a great deal of advanced conceptual information regarding the design of modern SE tube amplifiers.

The goal is to inspire the building of great SE tube amplifiers and nothing more.

There is no cult followers, lemmings or whatever negative designation critics wish to assign modern SE tube amp builders.

What I do see is a group of individuals who are compelled to appear on every Fraker thread and spew mindless venom.

It serves no purpose since these negative individuals have never built and have no interest in learning how to construct modern SE tube amplifier circuits.

dt 667

 

RE: It only takes one amp...., posted on June 27, 2012 at 19:03:52
Donald North
Manufacturer

Posts: 1109
Joined: February 8, 2001
 Unless that one amp is made with pure silver transformers, then it has no chance to be the best 2A3 amp ever produced.

Donald North

 

RE: It only takes one amp...., posted on June 27, 2012 at 19:15:30
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
There's certainly nothing wrong with silver-windings in a transformer, but (ask Mikey at Magnequest) there's SO much more to good transformer design.

One thing I might mention here is that the same conductor INSIDE the transformer's windings behaves differently than the same wire OUTSIDE the transformer (lead-outs).

A word to the wise.

---Dennis---

 

RE: Hey Tre!, posted on June 27, 2012 at 20:01:41
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
 Got quite a few mistakes in there, Guy.

No wonder you don't think it works-- I don't think THIS schematic does, either!

I hope nobody built this thing-- what you have here is a clock-radio amp.

There are wrong parts values and entire sections are left out... or the proper connections into circuits are in the wrong places.

Voltages are also off.

Hey! I don't mean to be mean here-- part of my technology is proprietary-- it isn't a freebie, so if you don't have it, it's not your fault.

The operating principles that I have shared and the concepts are what's really valuable anyway.

Good builders will get most of it right without me, although they won't get the entire result, it will be good.

I would refer people to Sound Practices articles on Loftin-White amps. If one studies those enough, he will invent ways to get the desired bandwidth for music.

---Dennis---

 

RE: Sure do...., posted on June 27, 2012 at 20:56:34
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 Jeff the point is you posted

'You do not want the -3 dB point on the Rk of the driver and final stages to be the same frequency, or to "stack" on each other. If you use a 10 uF WE cap ( I'd prefer the 6.8 uF GE film with bypass over the WE513C-dealer's choice) you are at 3.97 HZ. The values I suggested for the SRPP's 270 ohm bypass, 60 uF to 75 uF will pretty much guarantee they do not stack at the same frequency.'

At the bottom is a handy calculator I often use, 'hope you and other Members enjoy it.

This is just plain wrong wrong wrong: the -3db point is NOT 3.97Hz. You present yourself as some sort of design guru, so some innocent newbies are going to believe this garbage. This is my issue. When you do things like this you spread disinformation.

'When it comes to EE and Rk bypass formulas, I do not use those formulas. No loss at all.'

No you just tell all and sundry to use the wrong ones.
The calculator you linked has not and never will spit out the correct -3db points. What intrigues me is why you would use it in the first place, since you design 'by ear'. As I stated before, these threads are not about logic and reasoning they are about egos. And you still don't get it.

 

RE: pissin match , posted on June 27, 2012 at 21:10:46
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 Great rant Dennis, up to your usual standard. I love the way you alternate between bellicose Dennis and poor little victim Dennis.

Ideas, concepts; great when they are presented as such. The problem starts when people start presenting their ideas and concepts as factually based truths.

 

Sound Practices Information....., posted on June 27, 2012 at 21:14:01
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 Sound Practices, Issue #5, Spring 1994, Page 3, "A Direct Coupled Single Triode Amplifier" by Ciro Marzio and Cristiano Jelasi".

Very nice article.

I'd suggest a modern power supply.

Jeff Medwin

 

RE: It only takes one amp...., posted on June 27, 2012 at 21:31:02
mach1
Audiophile

Posts: 359
Location: Brisvegas
Joined: April 24, 2005
 'Guess what, that one amp exists, the best 2A3 amp ever produced, and it disproves any baloney you try to post on this Forum.'

Jeff, you could not possibly have heard all the 2A3 amps in the world, so how can you make that statement?. Your brain is a logic fee zone. What you just posted was a used car sales pitch at best. Does Dennis pay you a commission?

 

RE: pissin match , posted on June 28, 2012 at 00:20:25
tube wrangler
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Posts: 1363
Location: USA
Joined: January 29, 2007
I wish you the very best-- always. Facts are all around us every day.

You and I are living facts. That lawn that is growing outside your door-- that is a fact.

My grounds are watered by gravity-feed-- high pressure from a creek. It delivers 85 P.S.I. at about 5 G.P.M. I'd say that is a fact.

That you become what you eat is also a fact. That any kind of drug-- ANY kind-- will destroy one's normal instincts concerning facts-- that is a fact.

That some people cannot tolerate honest competition and tend to react to it negatively-- make personal attacks instead of analyzing what's going on around them and adjusting to it-- well, that is a fact that man has to live with. It is also a fact that such behavior is extremely counterproductive.

It is a fact that world wars are fought because some people can't stand competition.

And-- it is a fact that millions of people die needlessly every time they do it.

But some still do it anyway.

And that is a fact.

---Dennis---

 

RE: Hey Tre!, posted on June 28, 2012 at 10:13:21
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 "There are wrong parts values and entire sections are left out. Voltages are also off."

So....If it's wrong tell us where and how.

This is what you and your friend told my friend to build. If it's wrong it's not the builders fault. He just built what he was told to build.

Entire sections? What do you mean by that?

You amps is a two stage DC 2a3 amp? Correct?

What sections are missing?

"No wonder you don't think it works-- I don't think THIS schematic does, either!"

So tell us what is wrong with it.

Put up or shut up!

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

here's what started it, posted on June 28, 2012 at 10:48:57
GSH
Audiophile

Posts: 184
Location: S. Cal
Joined: January 19, 2011
 Here's my original post, and yes I was coached by both J and D as the project was made. And yes, there's what I'll call micro differences, some of which "may" have been improvements....

http://db.audioasylum.com/mhtml/m.html?forum=tubediy&n=153234&highlight=Satan+patiently&search_url=%2Fcgi%2Fsearch.mpl%3Fforum%3Dtubediy%26searchtext%3DSatan%2Bpatiently

I had not "yet" tried multiple by-pass caps, because I didn't have any at the time. I did however make an effort to minimize wire, see the pictures (much less than what Dennis does, I've seen the underside of his amp BTW).
I also had a much lower DCR power trans than Dennis uses, whatever that's worth, and I used dual 5R4GY's instead of one 5U4GB, which Jeff should like. I had custom made filament transformers with a tab for a CT that the R and Ck directly soldered to, from there to ground, (no wire).
Yes the voltage on the 2A3 was a little bit higher than what was "recommended", I didn't think that could "ruin" anything as the 2A3 was still operating UNDER max dissipation. I tore the amps apart 2 years ago or more. Before I did, I changed the driver to a CCS loaded lo mu triode,
instantly cleaner, better. I also changed the PS to "normal" which made other noise go away, but we now know that the original PS was "no good".



Jeff later felt happy to thrash my build, yet thankfully admits having misadvised.

See:

http://db.audioasylum.com/mhtml/m.html?forum=set&n=69636&highlight=grant+handley&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fforum%3Dset%26searchtext%3Dgrant%2Bhandley

 

RE: here's what started it, posted on June 28, 2012 at 11:44:27
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 Hello GSH,

You relied primarily upon me, and I was NOT correct in values and voltages in several areas, as my understanding of the circuit was not as good back then, as it would be today.

We both should disclose the fact that I told you to make the AC cord (ONLY) out of inexpensive Carol 300 VDC or 600 VDC 12 AWG wiring, and the audio out of TCSS and silver wire.

The TCSS never got installed. You wired the amp mostly with the inexpensive 12 AWG Carol, which has a "big wire" (very negative) thick and out-of-time sound to it.

Use of huge Carol 12 AWG hook up wire, in places other than the AC cord, guaranteed poor sound IMHO.

I also had the B+ supply filtering and shunt regulators mis-done, totally my fault back then, as far as obtaining low ripple. I made the same error with Slownlo, and even my own implementations in 2008-09.

You also never sent me a finished schematic of what you made, so that I could comment on voltages, and various obvious errors I would have spotted. IMHO, we BOTH made errors back then.

That a CCS improved things is not surprising at all to me, it was a band aid for numerous implementation and circuit errors. You gave up on the project, before fully informing me of exactly what you built and allowing me to suggest corrections. About two years later, in 2010, I told you quite precisely in what three areas that amp was "boogered", and it certainly was.

Its a shame you have never heard one of Dennis 2A3 amps, to know what performance level is possible. I have, that is what keeps me active.

Live and learn.

Cheers,

Jeff Medwin

 

RE: What this is all about...reality check, posted on June 28, 2012 at 12:18:37
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 "It serves no purpose since these negative individuals have never built and have no interest in learning how to construct modern SE tube amplifier circuits."

That's BS. You have no idea what I (and others) have built.

"Dennis Fraker posts a great deal of advanced conceptual information regarding the design of modern SE tube amplifiers.

The goal is to inspire the building of great SE tube amplifiers and nothing more."

More BS. Dennis' goal is to sell amplifiers and his concepts are not advanced in any way.



Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

"the proper connections into circuits are in the wrong places", posted on June 28, 2012 at 12:45:58
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 What do you mean by that?


Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: here's what started it, posted on June 28, 2012 at 12:55:07
GSH
Audiophile

Posts: 184
Location: S. Cal
Joined: January 19, 2011
 "The TCSS never got installed. You wired the amp mostly with the inexpensive 12 AWG Carol, which has a "big wire" (very negative) thick and out-of-time sound to it."

Yes, true BUT: the Carol 12g wire was only to the rectifier (yellow and red), and the ground (less than 6" total in one uncut piece from the HV CT
to the input, through the cap terminals. There's no other wire in the circuit, period, except for the lead to the OPT which was paralleled with silver wire. BTW we both know Dennis uses the stock red and yellow leads out of the stock Hammond power transformer to his 5U4GB. That sure isn't TCSS. So, the ONLY real wire "flaw" is the 6" ground, that actually only counts from C2 to the input, which is less than 3".

So the 3" ground wire of heavy copper, was "bad". OK

The difference in the op points is NOT large, as stated, still UNDER max dissipation for the 2A3, and the 7B4 was "close". I don't see how this could dramatically change anything. I don't think the small voltage differences could be "heard", in fact, they could easily blur between "perfect" and what you would call "way off" just with the line voltage changing. So I veto that.

The missing multiple by-pass caps is the largest "flaw" and I admitted that from the word go (see original post)

I also got tired of the hum and installed a Bourns pot, which fixed that.

I'm not really trying to defend or prove anything, just state the what is.
I do believe that the paralleled caps (if done whatever right is) could be an area of improvement for ANY CIRCUIT, which is why I brought it up in my other recent post. I give Dennis direct credit for having pursued this, although I don't have any direct experience with "what exactly" he has done, other than note that he said "it's expensive, and will cost more than the sum of the rest of the parts". With that, it's hard to get moving, expensively, into darkness, to maybe achieve light.

Furthermore, I think a direct coupled SE amp is a good sounding thing.
Perfecting it, is just an interesting set of possibilities.
I and many others may not prefer the 7B4-2A3 to what I or those others are preferring now, but overall improvements in PS, wire and caps are still valid for other circuits, so whatever real findings Dennis can show,
can likely "help" other designs in these areas. I wish this "tone" could be upheld in this discussion.

 

RE: Hey Tre!, posted on June 28, 2012 at 14:20:10
tube wrangler
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Posts: 1363
Location: USA
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Correction! I don't tell anyone to build anything-- or completely how to build it.

Others do, and their contributions sometimes help, sometimes don't.

I, for one, admire them and appreciate their efforts. Remember, that these guys are working for nothing-- on other people's behalf. Now, that's pretty decent in my book, even if a few honest mistakes are made. (They will be-- SO WHAT? It's free- just use the GOOD parts of it, for God's Sake!).

That's life! Full of advice-- and only a few things actually work. Then, the real problem is-- as always-- how to APPLY some of that advice-- and maybe what to leave out also!

Again, that's life! Get used to it-- I happen to enjoy it and like to live on Planet Earth-- with all its faults!

As you should expect, I don't give out schematics or tell people exactly how they should build their own projects, since I'm part proprietary, and part understanding-- of the fact that every guy has the right to build anything any way he wants anyhow!

All we're doing-- at least that's me-- is allowing a peek into the THINKING PROCESS that can lead to excellence. You DO NOT get schematics, pre-designed kits, or any advice on how to build things-- except as general accurate, honest thinking processes that can-- if properly understood, lead to sheer excellence.

That's what you get for free from me. Nothing else. Be happy that it's available! Learn from it! Or-- don't. It's your call.

Developing an antagonistic attitude over it is childish.

---Dennis---

 

RE: Sound Practices Information....., posted on June 28, 2012 at 14:40:46
tube wrangler
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Posts: 1363
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 Well, guys, what are you waiting for? Good Ole' Jeff has given you the goodies!

Now, you can read the articles and learn WHY these Italians liked this approach better than anything else. Remember, they were listening to Italian Opera-- which is demanding musically.

Sure, I have perfected it. But, you cannot deny that their version of the concept did sound very realistic-- musically, even though it was operating in a narrow bandwidth-- measurement-wise..

Of course, that didn't really hurt it much.

Why is that? Even after rolloff of both highs and lows, the thing still responded well to micro-signal input. What happened is that although highs were rolled-off, THEY WERE STILL THERE!

That is FAR better than an amp that is measured flat-- say-- out to 35,000 HZ, but WILL NOT RESPOND to micro signals in frequency ranges even well below that, but must be POWER-DRIVEN to give even a passing nod to those energies.

Of course, the Miller-Effect eliminated amp will not drive a H.-EFF. speaker well at all, even though it measures well AT FULL POWER..

What happens here is that the rolled-off Italian design reproduces FAR more highs than the amp that has much more H.F. extension-- but not into a H.-EFF. speaker-- the extension to 35,000 HZ (as an example) is only on paper-- it is real enough if the amp is driven hard, but it DOES NOT occur in a H.-EFF. SPEAKER when the amp IS NOT driven hard..

In this case, amp measurements on paper don't prove power-response to SMALL signal input. The Italian's amp does respond-- at small signal levels, and that is the secret of it.

It can be rolled-off at both ends of the audio frequency extremes and yet deliver FAR more input of those rolled-off frequencies into an actual speaker-- than can the Miller Effect-Eliminated amp that measures perfectly, but will not respond to micro-signal input..

Now, I'm NOT interested in another mud-slinging contest over this. This is FREE, valuable information, TRE, MACH1, and GEO.

TAKE it or LEAVE it.

The Italians liked it and had fun with it. And, that wasn't even close to what is possible.

Oh, I KNOW-- several of you don't think that these are serious amplifiers. What did they use in the front-end-- a 12AX7?

Oh, but that can't work! It's that horrible Miller stuff! Yeah, sure. But it DOES work.

Have you ever asked WHY? I did.

---Dennis---

 

RE: Sound Practices Information....., posted on June 28, 2012 at 15:02:16
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 "What happens here is that the rolled-off Italian design reproduces FAR more highs than the amp that has much more H.F. extension-- but only on paper."

BS


"TAKE it or LEAVE IT."

I'll leave it and argue that it is a flawed design.

"Oh, but that can't work! It's that horrible Miller stuff! Yeah, sure. But it DOES work.

Have you ever asked WHY?"

It doesn't work so I have no reason to ask why it works.

You still haven't answered my question.

What do you mean when you say, referring to the schematic I posted, "the proper connections into circuits are in the wrong places"?

The plate of the 7b4 is connected to the last cap in the PS filter with a plate resistor. Just like in your amplifier.

The cathode of the 7b4 is connected to ground through a bypassed cathode resistor. Just like in your amp.

The grid of the 7b4 is connected to ground through a grid resistor. Just like in your amplifier.

The plate of the driver is directly connected to the grid of the output tube. Just like in your amp.

The plate of the output tube is connected directly to the output transformer. Just like in your amp.

The output transformer is feed from the second C of the PS filter. Just like in your amplifier.

The cathode of output tube is connected to ground through a bypassed cathode resistor using the CT of the filament transformer. Just like in your amplifier.

So tell us Dennis, what connections are in the wrong places?

You say some awful silly stuff some times.

Tre'


Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Sound Practices Information....., posted on June 28, 2012 at 16:13:56
GSH
Audiophile

Posts: 184
Location: S. Cal
Joined: January 19, 2011
 "What happens here is that the rolled-off Italian design reproduces FAR more highs than the amp that has much more H.F. extension-- but not into a H.-EFF. speaker-- the extension to 35,000 HZ (as an example) is only on paper-- it is real enough if the amp is driven hard, but it DOES NOT occur in a H.-EFF. SPEAKER when the amp IS NOT driven hard.."

So, if it IS "driven hard" then are we back to equal (other than gain) ?

The main reason I left the hi mu driver, was I didn't need the gain, in fact a mu of 18 is still more than I need. This means that I'm using more than half of my available 2V of signal from the source, whether a CD player or a phono-pre, and, of course, ATTENUATING LESS. Is this "driven hard" ?

In addition, regardless of Rp or Miller issues, selected lo mu drivers can be measurably if not also audibly, lower distortion, because they are more linear, period. This is usually a good reason to use such an item, right?

I always thought hi mu triodes were for situations where hi-gain was needed, accepting the fact that there's a distortion "penalty" for such an "advantage". I think this is basically still true?

The real question is whether or not hi mu equates to higher low level sensitivity. "technically" is doesn't...

I'll admit, that once I made a direct coupled SE parafeed amp with a CCS loading a lo mu driver, I hadn't heard anything better, and was also amazed by the low level retrieval. The amp also had 2 less caps in the signal path...You may want to try it Dennis, use your front end if you prefer.

 

RE: Sound Practices Information....., posted on June 28, 2012 at 19:37:58
tube wrangler
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Posts: 1363
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Joined: January 29, 2007
 Very intelligent and good questions-- all of them.

Let's see if I can shed some light on them, not all of this may apply to your own situation, so don't consider it the only things you can do.

My approach to anything is how can I get it perfect... that may require changing more than the unit in question-- it may require designing a whole system to get everything as perfect as I can make it. So, again, this may not be gospel for your circumstances-- I'll do it for your discussion:

(1) I'm not sure that paragraph makes as much sense as it can-- let's take another look at it-- let's try and improve on my wording:

What I mean is that the Italian design- with its low-plate current driver stage responds better to small-signal inputs than an amp that has a higher plate-current driver installed for the purpose to overdrive Miller-Effect on the output tube grid.

The low-plate current driver is easier to drive with input signals entering the amp than the higher plate current driver is.

This is an advantage where the amp is not pushed to full output-- as in the case of High Efficiency speaker..

Should one wish to push the output tube to full output, then the higher plate current driver will get much more input from the source components, and we will enter the area where it can perform better. It will also have a wider bandwidth because it is now overdriving the Miller Effect on the output tube grid.

We run into a severe fidelity problem when we DO NOT push this high plate current driver amp to full output. In that case, the hefty input tube plate current acts as an incoming signal blocking device, rendering the amp hugely less transparent and dynamic. As you probably already know, amps have to be power-sized to their speakers.

A much more honest appraisal would be-- the amp DRIVER STAGE must be sized to the SPEAKER.

-----This is far more important than matching the output stage to the speaker-----!

The thing that I notice most when using tube amps is that the power from the amp with the low-plate current driver, while delivering less total watts available from that amp-- puts out audio power that is infinitely more powerful and potent-- and has far greater ability to drive the speaker AS LONG AS that speaker doesn't need more power yet.

If the speaker does, you have to have a larger driver stage. In such a case, you give up a LOT of fidelity-- you would be much better off to change the speaker out and opt for more efficiency.

(2) If the amp is driven hard with the high-current driver stage, more input is being put onto its grid. This overcomes some of the limitations that the high-current driver exhibits under lower drive conditions. Is this performance as good or as potent as running the low-current driver stage into a speaker that is efficient enough to place that driver stage into its correct operating range?

NO! NOTHING will outperform the amp with the High-Mu, low-current driver stage-- IF the speaker loads the amp properly-- and never overloads the amp.

(3) "I didn't need the gain". The above discussion is for a 2-stage amp, so the high-gain input stage is needed. The overall gain of such an amp-- using a 2A3 output tube-- is in the range of 19-20 db. This is discussed in Jim Smith's book "get better sound". In there, you can read what Jim considers ideal gain for an amp. That is the range we have here..

Typically, with this kind of amp, we'll use a CD player, computer Sound Card, or a Phono stage that outputs-- ideally-- 3.2 to 3.6 volts Single Ended. In such a case, no preamp stages are needed, the 2-stage amplifier is directly driven by the source component. Volume control is accomplished by a Ladder Attenuator, or an L-Pad Attenuator.

Series and transformer or autoformer type attenuators are not used because series types cannot maintain an ideal load on the source regardless of volume setting.

Transformer or Autoformer types are OK for good midrange and voice performance, but fall short of maximum transparency-- compared to what we can get by eliminating them. Another thing that MUST be eliminated, in any really good system is all active preamp stages except for the Phono stage-- which is, unfortunately, necessary.

(4) Don't let linearity charts or other data fool you into thinking that they always apply to all situations under all musically-driven conditions. These can certainly mislead, although you will often catch me looking at them, and trying to find the more linear areas-- IF everything else is ALSO OK. IF NOT, then a workable balance must be thought-out across the entire amp's operating range and conditions.

Remember this: all devices, be they tubes, solid-state devices, caps, resistors, transformers and inductors-- have ranges where they operate well and ARE NOT being stressed-- thermally, signal-input, or power dissipation-wise. When parts are not ever stressed, they are far more dynamic and transparent, and MUCH more musical. With some tubes, this WILL NOT be the most "linear" portion of the tube curve. SO WHAT?

Basically, getting too hyped-up over theoretical "linearity" or "low distortion" can cause one to make overall engineering mistakes in amp design that will rob one of the musically linear, distortion-free presentation that you really want----- IN THE SPEAKER.

(5) High-Mu triodes are used where they can eliminate an extra gain stage. An extra gain stage-- regardless of intent-- is always a sonic disaster if it can be avoided. The more parts and gain stages you have, the slower your amp is, and the less transparent it is.

Anytime you can eliminate a coupling cap-- do it! NO cap exists that can be accurately put in series with an audio signal.

---Dennis---

 

RE: Hey Tre!, posted on June 28, 2012 at 21:00:51
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 The only antagonism I have for you is because of the misinformation you spew to the detriment of the neophyte.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Sound Practices Information....., posted on June 28, 2012 at 21:08:43
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007
I neglected to mention something very important in this kind of amp-- it's critical.

When you're running a High-Mu, low current device as a driver-- that item must have unlimited plate power available, and it must have very tight voltage regulation.

If you attach a constant-current device-- either to the plate or the cathode of the driver stage, the performance should degrade because of the added phase problems initiated by the Band-Aid thus applied.

If, instead, the sound improves, and the amp has more power with the C/C applied, then that is proof of a power supply problem on the driver's plate supply.

The supply should have very tight voltage regulation-- you can't do this with any regulating device-- it will fail to closely enough follow music's changes. Instead, you use resistors for shunt-regulation. Ideally, you can run up to 40 ma., to ground, and use only 8 tenths of a milliamp of that for the driver plate current-- maybe slightly more-- one milliamp with a single section of 12AX7A-- which is recommended because so many excellent varieties are available today.

Sorry I neglected to mention this. If you've had problems, look here.

---Dennis---

 

RE: great advice, Dennis..., posted on June 29, 2012 at 05:36:54
deathtube 667
Audiophile

Posts: 540
Joined: November 25, 2010
 The overall concept of "modern" SE tube amplifiers is what is important, not the rote copying of a schematic.

I took a lot of information from Jeff Medwin aka Drlowmu and but I did not copy what he did exactly.

I adapted the overall "modern" approach to my circuit and came up with something useful and good sounding to my ears.

The detractors are not willing to buy the recommended parts, build a circuit or learn anything.

They want to publish poorly executed/incorrect Serious Stereo schematics and say that "modern" SE tube amps don't sound good.

The negative people just want to police the AA tube forums and try to bully other builders into silence.



dt 667

 

RE: great advice, Dennis..., posted on June 29, 2012 at 08:52:03
tube wrangler
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Posts: 1363
Location: USA
Joined: January 29, 2007
 Don't you-- or others-- worry about it. They don't have anything that could work-- the mistakes are just too numerous to bother mentioning.

Their thing can't, and won't perform as they have it drawn up/perverted.

Now you know why I don't give out schematics-- I don't want them butchered.

---Dennis---



 

cobalt, posted on July 1, 2012 at 07:00:39
Kloss
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Posts: 849
Location: WI
Joined: January 25, 2012
 nt

 

curious..., posted on July 2, 2012 at 10:25:18
Ralph
Manufacturer

Posts: 2188
Location: Minnesota
Joined: April 24, 2002
 Hi Dennis,

I don't think I am in competition with you directly; I am wondering if you saw my posts below? I particularly interested in the comments you made about voice coil heat and also how you measured that. You can respond to this post if you like.

 

RE: curious..., posted on July 2, 2012 at 19:36:50
tube wrangler
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Posts: 1363
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 Ralph, I understand.

Trouble is, if you think we've got problems with MISUNDERSTANDERS INC. now, just let me get started on VC heat! We could take years on such a thread!

AND VC (voice coil)-- what did I call it-- fibrillation? Yes. That's when the amp is tossing things at the speaker that are NOT MUSIC-- things that are out of time-frame, and cause the speaker diaphragm/VC to both overheat and to deliver a lot of motion that isn't related to the music at hand-- the diaphragm/VC is in fibrillation-- just like a Heart Patient-- it's got useless motions.

OK-- so the VC gets hotter! You would too if you were putting out tons of energy and weren't getting a lot done (not anything very much, that's for sure-- there's always SOME wanted motion there-- otherwise we'd have no music at all, so this is a discussion of DEGREE)!

To me, it's obvious, we can certainly hear the results of it, and we are certainly seeing huge differences in the actual driving abilities of different amplifiers-- even when delivering the same watt power into a speaker.

Well, that's just empirical/observation/opinion! True. So prove it! OK-- you can do it yourself-- just measure the heat buildup in the VC. You can also look at a woofer cone and see whether it is moving all around, or whether it is steady-- yet is producing high SPL output. Yes-if it's motion is virtually undetectable, but things are loud- that's a better amp!

Today, engine builders use heat-sensing guns all the time. Just point the thing at what you want a temp reading on. What turns you on? Water temp, combustion flame temp, exhaust temp-- piston-top temp while the engine is running? Sure. Done. A good one of these can read piston-top temp right thru the head or cylinder block.

Nice. OK-- no surprise to me-- I'm the guy who was using Hard Rock Mining Mud Pumps in the Oil Field. No, it wasn't popular with the Oil-Field-Only guys.

TOO BAD-- just another problem NOT SOLVED by those who can't imagine something different so things will work better. They, instead, wanted proof. (Always). By the time they get that, 40 other things will have gone wrong on their watch-- and have to be fixed because they wanted proofs all the time-- while problems they refused to solve mounted up-- it's nothing new, Mankind always does this! Look at WW1, WW2, and NOW FOLKS-- stay tuned!!! WW3!! Tah-Dah!

SAME old BS. Problems DID NOT get solved BECAUSE all people do about anything is keep demanding proofs from other people instead of doing right thinking and action-- THEMSELVES. They have to have LEADERS! ASSURERS! You can hire those-- all you want! Just bend over......

You gotta get off this kick, think for yourself, TAKE YOUR MIND inside that speaker VC, and DECIDE WHAT'S GOING ON IN THERE YOURSELF.

Of course, you CAN measure it. But WHY? Your MIND is more accurate-- it CAN SEE IT!

---Dennis---

 

RE: curious..., posted on July 3, 2012 at 09:33:53
Ralph
Manufacturer

Posts: 2188
Location: Minnesota
Joined: April 24, 2002
 So are you saying you used a heat-sensing gun?

 

RE: curious..., posted on July 4, 2012 at 00:06:56
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007

Yes, I have borrowed them. I wasn't willing to part with $150,000 or more just to "prove" what I know already exists.

But I am curious-- always-- so when I got a chance to borrow the whole diesel engine diagnosis tools-- which I had used before, but only on engines-- I got right after it. I've posted on this before.

It's no big deal. It's there-- the VC heat-- it should be-- that's obvious.

I didn't change anything in amp design because of it-- I had already designed amplifiers to have high transfer factors throughout-- the reasoning was simple-- keep the input signal intact until it reaches the room. That's all. I wasn't into changing the signal in any way, and I wanted to lose as little of its character as possible.

The result was many, many direct-thinking approaches-- with the idea of maximizing signal expression-- that is, not attenuating anything, and not re-routing or changing anything's essential character.

This, of course, automatically eliminated all coupling devices, and dictated Direct-Coupling. That was easy. Then, that's what we do.

Next? Well, we can't allow signal attenuation, so we have to have the best wires in the amp. That's also easy. Simply contact Siltech or an equivalent, keep your wiring short, and keep it away from bad influences. Hint: shielding is ALSO a bad influence---.

Of course, we can't allow signal compression to take place in the driver stage, so we have to have plenty of extra current-on-demand available WITHOUT power supply voltage-drop, and we want PLENTY OF GAIN. Why not? You think maybe I might wreck an entire amplifier by adding an extra amplification stage to it? NO WAY! That's almost as bad as Linestage Preamps--- whoops! There goes most of the music!

Nawwwwwwww----- I don't think I'll fall for that! Another easy, obvious thing-- since we can't have a power supply changing-- drooping under momentary load, and then re-charging out-of-time with the music signal, we have to minimize capacitance in power supplies in order to lessen its horrible effects on signal, and choose very fast, wideband caps. That's easy--just contact Mundorf, Rel-Cap, Wima or Dynamicap. There are a FEW others....

Of course, a large plate current draw on the input stage makes that stage impervious to small signal input, rendering music less fun because micro-dynamic details are missing. So? Use a low-plate current driver, and find an output tube that THAT driver can drive, because any other kind of driver will be sub-standard. OK-- that was easy-- done.

Let the thing pull less than one milliampere, but provide it with a 160 ma. plate supply, and then run 40 ma. of it to ground thru a resistor. That was also easy! Now it regulates without a regulator! SO? I like it.

Why won't I use a voltage-regulator or a Constant-Current Source instead? That would regulate the driver. SURE-- it will regulate the fun right out of your music! BUT-- on a poor power supply, it IS better than not doing SOMETHING.

But we don't have to do anything stupid here, just let the shunt-load regulate the driver PS-- and we're done. Good regulation with NO regulator, and NO CCS.

There! Like I said, it was SIMPLE.

What happens when these ideas all come together and drive a speaker? It makes more music-- at higher SPLs on MUCH less watts.

Well, I Ok with that! Now, I can, and do-- listen to music all the time-- leave equipment on-- and I get no heat problems, and no tube failures. You wanted 20,000- 40,000 hour tube life didn't you? I did-- otherwise, I'll buy Solid-State-- HEY! I'm easy!

Just let it play the music and don't bother me. I'll go thru it about every 6 years or so-- just for kicks.

Do I need to measure the heat in the VC? Well, most people sure need to! Do I? NO! Very little is there!

Anyhow, heat-sensing equipment is available at CAT, Detroit Diesel, and Cummins engines, and, of course, at NASA, and of course-- at your fave E-E College-- maybe. Are they into books or are they into creativity?

Maybe they hit a nice balance of both. You got one like that-- maybe you could attend it?

Of course, in the case of excess heat in the VC, it should be obvious-- so just know it's there and design equipment that doesn't contribute to it.

After all-- didn't you want the other bonuses too? Better clarity, speed, precision, better detail, much better musical layering, much more look-see into performer's minds, hearts, emotions, attitudes and intentions.

Why not? Decide what you want to reproduce and then design equipment that will do THAT. In my case, it's everything-- all that is in any kind of music.

And why not? If it's good music I like it-- any kind. If it's bad, I don't-- any kind.

Just design your equipment so it does what it's supposed to do-- AND NOTHING ELSE. Now, isn't that easier than driving people crazy, asking for this and that, when what you really need is clear thinking?

---Dennis---






 

RE: curious..., posted on July 4, 2012 at 08:16:06
Tre'
Industry Professional

Posts: 7965
Location: So. Cal.
Joined: February 9, 2002
 "Yes, I have borrowed them. "

Weird answer.

Do you mean that you borrowed a heat heat-sensing gun and ran tests on the speaker VC using different amps while you had it?

Shouldn't your answer have included the structure of the tests and the results in a somewhat normal way?

Maybe not. :-)

Have a great 4th of July Dennis!

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: curious..., posted on July 4, 2012 at 09:25:07
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007

It's HOT out here (Paradise Valley, Montana).

It's been this way for weeks-- these are intermittent hot winds that are mostly from Nevada, etc.

Well, finally, it's just sucked most of the moisture right out of the ground. In forested regions, or in heavily grassed areas-- where we raise a lot of Cattle-- both kinds of areas had grown a lot of underbrush-- and grass-- just before the hot winds.

This is kinda wild on my place where I have lots of grass below heavily timbered areas with underbrush.

Today, for the first time this year, I should be able to install pick-ups for gravity-fed sprinklers. I set it up years ago to get about 85 PSI, and can run several 1" hoses. The idea is to keep everything wet around buildings, etc.

So far, I got lucky-- no lightning. I gotta get ahead of it-- and can now do it.

You too have a good 4th, TRE.

---Dennis---

 

RE: curious..., posted on July 4, 2012 at 10:20:04
Ralph
Manufacturer

Posts: 2188
Location: Minnesota
Joined: April 24, 2002
 Not to put too much of a point on it, so, you *borrowed* one of these heat sensing gun thingys.

Then you used it to run a variety of amplifiers, all running the same power output, though the speaker, then measured the heat of the speaker?

Did you use a sine wave for a certain period, or a certain track on a recording? Both?

So- did you let the speaker cool off between tests? Did you chart any of the data? I'd be interested in seeing it; I've been looking into the relationship of the amp and the speaker for a long time.

 

RE: curious..., posted on July 4, 2012 at 15:39:19
tube wrangler
Manufacturer

Posts: 1363
Location: USA
Joined: January 29, 2007


Well, let's see: Yes-- I borrowed the whole engine diagnostic lab. (the use of it).

Yes on all of number two.

Both, and square wave also. Most telling is just to run a known recording for a set period of time at a standardized AVERAGE SPL.

I had the lab for a few days-- it was a weekend, so I ran a different amp every time I came into the lab-- after it had been quiet for a time.

I might mention that heat buildup in the VC quickly gets out of the way once power is off. It also quickly dissipates during listening if you switch from one amp to another that contains more on-time music signals and less out-of-time-sequence power.

Once we realized that we could do this, we were able to run through more amplifiers-- if one had allowed TOTAL cooldown-- say overnight, then we could not have run them all.

The solution was to subject SOME amps-- the ones we really liked-- or had showed up really bad, and we thought that one should get a re-run, then those examples would get run in the morning-- when all had not been running, or afternoon if we had chosen to let things stop for a few hours.

Most of that extra attention was not really needed-- if you just switched amps while running-- and equalized SPL levels for each one, you could quickly observe temp. differences. Actually, once familiar with the procedure, I liked doing it that way better.

It was really cool to put on a better amp and watch the temps drop-- then, just for kicks, crank things up-- see how loud we could get before we saw the higher temps again. To me, that was fun, and running amp changes during play was even better-- as we could see temp changes occurring as we played.

All that was necessary was to calculate the watt levels going into the speaker-- at the same SPL, and watch the temps change! Real cool.

Amps ranged from 2% heat all the way up to 97% heat. The second best amp that was tested was a WAVAC from Japan. It had a positive-bias, A2 output stage-- a DHT that was High-Mu.

The data remains informal (but scientific to me). I make no claims about it, and so am keeping it non-published. I only mentioned the heat% in VCs because I think it helps us to understand that a music signal must be presented to a speaker in time-correct form, or it will produce mostly heat. You'll still be able to drive the speaker-- but the ultimate in fidelity will not be achieved, and you'll need far more power to get the same SPL..

I think that the stage that drives the output device must be designed for the speaker to be used.

I regard (conceptually) an output stage not so much as an amplifier-- I regard it as a slave-- a modulated coupling device that is between the power supply and the speaker.

It is transferring the driver-stage's characteristics into the speaker at a higher power level.

You must match the driver-stage characteristics to the speaker. All the output stage should do is program power supply energy into the speaker in absolute conformance with the driver-stage's dictates..

This statement explains why a low power amp can out-power a much larger amp IF the low-power amp has a lot of Power Supply energy available. All that is happening is that the output tube is sampling that High-Power PS-- what you HEAR is that High-Power Supply-- the output device may only be capable of a watt or so-- but it can momentarily couple a MUCH LARGER PS into the speaker when that is called for.

The driver stage is critical-- it cannot be allowed to mis-program the output stage/power supply/speaker combo.

Most decent amps outputs can connect well to a speaker-- within reason-- within their types range.

In a SET amplifier, it is the driver stage behind that, and the power supplies behind all the active devices that determines-- mostly-- what we hear from a speaker.

---Dennis---

 

RE: energy loss and wiring..., posted on July 5, 2012 at 07:34:24
deathtube 667
Audiophile

Posts: 540
Joined: November 25, 2010
 Most designers don't think about how to mitigate the loss of energy as it travels inside the amplifier.

I guess that is why most use a single run of 22ga OFC hookup wire instead of the Siltech wires or multiple runs of TCCS.

Did the engineering studies you conducted confirm that the concept of transfer efficiency actually were measurable in some way?

dt 667

 

RE: energy loss and wiring..., posted on July 5, 2012 at 07:42:52
drlowmu
Manufacturer

Posts: 7401
Location: East of Kansas City
Joined: January 10, 2005
 YES.

Jeff Medwin

 

Thanks. I wonder if you have seen this, posted on July 5, 2012 at 09:13:23
Ralph
Manufacturer

Posts: 2188
Location: Minnesota
Joined: April 24, 2002
 -

 

RE: curious..., posted on July 5, 2012 at 10:02:47
Banat
Audiophile

Posts: 223
Location: near Belgrade / Serbia / Europa
Joined: February 5, 2010
 Hi Dennis !

Here is my few comments and personal conclusion to yours topic :

a)- You say all that things about that different amps produce different level of generated heat on the (load)speaker VC .
b)- And you say that musical signal have to be presented in correct time in to the load(speaker).
My personal conclusion is that both of yours observation is correct ! , but I think that both effects is also very tightly connected to the amp Slew Rate characteristic , respectively to amp output power signal Rise time speed rate vs. amp output power signal Fall down time speed rate characteristic .
Performing famous 10Khz square wave signal amp test you can only partially check that , since the real music signal have quit different shape .
c) You say - I think that the stage that drives the output device must be designed for the speaker to be used.
My personal conclusion that this yours claim is here correct to , but is also tightly connected to implementation of DC coupled driver tube to the output device ( triode ) ,in order to achieve the best possible amp sonics , but anyway I think you have to take care where that output device (triode) tiny grid peak music signal AC currents actually flow & finish , I think it is always better to be directed via to the load(speaker)rather than to goes somewhere else .
d) You say -I regard (conceptually) an output stage not so much as an amplifier -- I regard it as a slave-- a modulated coupling device that is between the power supply and the speaker.
Roughly speaking You are correct here to , but don`t forget that between output device and load(speaker) is OPT , placed like pasive impendance matching device , then you have there bias network circuit around that output/driver devices to , and ...etc , things which usually if is have not designed in proper way can worse the amp sound significantly .
On the end I must say next to :
Personally I`m not the big fun of SE(T) amps ! , but I like & support open mind people like you who want to goes forward and try to make modern & better sounding tube amps following self intuition and ears , but have non conventional design approach to .
And just this to :
I observed that in the far past times many succesfully top SS amps designers have borrowed ideas, concepts & solutions from the early best sounding tube amp designs.
For example :
Mr. John Lindsley Hood has made in the early 60` his famous 10W A class SS amp directly copying famous Williamson PP tube amp concept , later in early 70` many top USA & Japanese SS amp designers have directly copying Futterman OTL tube amps original design solutions , in the recent time many top SS amp designers Worldwide have copying even OTL Circlotron tube amps designs solutions .
Today if I made analysis of relative good sounding & modern SS amp original circuits I can found there many valuable design solution for modern & better sounding tube amp to , so I suggest you to sometime check this advanced SS amp circuits .
And yes , IF is possible attach here your amp schematic ,presented even with out of particular elements values , because if your amp really sound good than no matter what I or anyone else here think , writes ,praise or criticize , final judgement well come from yours customers ears anyway .

Best Regards !
__
Enlightened Evolution-Astral Projection

 

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