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In Reply to: RE: pissin match posted by tube wrangler on June 28, 2012 at 00:20:25
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.
Follow Ups:
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---
Edits: 07/02/12
So are you saying you used a heat-sensing gun?
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---
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
Everything we're talking about can be measured. The thing is-- at what price?
Test equipment costs a lot. Arranging personnel and setting up experiments to be scientifically valid is very expensive and horribly time-consuming.
Fortunately, I know a few engineering talents at Universities where I have been a student-- and I know folks from the Oil, Mining, Power and Timber businesses, not to mention Cattle Ranchers.
All of these folks are no fools, although they may differ in both approach and perceived results. Most can afford, and do have-- outstanding home music systems.
All of these people are helpful and will pitch-in and help me when I need it. I'll do it for them also. Set up a new system, or get an existing one better sounding. Then, again, I might just help fix fences or rebuild a tractor engine, or the kid's Motocross Bike. I might wire up Diesel Power for a Mine-- whatever. Neighbors and friends. A strong people who know what they're doing, and are creative and inventive.
None of that need matter to you if you'll just take a hard look at a wiring and component layout.
Just look at it. Where are the Bottlenecks? What is in the way of something else-- or worse, may be shielded by it, it may be in a magnetic or a static field, or it may be mounted at a wrong angle-- to something else.
A wire may be too long. A wire might be near another wire-- or worse, dressed against metal (chassis, etc), or it might not be floated in interior space in the right dimension. Some idiot might have used shielded wire instead of using a single run of-- say-- Siltech LS-38, and then floating it physically where it has to go.
Maybe the chassis isn't deep enough to allow 3-dimensional mounting of parts-- that sucks! (Fix it)-- and is causing it to distort whatever part is mounted in it.. Maybe the chassis is made of wood or plastic instead of steel or brass. Maybe it's aliminum and the guy doesn't get it-- aluminum isn't for High-Voltage circuits! It really sucks up H.V. and deals with it in ways that you don't want in your music!
If steel (excellent), maybe the guy didn't use enough brass to isolate all the iron components..... Maybe the thing isn't heavy gauge-- maybe it's a Tin Can. Well, then it will sound like a Tin Can!
Is there anything in the circuit model that impedes the flow of musical energy. In the cables, in the interconnects. In preamps (UGH! PREAMPS!! What musical short-circuits THOSE ARE! Besides, they're obsolete-- ancient artifacts). Today we have source components that can drive amps direct.
Just look at it! What do you see? THINK! Where are all the energy bottlenecks? How do you fix ALL of them?
Then, just go to work and build the whole thing right. It is very gratifying because every time you make something better-- the sound gets A LOT better.
Transfer efficiency is a kind of grab-all term meaning that your losses have been minimized, and your energy flows are not being slowed down, phase-distorted or current-starved, or bandwidth compromised any more than is absolutely necessary in order to use a component that will do what you want in all other ways..
You just let things flow unimpeded, so music is also able to do that.
---Dennis---
Dennis,
Great essay.
Unlike most other builders, who deal with "proven" textbook formulas from decades ago, you are giving us "concepts" to apply to our amplifier designs.
Thanks again, for helping the modern builders here on AA tube forums.
dt 667
Thank you Dennis. I read everything you write. You help me think!
YES.
Jeff Medwin
Did Dennis mention what instrumentation or process he used to prove his transfer function theory in the lab?
dt 667
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.
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---
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
Wow! All the Way from Yugoslavia! You guys are Oil Dudes!
Welcome to my rantings and (shall we call them discussions?-- yeah, that's better, I think)-- your post is a delight....
Hidden in it are all kinds of cool observations-- you realize, of course, that there are people on here who won't understand a word of it!
To those dudes, I'd say-- "get out more"-- travel! Even within the USA and Canada. Amazing what people are doing-- you just have to find them.
Realize that Americans have had a strong media complex for many years, many of our industries have been geared to already set-up production goals, schedules, etc., and the almighty Dollar has called a lot of the shots.
It's really nobody's own fault, but many of us over here have completely lost the ability to think for ourselves, having become Robots for the System.... Likewise, some "Engineers" have become basically Office Dudes--who use test instruments and known and proven theory over independent thinking.
However, those guys also contribute in meaningful ways to many things, but as a whole, our people have become programmed mentally to the point that they are actually blocking progress, invention, and individual expression on many levels.. THIS in the "Land Of The Free"! Totally amazing. Stand shocked-- and look.
It's a pleasure to find you on the net-- with your unorthodox writing style. Keep it up-- many of us are enjoying this-- your instincts make total sense to me.
A bunch of us are going to show up at Denver's RMAF 2012-- in Room 2020.... and go from there, visiting as many of our fellow exhibitor's showrooms as possible. The whole point is to see how others are doing audio-- not just ourselves.
Keep up your posts-- they're way cool!
---Dennis---
-
~!
The Mind has No Firewall~ U.S. Army War College.
Thanks, Ralph! I read all of it. Thanks for the insightful glimpse into how human beings operate under the stress of making things look good to whomever is judging them!
Historically, that's mostly how we got our audio "engineering" specs-- from politicians! Not only political politicians-- "engineering" politicians!
Same methods! Develop formulas, specifications and applications that make the-- Mistakes Of The Time-- look good on paper.... Of course, those formulas always work and always deliver the results scientifically expected of them-- they accurately deliver the OPINION of the guy who developed the formula!
What the Heck! We somehow manage to stumble around and a few of us think for ourselves, and actually get part way back to physical reality--sometimes, when we can.
GUYS! You will get a Kick out of Ralph's paper-- read it and understand what life on this Planet is really doing to our minds-- as the "experts" in every field tell us how to think, how to engineer-- and how to die their way-- as fools!
We can do better. And, when pushed, we'll do better yet. After you read Ralph's insightful paper, you'll realize why only a few will do it!
---Dennis---
"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"
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---
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