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In Reply to: RE: Hopefully, Mr Fraker will join us, as you suggested.... posted by tube wrangler on March 14, 2013 at 00:17:55
Dennis, how does increasing the ESL of a cap improve its performance*?Answer: It doesn't, and it can't.
What it will do is create a resonant tank. You are not advocating higher fidelity you are advocating creating HF spuriae that result in a sonic signature which is to your taste.
That's all well and good until you try to ram it down everyone's throat as the ONLY WAY to achieve TRUE MUSIC REPRODUCTION (your capstyle)
* BTW I shouldn't need to point out what part of your post will result in increasing the ESL of the capacitor.
Mark Kelly
Edits: 03/15/13Follow Ups:
The best gear does not use caps as signal coupling devices-- I have never used a cap in series with an audio signal, and do not intend to.
Capacitors are by far the sorriest sounding devices ever invented to use in the presence of audio signals-- if they're used in series with an audio signal.
I don't do that. Capacitors are ONLY used by myself in power supply design, and that is only because the A.C. power systems in our world require filtering if we're going to produce D.C. from A.C.
When you're modifying a piece of gear that does use capacitors as signal pass devices, then you're forced to get the capacitors to perform as well as they can musically-- something that no capacitor has ever done right.
Compromise becomes the order of the Day-- you do the best that you can with what's available in these sorry devices that cannot, under any circumstances, pass a musical signal without degrading it.
Which is why we build D.C. amps-- they ARE REQUIRED in order to reproduce music well.
The amp/preamp modifier doesn't have this luxury, so he is forced to search among the ruins, and try to assemble or find cap combinations that will at least limp along trying to reproduce music.
For most, it's no big deal. I simply gave the man a glimpse of what can be done if you need to do it. That's the most honest approach-- give a complete answer.
---Dennis---
> Capacitors are by far the sorriest sounding devices ever invented
> to use in the presence of audio signals-- if they're used in series
> with an audio signal.
Another piece of sheer nonsense. If it was true, almost none of today's measurement equipment would work because of distortions, noise, whatever. The person who states so lacks even very basic knowledge of electronics and physics.
In the Alice in Wonderland world that those people inhabit, none of the usual laws of physics apply. They invent crackpot "explanations" for real or imagined audio effects, and will never, ever, present a logical and reasoned reply when challenged on a technical point. The standard retreat is of the form that "we pros can HEAR the difference, so we don't need to give any supporting argument for the technical "explanation" that we previously claimed."
Chris
Until you do it isn't worth responding.
Mark Kelly
"I have never used a cap in series with an audio signal"
Dennis, that's not true.
A cathode bypass cap is in series with the audio signal, the plate signal current of the tube. That's very much in the signal path.
The power supply, the way you do it, is in the signal path so the last cap in the power supply is very much in series with the audio signal.
Just because the driver tube has it's plate directly connected to the output tube's grid does not mean there are no capacitors in the signal path.
With your circuit I count 4.
1. The driver stage cathode bypass cap.
2. The decoupling cap (last cap in the power supply just before the plate resistor) for the driver stage.
3. The output tube cathode bypass cap.
4. The decoupling cap just before the output transformer.
Please correct your post.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Yes! Tre, my post does need correcting.
What I meant to say, and should have clarified, is that a D.C. amp doesn't use coupling caps in the main signal path, which is true.
Caps are used in Power Supply functions, for cathode bypassing, and as filters in power supplies located as local nodes within the D.C. amp's layout-- power usage points all have local power supply development that uses capacitors.
That should cover all 4 points you mentioned, you are correct in all of them.
Caps are the "poor boy" in audio, performance wise. For this reason, we can at least eliminate them as main signal path couplers.
We can and should use the best caps we can find, and when those-- no matter how good, are not nearly good enough-- we are reduced to cap bypassing or buying super-expensive caps (Duelund CAST)in order to degrade the signal's bandwidth, dynamics, and transfer efficiency as little as we can arrange.
That is admittedly not perfect-- as no capacitor is. As always, you do what you can!
Thanks, Tre, for the heads-up. Consider my post corrected.
---Dennis---
Dennis, I appreciate you making that correction.
Please understand that there is no real difference between what you call the "main signal path" and the cathode bypass position or the decoupling position.
The audio signal at the grid of a tube causes that tube's plate current to change, to increase from the idle point and to decrease from the idle point. The plate current change is what causes there to be a output signal.
The cathode bypass cap is in series with the tube and all of the AC component of that plate current flows through the cathode bypass cap.
That cathode bypass is every bit as much in the signal path as a coupling cap is.
The decoupler (last cap in the power supply) is also in the main signal path in a single ended circuit for all the same reasons.
The cathode bypass cap, the tube and plate load are all in series with the last cap in the power supply and in series with each other.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Good explanation, Tre. Good.
---Dennis---
> What I meant to say, and should have clarified, is that a D.C. amp doesn't use coupling caps in the main signal path, which is true.
Nonsense. Cathode bypass caps ARE in the main signal path. You're just waffling now because, truth be told, you really don't know what you're talking about.
Or, to put it another way, a "good engineer," such as you claim to be, wouldn't have gotten himself confused over such a fundamental issue in the first place.
Stop dissembling and admit your thinking is a muddled mess. Not the mind of an engineer by any stretch of the imagination.
You have no business passing judgment on anyone. Go away.
-Henry
No offense meant Henry, but what are you smoking?
---Dennis---
Dennis is no engineer and has absolutely no right to claim that he is, in his attempts to neutralize opposition from real engineers. He is at best a dilettante, dabbling in audio but avoiding proper in-depth engagement. No doubt I shall be damned as a wrecker of the forum, but so be it.
Are you and Henry sharing the same------ stuff?
You better check-into a rehab center!
---Dennis---
I am not a junkie and I doubt if Henry is either. You really should refrain from making libellous statements.
I have to agree with Benie. The mud slinging is regretable, and I realize I'm pushing the limits of what's tolerable. On the other hand, I do believe what I'm saying is true, and the nasty tone is due to having become totally frustrated trying to have a productive two-way discussion with these clowns.
No, I'm not on drugs, If you really think I'm out of my mind -- well, that's a lame rationalization on your part, Dennis.
Dennis: Read everything I (and others) have written. Ignore the name calling and focus on the facts. People are trying to send you a message. They are tired of being lectured to and told that everything but your formula is crap. Some of us are fed up with your calling yourself a superior engineer and then posting undeniably nonsensical techno-crap.
Seems to me (and a lot of other folks who prefer not to comment) that a dialog with you and Jeff is really a monologue. What did Mark say? You never respond to the topic, except with more one-way preaching. Is your heart really broken? Try to understand, what you said about the forum being taken over by people with no common sense and no tolerance for different ideas -- many of us would agree, in another context, we could have used exactly the same words to describe you and Jeff.
We are trying to teach you something here. In short, get off your high horse and figure out what the community is trying to tell you. Stop playing the victim (and the savior). It's neither needed nor wanted.
-Henry
"Capacitors are by far the sorriest sounding devices ever invented to use in the presence of audio signals-- if they're used in series with an audio signal.
I don't do that. Capacitors are ONLY used by myself in power supply design, and that is only because the A.C. power systems in our world require filtering if we're going to produce D.C. from A.C."
Of course, the power supply itself is in the audio path, and so the final capacitor in the power supply is essentially "in series with the audio signal" too.
Chris
Hi Mark,
I see nothing in the above post which "rams it down your throat "
as you quote :
"That's all well and good until you try to ram it down everyone's throat as the ONLY WAY to achieve TRUE MUSIC REPRODUCTION (your capstyle)"
It may be Dennis' capstyle, but it certainly isn't what Dennis was emphasizing in his most informative post above. I just re read it twice!!
I see you are listed as a manufacturer Mark, what exactly do you make in the audio world? Myself, and other Forum Members would like to know.
Jeff Medwin
I don't respond to your posts.
I'd appreciate it if you didn't respond to mine.
Mark Kelly
"It may be Dennis' capstyle, but it certainly isn't what Dennis was emphasizing in his most informative post above. I just re read it twice!"
How many times did you re-read Sam Tellig's explanationof the Stereophile doggie CD? And you still couldn't understand it.
He makes sense.
-Henry
He makes three phase turntable motor controllers.
And, as you say, sense.
He is also the most educated mathematician the AA has.
I don't think any of us have a big enough slide rule to go toe to toe with Mark.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I've posted this before, but it always makes me laugh.
A long, long time ago, one of my former colleagues, a signal processing engineer named John Stach, wrote a little haiku. I think it's hilarious.
Supposedly, a haiku is a three-line poem composed of 5-7-5 syllables and having something to do with the seasons. I know this is a poor definition, but it's crucial to the humor of the poem. To wit:
Two parallel plates
And a spring together ring
Forever high-Q
LOL.
-Henry
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