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Old 28th August 2012, 08:22 PM   #441
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Right, if for example headphones can wait one minute staying alive.

Stuart, please stop banging in widely open gates.
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Old 28th August 2012, 08:25 PM   #442
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Come on... This ideas were implemented long before Wavebourn was born. For example, steam machines contained stabilizers of sped of rotation that used weights on springs.
That would be considered non-analogous art...
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Old 28th August 2012, 08:38 PM   #443
wayne is offline wayne  United States
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Well, you are going to stand alone with this, Richard. The VERY IDEA of not using a servo is artificial. The effort, in many examples, to eliminate either the servo or a feedback capacitor, is just too much to make the best possible audio quality.
Let me give an example:
About 15 years ago, I visited a company called Threshold, then located down in Southern California.
It was apparently the successor of Nelson Pass's Threshold.
They built a very formidable solid state power amp, that they INSISTED be DC coupled without a servo. What they had to do with parts selection and temperature controlled adjustment was FORMIDABLE! They put MORE effort in device selection for low drift than virtually anything else in the design. Then, they went out of business. Did not surprise me at all.
I think this was the big IGBT amps. DC coupled no servos and the IGBT's from Toshiba (short lived). Nice parts those IGBT's oscillations and thermal runaway.
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Old 28th August 2012, 08:42 PM   #444
bcarso is offline bcarso  United States
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I think this was the big IGBT amps. DC coupled no servos and the IGBT's from Toshiba (short lived). Nice parts those IGBT's oscillations and thermal runaway.
Rich May once told me that the use of DMOS in the output stages of Sumo amps, when he was there at the time, was primarily a marketing decision.

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Old 28th August 2012, 08:43 PM   #445
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Originally Posted by dirkwright View Post
That would be considered non-analogous art...
Mechanical, chemical, biological control systems work on the same principles as electronic control systems. Electronic control systems include other aspects, for example thermal.
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Old 28th August 2012, 08:43 PM   #446
RNMarsh is offline RNMarsh  United States
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The potential problem with INTEGRATING the servo into the design, is that you get the SAME downsides of an external servo, without the ease in DECOUPLING the servo to really be just a DC offset control.
Only if you have a particular design you are thinking of. it can be done well.
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Old 28th August 2012, 09:07 PM   #447
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Wavebourn,
I actually appreciate your analogies, I have been around steam engines and I appreciated that thought. Your statement that control functions can come from other aspects of physical devices is very true and not just in electronics.

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Old 28th August 2012, 09:18 PM   #448
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Originally Posted by Wavebourn View Post
Mechanical, chemical, biological control systems work on the same principles as electronic control systems. Electronic control systems include other aspects, for example thermal.
I was speaking from the perspective of my career as a patent examiner for the U.S. Patent and Trademark Office. In the patent world, they are considered not analogous. I would never look in steam engines for a control scheme of an opamp and it would never hold up upon appeal.

So, what you consider analogous is not what I consider analogous.
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Old 28th August 2012, 09:25 PM   #449
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Yes,
But Apple seems to think that they invented the rectangle with rounded corners. Nothing to you personally but the patent office is very confused these days about what is unique and what is plainly obvious and per-existing.
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Old 28th August 2012, 09:28 PM   #450
RNMarsh is offline RNMarsh  United States
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Come on... This ideas were implemented long before Wavebourn was born..
yes. so? You have added a way to impliment a servo in an amplifier circuit -- as i am asking for. Accept the credit/compliment.

I am interested in the practical application to a real audio amp circuit, of course. Can you show it in a working circuit so others can make it if you dont want to -- or at least talk in more detail about the proposed appl to a circuit which can have new ideas generated from it and so it can be applied to other toplogies.... [sorry got my manager hat on.] -RNM

Do you or anyone have an idea on how to do this to JC's favorite topology?

Last edited by RNMarsh; 28th August 2012 at 09:33 PM. Reason: Application of old ideas as new way -
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