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PostPosted: May 1st, 2020, 9:22 am 
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This is a quote from a noted industry leader. If I told you who is was you would laugh, well maybe
anyway please explain cathode degeneration

"To master an art we must first learn the broadest of concepts before we turn to the specifics.
Funneling from the broad to the specific finds its advantage in extending the possible. If you were designing a circuit and wanted to open the sound up, you might know to increase emitter or cathode degeneration values to get there. That knowledge would serve you well. But, a broader understanding of what you’re doing would likely take your design farther because there would be more options available.
The broad concept is that lowering feedback opens sound. Understanding the broad then allows you to choose specifics, each with differing results. If by degeneration we get one flavor. If by loop values, yet another. Both lower feedback, each sounds very different."


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PostPosted: May 1st, 2020, 9:49 am 
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Pelliott321 wrote:
This is a quote from a noted industry leader. If I told you who is was you would laugh, well maybe
anyway please explain cathode degeneration

"To master an art we must first learn the broadest of concepts before we turn to the specifics.
Funneling from the broad to the specific finds its advantage in extending the possible. If you were designing a circuit and wanted to open the sound up, you might know to increase emitter (transistor) or cathode (tube) degeneration values to get there. That knowledge would serve you well. But, a broader understanding of what you’re doing would likely take your design farther because there would be more options available.
The broad concept is that lowering feedback opens sound. Understanding the broad then allows you to choose specifics, each with differing results. If by degeneration we get one flavor. If by loop values, yet another. Both lower feedback, each sounds very different."


This is above "my pay grade" and I would request that David Berning jump in -- as I understand it -- cathode degeneration by virtue of the cathode resistor is a form of local feedback.

The reason so many amplifiers may sound better with little or no feedback is as we discussed regarding motional feedback -- that nasty time delay and after-the-fact correction. Of course you need an amplifier to be linear and stable to begin with to be able to pull it off

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PostPosted: May 1st, 2020, 9:54 am 
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He contradicts himself... He says increasing degeneration opens up the sound (specific case) but then says that lowering feedback opens up the sound (general case). But, increasing degeneration INCREASES feedback... :angry-banghead:

Roscoe

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PostPosted: May 1st, 2020, 10:09 am 
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At first, it appeared to be Tom P., because he uses real purty words. But by the end it was obvious. It's Steve, isn't it?


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PostPosted: May 1st, 2020, 11:50 am 
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Stuart Polansky wrote:
At first, it appeared to be Tom P., because he uses real purty words. But by the end it was obvious. It's Steve, isn't it?



WOO-HOO! :crazy:

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PostPosted: May 1st, 2020, 2:16 pm 
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I will never tell
but I would like to understand it


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PostPosted: May 1st, 2020, 2:23 pm 
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Regardless of whether you think more feedback is good or bad, it's tough to understand a statement that's not internally consistent...

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PostPosted: May 1st, 2020, 3:13 pm 
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I have had two amps that had adjustable feedback. I seem to always prefer the least amount unless the recording was really bad.
Turning up the feedback seem to make the nasties to get pushed back, and overall sound more pleasant. On good recordings turning up the feedback took the life out of the presentation.

What I did not understand in the quote was the reference to cathode degeneration and what that had to do with feedback.

Think the quote was not talking about global feedback.


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PostPosted: May 1st, 2020, 3:42 pm 
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Cathode/emitter/source degeneration is local feedback, rather than the more commonly used loop/global feedback.

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PostPosted: May 1st, 2020, 6:35 pm 
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So every tube in the amp has this local feedback. Seems like a bad choice of words


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