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Prune 7th September 2003 07:06 AM

for headphones
Hey, can this be modified to an X amp???

Nelson Pass 8th September 2003 01:39 AM

Anything with a differential pair input stage can be mutated
until it is an X amp. In this case, the mutation is not trivial.

BTW, just becuase a "servo" is not directly in the feedback
loop does not mean that it does not affect the sound.

tschrama 8th September 2003 08:44 AM

But Gilmore's amp runs openloop... so it would require some modification of the gain of each stage to alow some global x-feedback .

Or do you would the feedback to stay local? Then the modification would only be around the two input stages ala x-bosoz, wouldn't it?


Prune 8th September 2003 09:29 AM

By openloop do you mean no global feedback? There is global feedback -- in the block diagram under the schematic, showing the bias opamp, the feedback goes into -I through the 10K resistor.
Nelson, he didn't write that the sound is totally unaffected by the servo, just that it's a less significant effect.

Actually I'm more interested in another Gilmore amp that I want to build: this one; could this be easier to mutate into a SUSY design?
(I know I asked this in another post, but there wasn't a complete diagram; also sorry about errors in this one)

jwb 14th September 2003 07:41 PM

This amp design is very weird. The "Servo" is very much in the feedback loop. Just because it runs at an extremely low frequency, doesn't mean the amp has no feedback. The author somehow feels that modulating the current on the front-end is somehow better than just modulating the negative input, but doesn't provide any evidence regarding that. You could replace the whole servo setup with a pot, adjust it once, and be done with it.

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