Walt Jung biasing opamps in class A

[pucho812]

I read a comment referencing Walt Jung and how he had an article about biasing opamps( example 5532) to be class A operation.
That all you had to do was add a resistor to the opamp output going to the negative rail.

Does anyone have any details on this or the article the reference in the comment?

I would be curious as to what it achieves outside of heat increase?

 

[JohnRoberts]

I read a comment referencing Walt Jung and how he had an article about biasing opamps( example 5532) to be class A operation.
That all you had to do was add a resistor to the opamp output going to the negative rail.

Does anyone have any details on this or the article the reference in the comment?

I would be curious as to what it achieves outside of heat increase?

That was a popular audiophool tweak back in the 70s/80s trying to get something for almost nothing.

In theory forcing the output stage to operate class A at low level by sucking a bunch of current out of it sounds good in theory (to reduce crossover distortion), but if there was any real benefit to that, the IC makers could do it better and cheaper in silicon.

JR

PS; It has probably been discussed on this forum before (years ago), not necessarily as a Walt Jung thing, but general audio phoolishness.

 

[pucho812]

That was a popular audiophool tweak back in the 70s/80s trying to get something for almost nothing.

In theory forcing the output stage to operate class A at low level by sucking a bunch of current out of it sounds good in theory (to reduce crossover distortion), but if there was any real benefit to that, the IC makers could do it better and cheaper in silicon.

JR

PS; It has probably been discussed on this forum before (years ago), not necessarily as a Walt Jung thing, but general audio phoolishness.

So in your opinion, not worth it?

 

[JohnRoberts]

So in your opinion, not worth it?

Not as a general fix for every op amp in every circuit. Probably not for any.

I never took it seriously enough to do my own bench testing for the reasons given. The guys who design op amps are not slackers.

Managing crossover distortion is a well investigated topic by power amp designers too.

JR

 

[JohnRoberts]

I suspect one or more people have performed some bench testing wrt this. I'm too lazy to do a search.

JR