A must read on negative feedback

[tomp]

This article summarizes much of the "old wives tales" about negative feedback. It is worth going through some of the technical details.

https://linearaudio.net/sites/linearaud ... ume1bp.pdf

[Cogito]

"Hey numbskulls, listen to me......."

is the gist of the article ...

[Pelliott321]

The article is beyond my feeble brain to comment on it.
I have owned two amplifiers that had adjustable feedback and they always sounded best with the control set to minimum.

[Yeeterkeeter]

"Hey numbskulls, listen to me......."

is the gist of the article ...

Oh lord, not another one of these

[tomp]

I also sent this article to a very smart friend of mine who used to work at Bell Labs and here is his reply:

Yes, this is a great piece! I happen to have a pair of the Purify amp modules, designed by Bruno Putzeys, in the bass channels of my system amp, and they do a great job. He’s a really bright guy, and of course he is right. Negative feedback in power amplifiers has gotten a bum rap for many years, primarily triggered by the writings of Matti Otala way back when, and a following of many folks with no sound engineering background. This seems to be an unfortunate repeating sideshow in the world of often just hyped high end audio products. Negative feedback, records v.s. digital, tubes v.s.solid state, etc.

The high end audio debate goes on. Here is a piece I wrote at the request of Jan Didden, the new Technical Editor of audioXpress that may help clarify what Bruno was getting at.

Attachments

Negative feedback basics 2.pdf

(27.46 KiB) Downloaded 323 times

[tomp]

Here is another response to the article from a very smart speaker designer who also uses amplifiers with negative feedback. It pays to look at all sides of the arguments, not just dismiss them out of hand because they might conflict with your preconceived notions.

Great write up. Doesn’t open with the typical divisive bias and is a learning experience for the reader.

One to archive for sure.

[SoundMods]

Negative feedback gets a bad rap because of implementation. If you want to know how to do it right - -take a very close look at Peter Walker's Quad II amplifier.

[tomp]

Some of the early solid state amplifiers were perfect examples of trying to fix bad basic designs with lots of negative feedback. The results were terrible. But, knowing how to build a basically good circuit and then doing the negative feedback the right way has positive results.

[Cogito]

I also sent this article to a very smart friend of mine who used to work at Bell Labs and here is his reply:

jj?