Getting seriously irritated with "balanced amps". What is it ?

[infinia]

Did you ask Nelson Pass for permission to express his own views and opinions?

That's not what I did or need to do! I think I know enough to see that a designers (NP) philosophy isn't matching what you expressed.
Why don't you just look at Nelson's paper and think things through logically instead of confronting.

 

[Lumba Ogir]

Fanuc,
balanced circuits provide higher PSRR than single-ended circuits.
Balanced circuits cancel even order harmonics, thus reducing the measured distortion, without offering sonic superiority to the single-ended configuration, which desirably (re)produces both even and odd order harmonics.

 

[KSTR]

If you have an power amp (could be just VAS & O/P stage) with poor PSRR on one supply rail (say the negative) but good on the other rail (positive) would balanced signals help here (anti phase) if you used another identical amp with the same problem ? (bridged)

Depends. If those are complety seperate amps with their own supplies, then not very much. Only if the "bad" rail sort of impresses the identical error on both sides things get better -- and you need to ged rid of the ground current, therefore you need a common supply. This supply can be single ended (no need for dual rails) since there are no power currents on "ground". "Ground" turns into "reference" and should be decoupled (almost) only to the bad PSRR side of the amps, to lessen the effect (and letting the good side do more as it can do so). Quite simplified, of course.

Sidenote: For an easy example of how to handle this aspect of PSRR, look a the Ciuffoli buffer and compare what is different to the normal design:
http://www.audiodesignguide.com/PowerFollower/

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Originally posted by Wavebourn
I still don't get it Klaus. My opinion is, let me repeat, symmetry is desirable for more effective power usage. Period. Other reasons are actually means turned by mistake into aims.

I don't know if I understand you correctly.... in case perfect symmetry is a concern for its lack of a nicely staggering HD decay then you can still introduce some mismatch on purpose to dial in the right amount of even harmonics -- at least with low GNFB designs.

- Klaus

 

[Wavebourn]

That's not what I did or need to do! I think I know enough to see that a designers (NP) philosophy isn't matching what you expressed.
Why don't you just look at Nelson's paper and think things through logically instead of confronting.

I am not confronting, but you are. I've expressed my own opinion; you said that I am wrong because Nelson Pass wrote some paper.

It's not a discussion, infinia.

 

[Wavebourn]

I don't know if I understand you correctly.... in case perfect symmetry is a concern for its lack of a nicely staggering HD decay then you can still introduce some mismatch on purpose to dial in the right amount of even harmonics -- at least with low GNFB designs.

No, you don't understand me correctly.


My point is,
Symmetry of analog amplifiers is required for power consumption efficiency. As soon as power consumption is out of optimization equations symmetry is not required anymore.