Pretty much, yes. As in the feedback working in the same way, accomplishing the same function.
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Pretty much, yes. As in the feedback working in the same way, accomplishing the same function.
I'll let them explain it best... it's their science, but it does make sense..
https://www.passlabs.com/technical_article/audio-distortion-and-feedback/
That embarrassingly shows that he doesn't really understand feedback beyond what was known back in the 1960s (pre-Otala, TIM and SID).
Right, and in both cases, to counter the poor noise performance? But aren't class D very low noise to begin with? so why the negative feedback?
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Thanks, I've read that before. I'd simply refer you back to the Putzleys paper @Julf and I have already posted.
Yes, too little negative feedback may theoretically raise higher-order harmonic distortion to a level at which it becomes more audible. But the levels of feedback used in quality amps push these higher order harmonics orders well, well below any conceivable threshold of audibility.
Look at one of Putzeys' more recent amps. The SINAD is so high that, for distortion to reach zero dB (absolute threshold of hearing in quiet), the signal would need to be at such a level that seconds of exposure would cause permanent hearing damage.
It would indeed be very embarrassing to think that a guy legendary in the amplifier business and who runs one of the most successful companies in audio knows less about solid state amp design than an anonymous forum member on the internet
Ok, gotta run for a while... debate later.
Better read Bruno’s article. I think you have some significant misunderstanding about feedback.
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The main objective of feedback is to reduce distortion.
For me, as an engineer, that what he says makes less logical sense than that said by other gurus.
I live by logic, rightly or wrongly.
Nelson is very smart. Don’t judge him by his marketing output.It would indeed be very embarrassing to think that a guy legendary in the amplifier business and who runs one of the most successful companies in audio knows less about solid state amp design than an anonymous forum member on the internet
Ok, gotta run for a while... debate later.
Feedback mostly deals with linearity/distortion, stability and output impedance, not noise.
I know a lot of people who run very successful companies without having much clue about how their products really work on a technical level.
I would recommend judging opinions based on their factual content, and not based on how "legendary" the person uttering them is.
100rounddrum
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This thread can be closed. All Tube and solid state amps sound exactly the same.
Me too.
Whether a player is very musical was evident on a 1960s portable mono record player and still is on modern laptop speakers.
Musicality has absolutely nothing to do with sound quality.
Assuming controlled gain and low distortion are inherently in the design, you don't need a lot of negative feedback is my point... isn't to say you don't use ANY negative feedback... but if you need a lot of negative feedback, what does that say about the basic design of the amp? and the gain control? In extreme cases, you can get square waves, vs controlling the amount of open loop gain.. or am I totally misunderstanding what I remember learning about operational amplifiers? (as I've said on a dozen occasions, I am not a professional engineer)..
just seems like common sense that you shouldn't have to intervene as often with a good design vs a bad one.
just seems like common sense that you shouldn't have to intervene as often with a good design vs a bad one.
Please read the Bruno Putzeys paper I linked to.
Not all.
Wideband transformers are very difficult to design and make, so a lot of valve amps, particularly less expensive ones have loads of bass distortion, some just have lots of distortion but it is presumably euphonic.
There are plenty that do sound the same though, making an expensive purchase not needed for accuracy.
I will, and I've already seen this... sounds like there is a major philosophical divide here (shocking) between some engineers and others..
Just to be clear, I'm aware that even McIntosh use negative feedback in solid state amps ... not about whether to use or not, it's about how much as it can introduce other issues if too much is needed/used...
this is a quote from my MC462 owners manual.
"Every stage of voltage or current amplification
must be as linear as possible prior to the use of
negative feedback. McIntosh engineers know how to properly
design negative feedback circuits so they contribute to
the extremely low distortion performance expected from
a McIntosh amplifier. The typical McIntosh owner would
never accept the approximately 100 times higher distortion
of many non-feedback designs"
this is a quote from my MC462 owners manual.
"Every stage of voltage or current amplification
must be as linear as possible prior to the use of
negative feedback. McIntosh engineers know how to properly
design negative feedback circuits so they contribute to
the extremely low distortion performance expected from
a McIntosh amplifier. The typical McIntosh owner would
never accept the approximately 100 times higher distortion
of many non-feedback designs"
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What issues are introduced if too much is used?
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