Of course. So, I use global negative feedback a lot with high open loop gain and width bandwidth open loop gain. Because for me it is easy, simple, and cheaper. But it is only for me, right now. Because every one have different level of skill and idea.
These are all admirable achievements but i cannot see how they relate to the enjoyment of reproduced music.
For some weird reason there are very few (none?) successful high end amps built upon the high global nfb idea. Why can this possibly be? Is it possible listeners are so clueless they prefer natural tonality, dynamics and unmolested leading edges to engineering perfection? 😱
Blanket statements don't fly. What is considered musical is obviously subjective. I note that recording studios use what works for them. In one instance, someone had the bright idea to use a high end valve amp for monitoring because it was supposedly more musical. It got sidelined to the cupboard.
And with this comment we have officially left the rational engineering world and entered the subjective realm of BS town.
It is possible that many people are so clueless they think tonality, dynamics and unmolested edges cant be achieved with global feedback. And many "high end" amps can not do the above.
Because most engineer do not understand human perception in general. They only care about them self only. They usually do not want to learn how to listening, so they do not understand the correlation between perception and measurement.
On Dadod's 200W MOSFET CFA
Attempting to categorize a topology as good or bad is a waste of time. There are many valid solutions. As for feedback, copious amounts are used in mic amps to good effect.
No philosophy, 100% technical. Speaker is 2-way device: electro-mechanical, but also mechano-electrical. This means that all speaker acoustic distortion, harmonic, IM, multiple decaying resonances, etc. is converted by voice coil into electric signal that feeds into amplifier's input via feedback loop, to be amplified. Simply said, feedback amplifies speaker's acoustic distortion.
No, it does not fix speaker's errors, it just does not exaggerate them, as feedback arrangement does.
All points questionable.
Tube amplifier without negative feedback can achieve low distortion, fraction of a percentage point.
Feedback loop causes amplification of speaker's errors. No feedback, just speaker error. With feedback, speaker error plus speaker error further exaggerated by amplifier. Motional feedback is only marginally good at main speaker resonance. Because cone or diaphragm cannot be made absolutely rigid, MF will never mitigate acoustic distortion at higher frequencies, it will rather exacerbate it. Notional feedback is utopia from practical standpoint.
I don't want to be misunderstood. I am not trying to assault the basic principle of NFB. It is unquestionably good thing if you regard an amplifier loaded with a resistive load, which is not a source of error
But speaker is source of error OUTSIDE the loop, and NFB amplifies this error.
But speaker is source of error OUTSIDE the loop, and NFB amplifies this error.
That is wrong. The amp nfb will not correct the speaker error since it is outside the loop. It will NOT amplify it.
The article discusses ways to assess the stability of an amplifier when a small signal is applied to the output.
Conclusion: a well-designed and properly adjusted amplifier is stable. Unlike the rest 🙂
А. Витушкин, В. Телеснин. Устойчивость усилителя и естественность звучания.
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Conclusion: a well-designed and properly adjusted amplifier is stable. Unlike the rest 🙂
А. Витушкин, В. Телеснин. Устойчивость усилителя и естественность звучания.
??????«?????»
It WILL amplify it. Consider this. You have NFB amplifier with speaker at the output. No input signal. You give cone a sharp mechanical pulse, which will excite multiple mechanical resonances (as of waterfall plot)
These vibrations will be converted by voice coil into their electric equivalents, and NFB loop will feed this signal into amplifier's input. Due to mechanical delays, theamplified signal, especially at higher frequencies, will not cancel the original mechanical vibrations. What you get will be original vibration with superimposed signal delivered via the NFB loop.
If your enjoyment of music depends on using feedback or not, well, what can I say? Maybe a good psychiatrist ? 😀
Jan
Really? Well, in my book, that's horrible. This is 2020.
I don't suppose you could explain such a weird claim? If the speaker is outside the loop, how can it do anything to it (suppress or amplify).
Jan