But transformers can be slow (in comparison). What is "natural"? Surely a valve full of air is more "natural" than one with a good vacuum? Silicon dioxide on a sea shore is more "natural" than in an FET gate?ontoaba said:
This is just acoustic impedance matching. Horns can do this, but they can also introduce non-linearities and frequency response problems. Good engineering is the key.
Yes read Baxandall and then read the modern updates that show where his simplified model was incorrect, but still go on to show that different NFB ratios result in different proportions of Low Harmonic distortions to High Harmonic distortions.
These High to Low ratios of Harmonics seem to be related to sound quality perception.
These High to Low ratios of Harmonics seem to be related to sound quality perception.
Too little feedback creates high order products from low order distortion, but insufficiently reduces both. This has cropped up in several threads recently. Baxandall pointed this out decades ago, others too.
Small amounts of feedback are OK for adjusting gain and output impedance in an amp which has low distortion. If you need to reduce distortion then you need more feedback.
Small amounts of feedback are OK for adjusting gain and output impedance in an amp which has low distortion. If you need to reduce distortion then you need more feedback.
and not all of that increased feedback needs to be Global Negative FeedBack (GNFB)
I believe that Jan Didden has it at his website. www.linearaudio.nl
edit: I couldn't find it there, sorry. Maybe Doug Self's? Jan's site does have an apropos article by Scroggie.
edit: I couldn't find it there, sorry. Maybe Doug Self's? Jan's site does have an apropos article by Scroggie.
Open-loop gain is approx 70 dB at 20 kHz (and is basically flat over the audio range). If you want to have 40 dB of feedback factor you will end up with a closed-loop gain of 30 dB approx and an f3 slightly below 300 kHz with a phase-marging of 30 degrees approx. But this is under the assumption that a feedback network with linear frequency response is used.
By choosing an appropriate feedback network the phase-marging can of course be improved at the cost of HF extension (which would still be highn enough). A lowpass at thi input will also reduce ringing.
But I assume that this is the basis of a fine amp.
Regards
Charles
Ouch - I must be very slow in typing ! My comments refer to post #37.
By choosing an appropriate feedback network the phase-marging can of course be improved at the cost of HF extension (which would still be highn enough). A lowpass at thi input will also reduce ringing.
But I assume that this is the basis of a fine amp.
Regards
Charles
Ouch - I must be very slow in typing ! My comments refer to post #37.
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How phase margin of ~80dg. could sound more accurate then ~65dg.??? To have 65dg. of phase margin, in my opinion, is enough to have stable amplifier. Wiht TMC or TPC is hard to get much better phase margin.
dado
Yes bump that glass bottle with that rocks from sea, and it will sounds most natural.
Could you please explain that impedance matching in engineer language, or some link will appreciated. Is it possible to match that impedance from amplifier instead?
Hi, I have tried it with lemay's-ancetres at 02:14 at violin solo, it has very good from my laptop with a papercone. Could you please explain that too?
thanks alot,
Looks like the response of an amp using TMC.
Does it sound better or worse than no feedback or standard miller comp? I cannot answer that, but in the absence of an intelligent test (DBT), I will assume that the differences are small enough to be able still make the statement that, in good design examples, the average listener would probably express a preference, but it is unlikely that they would wright off any of the examples as 'terrible' or junk. And herein lies the key in my view. No need to get dogmatic because the differences do not warrant it.
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