Sorry Esperado, I am talking about something you don't understand so we are done here, if you want to learn more about my amp ask the question in my thread please.
but he can afford to be deaf if need be
That was one of the moments of particular candor in the remarkable story in Rolling Stone (the audio journal of record) about Jimmy Iovine --- his admission of difficulties with his hearing, despite his assertion elsewhere in the article that he can hear what is wrong with something from a block away, or words to that effect. Much better than the strawmen of audio engineering, walking around in their white lab coats and holding clipboards.
As is, for many of them, the denial of, and refusal to be tested for, their hearing loss.
That was one of the moments of particular candor in the remarkable story in Rolling Stone (the audio journal of record) about Jimmy Iovine --- his admission of difficulties with his hearing, despite his assertion elsewhere in the article that he can hear what is wrong with something from a block away, or words to that effect. Much better than the strawmen of audio engineering, walking around in their white lab coats and holding clipboards.
Just as easy as it is to add a little DC Vos positive feedback to make almost any amp 120dB Aol at DC. Even the Otala amp, a very large resistor from the output to the appropriate point and suddenly the low OLBW goes away.
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Sorry, dadod, YOU don't understand what is a CFA. and your amp demonstrate-it*. I have still a lot of questions about them, but I work on this topology since 1970**. And you ?
* I don't say it will sound bad, do not confuse.
** With the same errors at the begining.
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In think Complete human hearing audio region is very critical ,
from quality definition of lowest bass spectrum ,via middle spectrum and up to highest treble spectrum .
That is the answer, but it's not insane: it's pretty readily achievable. Then the whole issue of whether or not to reproduce mistracking artefacts goes away.
Or use a local NFB around VAS/TIS, but in my CFA I don't do anything of this and have flat loop gain of around 80 dB up to 20 kHz(or open loop gain of 108 dB). All this with the proper compensation, and that is the amp Richard is saying it sounds so good.
There's definitely a region of our hearing that is more sensitive. So stacking our deck in that region makes sense to me. And, well, a low OLB integrator having the same loop gain at 20 kHz (or thereabouts) as a high OLB integrator does exactly that (and we're never doing WORSE over that region).
dadod, it seems you didn't understood my attempt. Neither try to understand what I said about my way to explore-it.
I was not criticizing your amp and don't want-you to be crossed against me.
I was just trying to explain why you don't see any difference with high or low impedance of your feedback path: your bandwidth is not high enough to see-it.
And you asked the question.
Your amp is a VFA with a IPS topology of a CFA. Nothing wrong as long as it sound good, but is is like this.
My English is not very good, that's why ? No need to be paranoid, neither to put yourself on the defensive. You are free of your choices.
By the way, I said your preamp was very brilliant, don't I ?
I was not criticizing your amp and don't want-you to be crossed against me.
I was just trying to explain why you don't see any difference with high or low impedance of your feedback path: your bandwidth is not high enough to see-it.
And you asked the question.
Your amp is a VFA with a IPS topology of a CFA. Nothing wrong as long as it sound good, but is is like this.
My English is not very good, that's why ? No need to be paranoid, neither to put yourself on the defensive. You are free of your choices.
By the way, I said your preamp was very brilliant, don't I ?
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One day, when I'll have the time to put it together, I'll show you a 2 pole compensated VFA (in fact, a slightly modified Lin topology) with the same high ULGF as yours and the same 80dB loop gain at 20KHz. Perhaps that will be the proof you need to understand there's nothing really special in your so-called CFA. Not the same SR, of course, but still 20x of what's required to avoid TIM.
I couldn't care less of Mr. Marsh's (or anybody else) CFA SQ comments, as long as they can't prove they can tell a VFA from a CFA in a DBT. Until then, the sacred cow is naked.
That will never happen, the years of listening are above reproach questioning them is just something that can not be.
scott, once again the question your answered was flawed (as habit).
Can-you make the difference between one of the AD or PMI OPAs and an other one ?
Probably yes.
Can-you name-it just by listening ? Surely not.
Now, if we make the same blind test between many pairs, VFA vs CFA and you note for each pair your preferences, is the statistic result can have a sens ?
Do-you think that we are all under some hypnotic influence of Mark Alexander ;-) ?
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No one knows exactly why CFA sounds better. The comments about what is audible is overly simplistic. A few paragraphs about phase and the ear is so old as to be Almost worthless as an aurgument. When we discussed this last year I put up a new book on hearing that was a summary of all the new info on it. JC bought it and started reading it. Hearing is much more complicated than a F-M curve or some phase data vs freq sens. Just as vision is much more complex than a few basic observations read off a chart of characters at a distance.
Eye glasses do not correct for everything in the world of vision perception and F-Munson curves, freq response, THD etc do not describe the whole of hearing perception. Both senses are much more sophisticated.
This gentleman's debate on why CFA or even why does DAdod's amp sound so much more real to sounds we hear and know isnt going to be solved this way. But setting aside the hearing or not of the amp.... it is a unique solution which combines the best of both CFA and VFA and should, IMO, be something to learn from.... he took a fresh 'open' look and thought outside the box. Nice job! So, let us at least try to understand it better. Maybe B.Cordell or others will find it suitable for inclusion in their book(s).
THx-RNMarsh
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