John Curl's Blowtorch preamplifier part II

[john curl]

Thanks Gerard, for your very useful input. Now, does SYN08 know where the 4.99KHz is coming from? Also, everyone, please note the SYMMETRY of the first two (unknown) tones measured by Gerard, and noted on Fig. 3 from our paper, of 33years ago. 4.99-3.18=? 3.18-1.37=? Close enough for me.
Now what could possibly create these (unknown) symmetrical distortion products? Hint: FM is a good possiblity, AM maybe, but no creation mechanism has been developed for this, as of yet.
Thanks again, Gerard, you may have saved me a lot of time and trouble.

[brianco]

John,

The major problem you face here is not just blind conviction that all which was learned - often many years ago - was learned by rote, and often without fullest natural understanding - so that any challenge to a small part of the foundation of that which was subsequently built on that knowledge may just threaten the whole.

The spirit shown by those who put up argument against any novelty - or change of view-point - is rather similar to that of theological literal fundamentalists. (I was an Irish Episcopalian theological student in Dublin ....I know the signs of resistance to open-minded challenge. " It is written...." Usually with a

However I can understand that you rile people!!!! But clearly more gentle methods have failed. If the books have not given an answer does not mean that the question is invalid. Switch from an orthodox/acceptable viewpoint is the basis of quantum theory after all! The only one who is contributing as a real empiricist appears to be PMA. (Scott may have too much commercial pressure to totally disclose - hence, possibly, his reticence in talking on these matters with Dick S.)

[Lumba Ogir]

Hi Demian,
the overtones of musical instruments rarely are integer multiples of the fundamental frequency. Strings and pipes are inherently inharmonic. Inharmonicity can also intentionally be there for a desired expression. The sound spectra of clarinets have strong odd harmonics in in the low register (characterized by a mellow warmness).

The distortion mechanism in amplifying devices and circuits is well-understood. The audibility and perception of distortions are pretty well-understood. The pronounced disability of measuring techniques to provide conforming data is not widely well-understood.

[john curl]

Brianco, the voice of reason! I do wish that I could be more effective, but in my sorry state, I have experience, but not the energy, to 'prove' everything that I find useful.
PMA, a respected competitor, is surely on track to find the best way to do audio designs.
I had hoped that Scott could learn from another source, perhaps more effectively than from me, and pass it on. I certainly can't do it very well.

[scott wurcer]

Originally Posted by john curl

Thanks Gerard, for your very useful input. Now, does SYN08 know where the 4.99KHz is coming from? Also, everyone, please note the SYMMETRY of the first two (unknown) tones measured by Gerard, and noted on Fig. 3 from our paper, of 33years ago. 4.99-3.18=? 3.18-1.37=? Close enough for me.
Now what could possibly create these (unknown) symmetrical distortion products? Hint: FM is a good possiblity, AM maybe, but no creation mechanism has been developed for this, as of yet.
Thanks again, Gerard, you may have saved me a lot of time and trouble.

I'm taking a break from my trip preparations, for one comment. 11*3180 - 2*15000 = 4980 pretty simple math. If we can't read frequencies off of a 33yr. old mechanical chart recorder to 1% accuracy, you can't either. There is no mechanism for the creation of inharmonic frequencies, I'm beginning to think we are being put on.

[Nelson Pass]

Richard Brautigan, Scott?

[syn08]

Originally Posted by Wavebourn

It was in my previous answer to you, about power transfer. It seems to me you like to load current sources on opamp inputs in inverting modes. How linear is coupling between such thingies, and how good are overall parameters of such a combination?

It's pretty much irrelevant. A current source can be transformed, using the Norton theorem, in an equivalent voltage source, so a non-ideal current source maps to an equivalent non-ideal voltage source (having a non zero series impedance).

From this point, you already know the answer. The linearity is in no way better ot worse than the opamp open loop gain linearity, where the opamp is fed by a non-ideal voltage source. The source impedance may or may not matter, however I would say that for most practical cases the input capacitance nonlinearity is orders of magnitude lower than the (e.g.) Cb'c of the VAS device(s), subject to a large signal swing.

[syn08]

Originally Posted by john curl

PMA, a respected competitor, is surely on track to find the best way to do audio designs.

I would think that Brianco has also good chances to become a respected and appreciated high end audio designer, isn't he? He has all the required qualifications, including advanced Irish Episcopalian theological education.

[syn08]

Originally Posted by scott wurcer

There is no mechanism for the creation of inharmonic frequencies, I'm beginning to think we are being put on.

You are incorrectly assuming that we have an agreement about what "inharmonic frequencies" are.

[scott wurcer]

Originally Posted by syn08

You are incorrectly assuming that we have an agreement about what "inharmonic frequencies" are.

I guess, I mean 60Hz and 5kHz will never make 133Hz (at least not through nothing but a uA741).

Yes Nelson, though the quote gave it away. RB helped me escape from MIT (funny story).