Yes, that was main part of your comment:
"You amp's compensation is way to complex to be analyzed by simple inspection. I've counted up to three feedback loops and four poles, then stopped. It appears to be some sort of output inclusive TPC, tamed at HF (where the output stage phase shift starts to be critical for stability) by a lead-lag pole-zero pair.
This would require capturing in a simulator and start analyzing each loop for stability and other properties. I'm afraid I don't have the time to go through this exercise."
John I think a good business manager could have been a big help. I suspect a fair amount was made on your work not just by you.
Of course, you are correct, but I really tried to make my own corporation, business partnership, VP of another corporation, and a consultant at large. It is tough to get a business type to work with you, who will NOT take the majority share. It is more than just business, it is also how much you want to charge the public for your efforts. I never asked for enough, when I was in charge.
It seems the ones that make money from audio are the ones that make designers work for them. Mark Levinson comes to mind.
Jan
This part was also very refreshing:
"so-called CFAs (in fact, in particular for audio amplifiers, a circuit topology that trades PSSR, noise, offset, CMRR, loop gain, etc... for speed)"
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Your Research
Richard,
This might be a pretty important research you are about to embark upon and I hope you document the hell outta it. complete with methodology, process,
plenty of pics and data that both support and can be explained or not and
those that don't support and can be explained or not.
Heck, this should be an AES research presentation of it's own.
The good thing Hopefully it will be finite., That is and answer of yes
we can find it and identify or not identify vice we can't find why it sounds
different.
In fact it might be more important that we realiaze at this time.
So extra notes in the logs please. And, as is your typical process
always validating and cross checking with your other instruments.
Good Luck Richard, this post will self destruct in 5 seconds
Richard,
This might be a pretty important research you are about to embark upon and I hope you document the hell outta it. complete with methodology, process,
plenty of pics and data that both support and can be explained or not and
those that don't support and can be explained or not.
Heck, this should be an AES research presentation of it's own.
The good thing Hopefully it will be finite., That is and answer of yes
we can find it and identify or not identify vice we can't find why it sounds
different.
In fact it might be more important that we realiaze at this time.
So extra notes in the logs please. And, as is your typical process
always validating and cross checking with your other instruments.
Good Luck Richard, this post will self destruct in 5 seconds
Just was it is on the homepage
FM 223 - FM ACOUSTICS LTD.
Price as far as i know is apx. 45'000 Swiss Franks plus Cables ( 2k), and you wait at least 6 Months after full payment in advance.
Difference to my 222 is de-click circuit, 100/120 Hz Notchfilter and improved modules, having better noise figures and maybe better soundquality.
http://www.diyaudio.com/forums/group-buys/268708-agi-511-preamplifier.html#post4202906
http://www.diyaudio.com/forums/group-buys/268708-agi-511-preamplifier-2.html#post4253786
Most have been covered multiple of times.
Regarding cal/adjustment, it is THE most important step but I hope you are able to differentiate btn the rational and the illusionary.
Take the paper you have linked to for example
http://www.diyaudio.com/forums/lounge/146693-john-curls-blowtorch-preamplifier-part-ii-6490.html#post4292523
George
I am reading the AG511 schematic.
Aren’t there any problems when directly grounding pins 1 and 13 of uA749?
(output is taken from pins 2 and 12)
http://www.diyaudio.com/forums/group-buys/268708-agi-511-preamplifier.html#post4202906
http://matthieu.benoit.free.fr/cross/data_sheets/UA749.pdf
George
Aren’t there any problems when directly grounding pins 1 and 13 of uA749?
(output is taken from pins 2 and 12)
http://www.diyaudio.com/forums/group-buys/268708-agi-511-preamplifier.html#post4202906
http://matthieu.benoit.free.fr/cross/data_sheets/UA749.pdf
George
Attachments
Those are current outputs so it doesn't really matter where you load them, as long as it is within the voltage rating.
Jan
Yes, Jan is correct. I see someone can get IC's to work.
I see it passed the noise test with bare undegenerated LTP's at the input, the power of feedback. Did Alvin mention TIM, I know PIM was not around yet?
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That's a very good idea John, and would really like to run my tests on such a close series. But where to find a user that has them all? My clout is not so big (yet) that they send a bunch to me on request
Jan
German Audio magazine did it: Ortofon quintet series test
Well, they measured each one of them and did a listening test. What else should be done?
Look at the upper left corner where you can browse through the pages of the test.
I met the elder Saul Marantz at the CES many years ago and it reminds me that he was concerned about the large number of different EQ characteristics used by record companies. To solve the problem Saul designed a preamp that incorporated many EQ curves. From that, his friends convinced him to go into production. It was called the Audio Consolette. Saul wasnt trained in electrical engineering and so Sidney Smith visited him and later the Audio Consolette was modified to reduce noise and the Model One was born. The Model One added RIAA EQ for the first time. Sidney stayed on to become chief engineer.
Might be interesting to measure one of those units to document the EQ curves.
THx-RNMarsh
Might be interesting to measure one of those units to document the EQ curves.
THx-RNMarsh
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Thank you Jan and Scott.
I will simulate the circuit to see what is going on because I don’t get it (not your fault).
George
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