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Old 16th October 2012, 12:13 PM   #28191
gk7 is offline gk7
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Quote:
Originally Posted by john curl View Post
...
What amazes me is WHEN I do introduce a new schematic (from me), I get virtually no response or follow up. ...
I for my part would like to see more of these:

Discrete Opamp Open Design

You mentioned "Perhaps when the time is right I can put the FIRST stage in, as well, as it is slightly different, and 3dB quieter, or so.
Anybody want to buy a slightly dated phono stage, that sounds pretty good, ..."

Yes, please ! :-)
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Old 16th October 2012, 12:21 PM   #28192
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Originally Posted by john curl View Post
Build a Levinson JC-2 (schematic released in 1977) or a JC-80 (schematic released here, recently),
.
.
What amazes me is WHEN I do introduce a new schematic (from me), I get virtually no response or follow up.
Maybe everyone interested in audio circuits knows Levinson JC-2 and JC-80?
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Old 16th October 2012, 12:25 PM   #28193
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Originally Posted by john curl View Post
Build a Levinson JC-2 (schematic released in 1977) or a JC-80 (schematic released here, recently), or copy a Parasound product, if you want to waste your time building it, instead of just buying it, and saving yourself both time and money in the process.
What amazes me is WHEN I do introduce a new schematic (from me), I get virtually no response or follow up.
I use to design (or modify existing equipment) and build by myself most of my own home equipment. As you, i believe :-).
Because the time i spend on it increase my knowledge and experience and is a pleasure in itself. And i prefer my last amp (Current feedback, >1000V/µs, very very low hd and IM) to any commercial amp i know, including the Levinson (i had one of them ).
Like you prefer your last design, i believe. Because they respond to something we are looking for at this moment, one more step.

It is easy to understand why it is not so easy to find people with enough knowledge in electronic to see the beauty of a design at first sight. But it is possible and full of benefit and pleasure. More pleasure to play music with other musicians than to make conferences about music.

Have a look at this thread: [COLOR=#0000FF ]http://www.diyaudio.com/forums/solid...-new-post.html[/COLOR]

to see how a valuable, creative and open minded engineer, full of modesty, can share ideas and designs on this forum and how people around can contribute to the evolution of a project up to a wonderful final realization.
It is an other economical system (open source), different of royalties and traditional business. And respond at the philosophy of a DIYer's forum.
It is in that kind of project that i would like to see you, because i know ( more than you can imagine :-) your work (including in some professional equipments, Ampex etc. :-) and loved the way they sounded and some ideas in it.
And because your experience is unique, like all experiences, and, so, irreplaceable.

We are both old, now. And we do not need more business or money. Time to share what life and work had taught us if we want our experience has some meaning, and recover the enthusiasm of our young years, see what i mean ?

.Yes, matching devices is realy boring... . But, as exotic parts are not in my religion, i' do not spend too much time anymore on this boring part, searching for providers and best deals. :-)
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Old 16th October 2012, 01:13 PM   #28194
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Originally Posted by john curl View Post
.........
I recommended a SERVO to remove the cap completely.
John,
I noticed that you use 1uF mylar in your integrators. Have you ever evaluated polycarbonate or polypropylene at that location? Any sonic improvements or is mylar good enough?
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Old 16th October 2012, 01:18 PM   #28195
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Not directly related to subject being discussed, but someone might find it interesting:

Flicker Noise In CMOS Transistors from Subthreshold to Strong Inversion at Various Temperatures:
www.ee.ucla.edu/~vis/pulica/pub1.pdf
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Old 16th October 2012, 02:25 PM   #28196
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Originally Posted by elektroj View Post
John,
I noticed that you use 1uF mylar in your integrators. Have you ever evaluated polycarbonate or polypropylene at that location? Any sonic improvements or is mylar good enough?
I have used polypropylene caps in servos for most demanding apps.
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Old 16th October 2012, 02:45 PM   #28197
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Yes, Esperado, I am old, but I am not wealthy. In fact, I have less in reserve than virtually all my friends and associates. Therefore, I must continue to design for others and live off the royalties that I get for my latest designs.
Publishing early, like patenting a new design idea, does NOT help the limited in resources. The big companies just take your design and run with it, usually not even giving recognition to the originator of the topology. This happened to me 1/3 century ago, when Ortofon took my JC-1 design that was patented and made their own version. The very version that Mark Levinson and I were trying to license to them for about 5 years previously. They just 'laughed' when I objected in writing, but I was helpless. Lesson learned.
Esperado, where is your studio located? Paris? Did or do you know Gunther Loof! I used to work for him, many decades ago.
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Old 16th October 2012, 04:28 PM   #28198
bcarso is offline bcarso  United States
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Quote:
Originally Posted by elektroj View Post
Not directly related to subject being discussed, but someone might find it interesting:

Flicker Noise In CMOS Transistors from Subthreshold to Strong Inversion at Various Temperatures:
www.ee.ucla.edu/~vis/pulica/pub1.pdf
Good ref! Viswanathan wrote a letter that helped me get a major promotion, for which I am most grateful to this day. Very nice guy.
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Old 16th October 2012, 07:05 PM   #28199
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Did or do you know Gunther Loof!
I had meet him in the Bernard Estardy studio (CBE), so long time ago. Is his still alive ? He was older than I.
OOT, i'm not wealthy myself, and no reserve, A freak and careless life ;-)
I don't own or work in any studio anymore (i'm retired) and i have stopped to work as a free lance sound engineer in the musical area during the 80s.
Bored with disco, samplers, and synthesizers everywhere.
After that, i had worked for the audio movie and TV post production business as a mixer and technical manager, and design equipment for some companies like AKAI (DD1500 project; a well known virtual recording and editing machine), mostly in the digital domain and analog parts around. I had began my life as an engineer in the research and department of the most important HIFI French manufacturer at that time.
I was in head of a big PA company, for a while, too. So many concerts all over Europa.
The interesting part of my life: i was always in the same time in electronic and musical production ... mechanical engineer and pilot in the same time.
End of OOT

...
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Old 16th October 2012, 07:41 PM   #28200
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Very fast bipolar CFA designed for high PSRR at high frequencies may sound great, I agree. Tough competition to JFET miracles
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