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Old 9th April 2012, 01:44 AM   #11
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Hi anli, Thank you for your thoughts. Yes, I agree it is always a subjective opinion. I am using a Pedja AD844 IU, so in this case we have a similar reference point. I am listening to modern blues these days and some rock. Thank you, Dave
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Old 9th April 2012, 08:43 AM   #12
anli is offline anli  Russian Federation
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R2, R4+Q3, R9 and R12 are for taking part of dissipating power form appropriate active elements. Q3 (as well as many other schematics elements) is also for increasing of input elements output impedance for better PSRR.
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Old 9th April 2012, 08:45 AM   #13
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Quote:
Originally Posted by anli View Post
...for +/- 2 mA input: schematics and "harmonics' SPL". I have designed it to be used (and it is in use) with PCM63.


Why the addition of Q3 and R4 seems Q4 would see a low impedance from Q7 without them.

And also how do you handle dc offset I do not se any servo.

Last edited by Tazzz; 9th April 2012 at 08:50 AM.
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Old 9th April 2012, 08:59 AM   #14
anli is offline anli  Russian Federation
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About servo. To my taste both IU and amplifier must be true DC (while any servo is HPF). This opinion is a result of multi-year true DC audio-chain using. The schematics is balanced except for output follower. As a result, thermal drift is slightly above 2 mV/C, or less than 0.1%/C - it is useful to present in percents to avoid drift-phobia
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Old 15th April 2012, 05:06 AM   #15
regal is offline regal  United States
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Quote:
Originally Posted by jcx View Post
sorry but EF are 100% negative feedback circuits - check EE textbooks instead of Audiophile rags ad copy
Feedback is needed in a SS discrete UI, at least if you want less distortion than a simple passive I/v + tube. Its a hard pill to swallow for some but I have never seen a NFB free bjt UI that has less than ~-80db 2H, bjt's aren't linear enough without nfb.
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Old 20th February 2014, 06:13 AM   #16
anli is offline anli  Russian Federation
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Quote:
Originally Posted by regal View Post
Feedback is needed in a SS discrete UI, at least if you want less distortion than a simple passive I/v + tube. Its a hard pill to swallow for some but I have never seen a NFB free bjt UI that has less than ~-80db 2H, bjt's aren't linear enough without nfb.
(marked as bold by me) He-he... There aren't (and, I guess, will not appear already) trustworthy psychoacoustic tests proving any correlation between this understanding of "linearity" and "our ears understanding of linearity" (or, if we a saying about our ears, of naturalness).
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