08/06/2025-17:28:46
(Modification du message : 08/06/2025-17:29:00 par Ragnarsson.)
RE: Technics SL-1210MK7+Audio Technica AT-OC9XSL+AT-LH11H
Douglas Self a écrit:
"I have designed many phono preamps
that were powered directly by 78/79 or LM317/337 type IC regulators, with no additional filtering.
In no case did rail noise or ripple make any detectable contribution to the output. To give this
some perspective, professional microphone preamplifiers work with signal down to −80 dBu,
which is 77 uV rms, and I have powered thousands of them directly from supply rails provide by
quite conventional power supplies, with no hint of a problem. They were of course balanced
preamplifiers, and this undoubtedly helps.
This immunity rail noise or ripple is very largely due to the excellent power supply rejection ratio
(PSRR) of opamps such as the 5532 or the LM4562"
"I have designed many phono preamps
that were powered directly by 78/79 or LM317/337 type IC regulators, with no additional filtering.
In no case did rail noise or ripple make any detectable contribution to the output. To give this
some perspective, professional microphone preamplifiers work with signal down to −80 dBu,
which is 77 uV rms, and I have powered thousands of them directly from supply rails provide by
quite conventional power supplies, with no hint of a problem. They were of course balanced
preamplifiers, and this undoubtedly helps.
This immunity rail noise or ripple is very largely due to the excellent power supply rejection ratio
(PSRR) of opamps such as the 5532 or the LM4562"