In Reply to: RE: McIntosh C20 Pre-amp Right Channel Buzz posted by Triode_Kingdom on May 21, 2025 at 20:27:20:
Hi Triode,
thanks for taking a look. I first tested by putting the "hot" side of the volume pot to ground, the side connected to the loudness pot. The buzz still persists, though is just slightly weaker and completely goes away when nearing full volume.
I checked for voltage leaks on those caps. They were replaced, but figured I would check anyway. 19.5 volts at the pins and no voltage on the side of the .022 cap going to the wiper of the volume pot.
There really isn't much after this just the .47s which I replaced and the RCA's themselves.
The solder joints look good on the new volume pot, I'd be surprised if the issue was at the pot itself.
I noticed the original wires that run from v7 to the .47's is just plain wire that is twisted left and right side together. McIntosh did not use shielded wire here, would that have been better to use there? Unsure if RF is getting in there, but there isn't much between the volume control and the output connections.
I really appreciate the help
Jeff
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Follow Ups
- RE: McIntosh C20 Pre-amp Right Channel Buzz - mr9iron 00:24:38 05/22/25 (1)
- RE: McIntosh C20 Pre-amp Right Channel Buzz - Triode_Kingdom 07:38:43 05/22/25 (0)