RE: Preamp with high pitch whine from 1 channel

Posted by Cpwill (A) on November 2, 2015 at 15:02:31

In Reply to: RE: Preamp with high pitch whine from 1 channel posted by FenderLover on November 2, 2015 at 05:53:51:

I tried the preamp on with two different power amps, same noise, same channel. I also reversed the output IC's at the outputs and noise changed channels. I now have a different preamp installed with original amps and no noise; thus, I concluded it is the preamp. I have used 3 different 5687's same noise, same channel and I swapped the CF tubes channel to channel and same noise, same channel. The noise is a high pitch ring, unlike any microphonic tube I have ever encountered.

Next steps, all new tube is noisy channel, not just 5687 and CF, but also rectifiers, voltage reg and current reg tubes as well, clean all sockets, and hit all solder joints with hot iron.

There are grid stoppers on 5687 and CF. They measure correct, but maybe I should replace with higher values????
"Anyone who understands jazz knows that you can't understand it. It's too complicated. That's what's so simple about it." - Yogi Berra.

Cpwill

This post is made possible by the generous support of people like you and our sponsors:

Follow Ups Full Thread

Topic - Preamp with high pitch whine from 1 channel - Cpwill 05:02:49 11/02/15 (13)

Solved - Cpwill 15:30:28 11/08/15 (0)

RE: Preamp with high pitch whine from 1 channel - FenderLover 05:53:51 11/02/15 (3)

RE: Preamp with high pitch whine from 1 channel - Cpwill 15:02:31 11/02/15 (2)

RE: Preamp with high pitch whine from 1 channel - Triode_Kingdom 14:27:03 11/03/15 (1)

RE: Preamp with high pitch whine from 1 channel - Cpwill 14:32:52 11/03/15 (0)

RE: Preamp with high pitch whine from 1 channel - Chip647 05:18:42 11/02/15 (0)

RE: Preamp with high pitch whine from 1 channel - Blackdog 05:07:47 11/02/15 (4)

RE: Preamp with high pitch whine from 1 channel - Cpwill 05:17:20 11/02/15 (3)

RE: Preamp with high pitch whine from 1 channel - Blackdog 05:42:30 11/02/15 (2)

RE: Preamp with high pitch whine from 1 channel - Cpwill 11:00:20 11/02/15 (1)

RE: Preamp with high pitch whine from 1 channel - Blackdog 15:45:57 11/02/15 (0)

RE: Preamp with high pitch whine from 1 channel - FenderLover 05:05:02 11/02/15 (1)

RE: Preamp with high pitch whine from 1 channel - Cpwill 05:08:14 11/02/15 (0)

Follow Ups

RE: Preamp with high pitch whine from 1 channel - Cpwill 15:02:31 11/02/15 (2)

RE: Preamp with high pitch whine from 1 channel - Triode_Kingdom 14:27:03 11/03/15 (1)

RE: Preamp with high pitch whine from 1 channel - Cpwill 14:32:52 11/03/15 (0)

RE: Preamp with high pitch whine from 1 channel

Post a Message!