model 20 hum (detector circuit?)

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model 20 hum (detector circuit?)

Tubesforme
Member

Posts: 107
Threads: 20
Joined: Feb 2015
City: Los Angeles, CA

#18

10-25-2015, 12:40 PM

(10-25-2015, 10:57 AM)OZ4 Wrote: I thinking the hum is coming from the power supply. Try hanging a about 20uf cap on the bias line coming from the power supply to ground.

It isn't the filters as they have now been replaced three times, each time with a different brand, but of the correct value. I put a 10uf across the output capacitor and then tried the input with no change. Extra filtering isn't the answer.

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Messages In This Thread

model 20 hum (detector circuit?) - by Tubesforme - 10-19-2015, 01:11 PM

RE: model 20 hum (detector circuit?) - by Steve Davis - 10-19-2015, 03:40 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-19-2015, 06:23 PM

RE: model 20 hum (detector circuit?) - by Steve Davis - 10-19-2015, 07:03 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-20-2015, 10:01 AM

RE: model 20 hum (detector circuit?) - by mikethedruid - 10-24-2015, 07:04 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-24-2015, 09:24 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-27-2015, 03:58 PM

RE: model 20 hum (detector circuit?) - by Alan Douglas - 10-24-2015, 07:23 PM

RE: model 20 hum (detector circuit?) - by mikethedruid - 10-24-2015, 11:48 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-29-2015, 06:21 PM

RE: model 20 hum (detector circuit?) - by Steve Davis - 10-25-2015, 12:01 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-25-2015, 12:46 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-28-2015, 08:14 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-30-2015, 07:30 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-25-2015, 10:57 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-25-2015, 12:40 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-25-2015, 11:39 AM

RE: model 20 hum (detector circuit?) - by Kenneth F. Besso Jr. - 10-25-2015, 08:01 PM

RE: model 20 hum (detector circuit?) - by morzh - 10-25-2015, 11:08 PM

RE: model 20 hum (detector circuit?) - by Steve Davis - 10-26-2015, 08:38 AM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-26-2015, 10:18 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-27-2015, 12:14 AM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-26-2015, 10:34 AM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-26-2015, 11:24 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-27-2015, 12:12 AM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-27-2015, 08:43 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-27-2015, 11:38 PM

RE: model 20 hum (detector circuit?) - by Steve Davis - 10-28-2015, 12:25 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-28-2015, 01:12 PM

RE: model 20 hum (detector circuit?) - by Ron Ramirez - 10-28-2015, 02:34 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-28-2015, 08:07 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-28-2015, 11:52 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-28-2015, 01:08 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-29-2015, 07:50 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-28-2015, 03:36 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-28-2015, 08:03 PM

RE: model 20 hum (detector circuit?) - by Ron Ramirez - 10-28-2015, 09:10 PM

RE: model 20 hum (detector circuit?) - by radiohenry - 10-29-2015, 07:31 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-29-2015, 07:44 PM

RE: model 20 hum (detector circuit?) - by LASJayhawk - 10-29-2015, 07:57 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-29-2015, 10:10 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-30-2015, 07:21 PM

RE: model 20 hum (detector circuit?) - by LASJayhawk - 10-29-2015, 10:36 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-30-2015, 01:28 PM

RE: model 20 hum (detector circuit?) - by LASJayhawk - 10-30-2015, 03:29 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-30-2015, 03:34 PM

RE: model 20 hum (detector circuit?) - by klondike98 - 10-30-2015, 04:24 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-30-2015, 06:13 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-30-2015, 07:04 PM

RE: model 20 hum (detector circuit?) - by OZ4 - 10-31-2015, 10:40 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-31-2015, 02:06 PM

RE: model 20 hum (detector circuit?) - by Ron Ramirez - 11-08-2015, 10:28 PM

RE: model 20 hum (detector circuit?) - by Tubesforme - 11-09-2015, 08:11 PM

RE: Low continual hum in model 21 - by Steve Davis - 10-23-2015, 10:34 PM

RE: Low continual hum in model 21 - by Tubesforme - 10-23-2015, 11:19 PM

RE: Low continual hum in model 21 - by Steve Davis - 10-24-2015, 12:01 AM

RE: model 20 hum (detector circuit?) - by Tubesforme - 10-24-2015, 06:50 PM

Need correct voltages for det and af model 20 - by Tubesforme - 11-07-2015, 05:54 PM

RE: Need correct voltages for det and af model 20 - by morzh - 11-08-2015, 12:09 PM

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