Just built a 63 Brownface Vibroverb and everything is working great and sounding good EXCEPT.... with the Tremolo on and the intensity set over 3 or 4, I will get an oscillation/squeal.
My first thought is to replace the .01uF going to the Intensity pot.... or maybe the intensity pot itself?
I won't have time again to troubleshoot until next weekend, but wanted to get some of the expert's perspectives from you guys.
What are some of the things I should look at?
Tremolo oscillation squeal on Brownface Vibroverb build
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- kanderson70
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Re: Tremolo oscillation squeal on Brownface Vibroverb build
Lead dress on the wires running to the tremolo pots is critical. Push them around with a chopstick while running. Post photos if you can't sort it out.
I build and repair tube amps. http://amps.monkeymatic.com
- kanderson70
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- Joined: Thu May 17, 2018 12:09 am
- Location: NW Arkansas
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Re: Tremolo oscillation squeal on Brownface Vibroverb build
Disconnect the NFB wire from the speaker jack or board. Does it still squeal with the tremolo?
- kanderson70
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1 others liked this
Re: Tremolo oscillation squeal on Brownface Vibroverb build
Swap the OT primary plate leads and report back.
- kanderson70
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- Location: NW Arkansas
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Re: Tremolo oscillation squeal on Brownface Vibroverb build
Couldn't stand it. I had to tear into it tonight.
So I took Xtian's advice and tried the chopsticks... nothing. So I twisted the pair of wires from the Speed and Intensity. nothing.
Then I tried Steve's advice.
Bingo. Had to swap the two leads from the OT going to the power tubes.
Thank you Steve and Xtian! Working like a champ now, no oscillation squeals, and to tell you the truth... it even sounds better than before (even without the vibrato on).
Love this place
So I took Xtian's advice and tried the chopsticks... nothing. So I twisted the pair of wires from the Speed and Intensity. nothing.
Then I tried Steve's advice.
Bingo. Had to swap the two leads from the OT going to the power tubes.
Thank you Steve and Xtian! Working like a champ now, no oscillation squeals, and to tell you the truth... it even sounds better than before (even without the vibrato on).
Love this place
Re: Tremolo oscillation squeal on Brownface Vibroverb build
Steve wins.
I build and repair tube amps. http://amps.monkeymatic.com