1967 Fender Bassman AB165: Oscillation on Normal Channel w/ bright switch engaged.

[cluster]

Hello Everyone, I need some schooling on oscillation. I have a 67 Bassman AB165 which is oscillating on the Normal channel with the bright switch engaged....

[PfeifferElectronics]

I have a new build of a blackface pro reverb. If I turn the reverb up past 4 or 5 it begins to oscillate. Ideas on what would be causing this?
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[priesty]

I've been building a Plexi copy a-la Kevin O'Connor's TUT3 Plexi. I have made it as close as possible to his suggested layout in the book (photo attached)....

[Agent_Smith]

Hi all!
I'm new here. Hope to have a good time here ;-) and hope you guys can help fixing my amp :-)

So, here I have this 80s Marshall...

[sir 6v6]

Hi guys
I´m having trouble with my diy fender champ (blackface)...
It is said to suffer from ultrasonic oscillation... I´ve tried to change...