Hi All - Just finished putting together a brownface Princeton - pretty much stock layout except I used individual filter caps instead of a can and my PT is a bit beefier - 325-0-325 - voltages measure about where a Blackface Princeton would be. Seem ok on first glance, though I'll probably look to drop the B+ a bit.
So - here's the problem - plays fine and sounds good when the tremolo is on - no funny noises or parasitics, tremolo works seemingly perfectly - but, as soon as I ground the tremolo to stop it, I get this funny Atari/theremin sounding noise - loud - varies sort of randomly with the volume knob - starts kind of high then drops in pitch - it really sounds like playing Pole Position - sort of "biiiii-ewwwwww"/fart.
Read somewhere that V2 can be demanding on tubes being both part of the PI and the oscillator - tried 4 or 5 different 12ax7s in there (Svetlana, Groove Tubes, and a Tung Sol - all known good) - same with all of them.
Disconnected the NFB loop - didn't make a difference.
Anyone else ever run into this? Any thought?
AJ2000
So - here's the problem - plays fine and sounds good when the tremolo is on - no funny noises or parasitics, tremolo works seemingly perfectly - but, as soon as I ground the tremolo to stop it, I get this funny Atari/theremin sounding noise - loud - varies sort of randomly with the volume knob - starts kind of high then drops in pitch - it really sounds like playing Pole Position - sort of "biiiii-ewwwwww"/fart.
Read somewhere that V2 can be demanding on tubes being both part of the PI and the oscillator - tried 4 or 5 different 12ax7s in there (Svetlana, Groove Tubes, and a Tung Sol - all known good) - same with all of them.
Disconnected the NFB loop - didn't make a difference.
Anyone else ever run into this? Any thought?
AJ2000
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