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Leakage on the input many times is the result of low plate voltage. The temolo intensity problem also suggests a shift in B+. Might just be a difference in mains voltage. Does the pilot light seem dim?
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Isn't it a bias tremolo..?Originally posted by loudthud View PostIn this forum everyone is entitled to my opinion.Comment
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Technically I would say yes. But not the power tube bias. It modulates voltage on the PI cathode.Originally posted by überfuzz View Post"Take two placebos, works twice as well." Enzo
"Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas
"If you're not interested in opinions and the experience of others, why even start a thread?
You can't just expect consent." HelmholtzComment
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Can someone enlighten me as to what this circuit is doing?!? (in yellow highlight) It looks problematic. I'd be inclined to remove that 10M resistor and see what happens. Maybe it was doing something when the chassis was only 0V and not earthed? Maybe the guy is using some kind of power conditioner with the ground on a big capacitor or even a ground lift adapter. That could put DC right onto the chassis with this circuit depending on how the footswitch is grounded.Attached Files"Take two placebos, works twice as well." Enzo
"Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas
"If you're not interested in opinions and the experience of others, why even start a thread?
You can't just expect consent." HelmholtzComment
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Huh, ops... True, I didn't pay close attention, the 10M resistor threw me off. Hm.. I don't get that one, what's the purpose of having it there?Originally posted by Chuck H View PostIn this forum everyone is entitled to my opinion.Comment
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It supplies the voltage that the LFOscillator requires to run.Originally posted by überfuzz View Post
A bit of overkill coming off of the B+.
But it is what it is.Comment
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I don't see how it's doing that.?. It's isolated from all B+ and bias circuits. The oscillator takes it's HV from the screen node. That's a 10M resistor from the final HV node to the footswitch jack circuit which terminates at the footswitch + lug between two caps in the phase shift circuit.Originally posted by Jazz P Bass View PostIt supplies the voltage that the LFOscillator requires to run.
A bit of overkill coming off of the B+.
But it is what it is."Take two placebos, works twice as well." Enzo
"Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas
"If you're not interested in opinions and the experience of others, why even start a thread?
You can't just expect consent." HelmholtzComment
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I think Loudthud may have solved this puzzle (kickstarter)Originally posted by Chuck H View Post
See here there: http://music-electronics-forum.com/t38979/#post378068Originally posted by Enzo
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I agree that this is a "kickstarter."Originally posted by g1 View Post
Note that, in the 5E9 circuit, the closed footswith turns the tremolo low frequency oscillator (LFO) OFF and the kickstarter voltage is positive.
In the blackface LFO the closed footswitch turns the tremolo LFO ON and the kickstarter voltage is negative being derived from the bias supply.Comment
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I just caught his addition to that thread. That must be it. I'd still remove it and see.Originally posted by g1 View Post"Take two placebos, works twice as well." Enzo
"Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas
"If you're not interested in opinions and the experience of others, why even start a thread?
You can't just expect consent." HelmholtzComment
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