Bias-Vary Trem won't wiggle....

[DMichel123]

I've just built a 1x12 vibroluxish amp, and it works!!:eek:

Only one problem... I don't have any trem... Any Ideas where to start? Does the plate voltage on the trem tube have to be within a certain range?? Anybody know a good place to find info on trem circuits?

[Enzo]

If you copied the curcuit from Fender, then it ought to work. Most Fenders MUST gave the foot switch connected to get trem. IS your circuit like that?

[DMichel123]

Yeah, I copied it from the Brown Tremolux... when I found it wasn't working, I removed the CF, so it now resembles a Brown Deluxe trem circuit...

[Tom Phillips]

Both those amps use a trem oscillator circuit that stays ON when the footswitch is disconnected.
First you need to determine if the low frequency oscillator is running then trace the signal through the circuit. Here are a couple of links full of information which will help you understand and hopefully fix your tremolo circuit.

http://www.lynx.bc.ca/~jc/tremoloCircuits.html (http://www.lynx.bc.ca/%7Ejc/tremoloCircuits.html)
http://www.aikenamps.com/PhaseShiftOscillators.html

HTH,
Tom

[DMichel123]

Thanks, I had the switch grounded...

Now, I wanted a Hi-Lo input switch rather than 2 inputs, but can't seem to make it work, I guess it's not as simple as I thought... can anybody help??

[Richard]

Yes. It looks like you should wire the jack so the tip has a 1M resistor to ground and a 68K to the grid of the first tube. Then, get a single pole double throw on-on switch, connect a 68K resistor to the tip of the jack and to the center of the switch. Connect one of the switch's other terminals to ground and one to the input of the first tube. This will either parallel the 68K input resistor to give 34K or bleed the half the signal to ground through a 68K. You might try a SPDT on-off-on if you want an intermediate value.