DIY Princeton reverb won't develop negative bias voltage

[isaac_teller]

Hello. I have built a AA1164 exactly as per the schematic with the exception of a full wave bridge instead of a tube rectifier. All the voltages are where they should be except the bias voltage which jumps between 5-12 positive volts. I have tried both these bias circuits but neither one gives a steady negative DC voltage. What could be the problem? Thank you.


https://robrobinette.com/images/Guitar/Bassman/High_Voltage_Bias_Tap.pdf


https://el34world.com/charts/images/biascircuit2.gif

[sluckey]

That bias circuit will not work with a FWB rectifier. See my Scrapbook pages 8 and 9 for the correct circuit to use.

[isaac_teller]

I'll try it(the one on the bottom left on page 8) and report back.

[SILVERGUN]

I'll try it(the one on the bottom left on page 8) and report back.

Read page 9 if you haven't already

[sluckey]

I'll try it(the one on the bottom left on page 8) and report back.

Yes. Use the same values. The .047µF should be a Class X or Y cap, but you can use any .047µF @ 500V until you get a Class X.

[isaac_teller]

I hooked up the capacitive-coupled bias circuit and the amp works just fine now. Thank you Sluckey.