Bias Problem

[Structo]

This is how I bias my D'lite and ODS amps.

[ampfab]

I like this sound city bias circuit.

[ToneMerc]

Hi Phil,

it would be safer for the tubes to receive the raw bias directly through a resistor, and then andjust through a trimmer going to ground (raw bias - resistor - bias tap - trimmer - resistor - ground).

This way if the trimmer has some troubles the tube is biased to raw bias (so cold) instead of very hot (or unknown) using that schematic.

Yeah I have my dual bias circuit set up like that with the addition of a cap on the wiper of each bias supply. That BN dual bias scheme is not the best setup.

TM