|
This is not a stacked B+, there is a separate 145v B+ already from the power supply.
Dan (ctc17) was thinking it maybe a hum cancelling circuit. Feed the ripple in from the audio out plate B+ to the cathode to modulate the bias. there is no cathode bypass cap in the circuit, just the 180 to ground, so you have negative feed back from the unbiased cathode resistor AND hum bucking from ripple off the power supply.
Last edited by DaveWM; 08-03-2012 at 10:00 PM.
|