by Bob Latino Sun Dec 14, 2014 5:21 pm
Hi JT,
I do not know how the bias system is set up with the GCI board and what is the value of the bias resistor? You did mention in a personal Email to me that this amp has individual bias controls for each output tube. What you can do (with the amp OFF) is measure the resistance to chassis ground at each of the four bias measuring points. If you get 10 ohms, then you bias each tube at .400 volts DC like a VTA driver board. If you get something other than 10 ohms, then the bias setting will be different than .400 volts DC.
Bob