by erichayes » Sun Dec 30, 2007 6:54 pm
I talked with Bob Pletka of Eurotubes about a year and a half ago regarding the "skinny pin" issue with the KT77s, and he said that all those shipped after September, 2006 will have the proper (for the US) pin diameter. They are basically "drop-in" subs for the EL34 as far as bias and plate voltages are concerned, even though it's a beam power tube--as opposed to the EL34's being a power pentode.
The KT66, being basically a mutant 6L6GC, will have to be rebiased to prevent self-immolation. You'll want to see somewhere around 48~50 mA cathode current per tube, which should happen when you have around -40 volts on pin 5 of the tube(s).
Eric in the Jefferson State