Edcor Tranny Selection

[SteveH]

All,
For my from scratch ST70 I want to go with Edcor OPT's. So I see that the stock A470 comes in @ 4300ohms, Edcor makes a 4200ohm flavor; which I assume would be fine. However, should I go for something abit higher ? They make a 6600ohm version in the same rating that I can go to; Im just not sure what the benefit would be ? Im pretty sure I just want to stay with the 4.2k one, as I intend on running EL34/6l6/kt88 stuff.

Thanks !
Steve

[EWBrown]

If you're running EL34s, 6CA7, J/J KT-77, KT-88, 6550, etc stick with 4300 ohms (4200 is fine, and anything between 4K to 5K is fine). 6L6GCs will work with 4300 ohms, though higer P-P impedance may fare better with these.

For 6L6GCs. KT-66s, 6600 ohms would be a better match. The grid biasing voltages will also have to be changed (less negative) as well.

/ed B in NH

[SteveH]

Thanks Ed !