[Milsurplus] 801-A Substitute

[Richard]

If you need an 801-A today you're in for sticker shock, about $100. This 
is a long way from the 25 cent days when no-one wanted them. Anyway, I 
find a triode-connected 6L6 has the same amplification factor as the 
801-A, and is interchangeable.   I mounted an octal socket on top of a 
4-prong base with a 1.3 Ohm heater dropping resistor hanging out, and a 
wire from the cathode lug for grounding.  Using my TBW, I tested a metal 
6L6 with the can both grounded and ungrounded, a 6L6-WGB, and 5881, and 
all behaved exactly the same as an 801-A.

In the test, plate & screen voltage was 400 volts, but there is reason 
to believe it will work up to 500 volts.  The RCA tube manual says, "In 
push-pull circuits where grid No. 2 of each tube is connected to a tap 
on the plate winding of the output transformer, this maximum rating is 
500 volts."

Richard, AA1P