[Milsurplus] TCS crystal oscillator possible tube sub.

[Kenneth G. Gordon]

I think if I had a TCS, I would substitute a 6K6 for both the oscillator tube and 
the buffer tube (filaments are in series) and add resistors to the tube sockets 
to correct the voltage.

It uses the same base connections as the 12A6.

I'd add a 16 ohm 5 watt resistor in series with each filament. Or a single 32 
ohm 10 watter in series with both.

The 6K6 filament requires 6.3 V at 400 mA and the tube is shorter and 
skinnier than the 6F6 so it should fit.

Keeping in mind that one must use a crystal cut for 1/2 the operating 
frequency...

I still have not been able to find an octal power pentode with a 12.6 V 
filament equivalent to the 12A6.... 

Rats!

Ken W7EKB