[R-390] Variacs and solas: additional thoughts

[Flowertime01 at wmconnect.com]

Todd Roberts asks, can using a variac possibly extend the life of the 3TF7 
ballast tube? 

No not likely. The best thing you can do for the 3TF7 in the circuit is to 
leave the receiver on forever. (Well, 24 x 7 for six months at a time.) Next 
best thing is to buy a spare to replace the item when it reaches the end of its 
useful life.

Then there are alternate life styles, 
A. use 2 12BA6's. One in the BFO and one in VFO with a jumper in 3TF7.
B. Use a resistor for 3TF7
C. Use a 12 volt .3 amp tube for a 3TF7. (12BH7, 12BV7, 12BY7, 12DQ7)

Spend more time listening to the radio and less time wondering if you can 
afford to listen to the radio.

Cheers

Roger KC6TRU