[ARC5] 6SS7

[Robert Eleazer]

"I have a radio or two around here somewhere with *SS7 tubes where the *SK7 once lived. Heater requirements are different so don't stuff into a series string where 6SK7 lived. Plate dissipation is somewhat lower,
too. For an IF amp that is probably not an issue. 73, Bill  KU8H"

That's the really funny thing.  The 6SS7 has half the filament current of a 6SK7, and the set uses a mix of series and parallel filament circuits.  So it makes a difference which one you use.

It appears the early Detrola 438's use two 6V6's in the audio output - with some big resistors back there.  The slightly later BC-1206-A military versions use a 28D7, and the later BC-1206-B uses two 25L6's.

Makes me wonder if the 438 originally was designed for 12VDC for civilian applications.  I wonder if that would work.  I have run my ARC R-511 on 28VDC on both B+ and filaments, but have not heard of sets going lower than that. 

Other than the audio section the rest of the tubes seem to be the same except for the anomalous 6SS7. 

By the way, in case you ever wondered, 6V6's get Real Bright when you plug them into a circuit designed for 25L6's...  

Wayne