On Wednesday, August 8, 2012 1:55:28 PM UTC-7, Michael Terrell wrote:
PrecisionmachinisT wrote:



My old Triplet 630 seems to work just fine for this and since the "B" cell only needs replacement about once every 30 years......

It has two 'Batteries', B1 & B2.



B1 is 30 Volts (NEDA 210) which costs about $40 these days.

B2 is 1.5 Volts

The nomenclature has changed. Old-style radios had an A battery (like your D cell, 1.5V)
for the filaments, B battery (30V) suitable for biasing vacuum tube grids, and C battery
for the plate supply.

It was a real technological stretch when Motorola made a 6V automobile radio set...