audio with realistic timbre


Having fun with 1920's triodes..
April 6th, 2015 16:54
Late 1920's the first indirectly heated triodes were developed. Primarily to replace directly heated triodes, hence the 4-prong base and side/top-pins for filaments.
Cardon AC 373 triode
The Cardon AC 373..
Kellogg 401 triode
And the Kellogg 401..

Running both 3 Volts at 1 Amp for the filament and a B+ of 90 Volts at 4mA.They make for a very nice sound!