• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

12B4 vs. 12B4A

I may have a problem here, I have a quad of 12B4/As and I think pairing a 12B4 with a 12B4A will REALLY screw things up.
As I understand it the "A" version is a "slow start" version, the 'standard 12B4 is not. Paralleled on the outputs one will come up to temperature well before the other, drawing more current initially before the other....Bad idea? Smokin' bad idea?


_______________________________________________________Rick.........
 

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Eli.........I have a 3A heater, the four 12B4s' will take 2.4A of that....I have a 'spare' TX split-bobbin at 12VRMS that I want to run thru a 317 to run the 12XXX. I have a AX and an AT .....I'll assume the AX runs "too hot"....I don't know about the AT...............don't have a BH. If I can readily get a BH........Is it a drop-in or do I have to re-bias??

__________________________________________________________Rick.......