Metropoulos Forum

I am wanting to use an auxiliary filament transformer for my tubes, but i am unable to find one that runs at 6.3v or 12.6v. the only ones i can find are for rectifier tubes running at 5v, so will there be any tonal or operational disadvantages of running my preamp/power tubes at a slightly lower voltage.

Yep. Get the heater supply voltage too low (and subsequently lower current draw) long term, and you risk cathode stripping, and an earlier death of the tubes. Couldn't calculate just how much shorter a life, and with old tubes it MAY be negligible anyway, but I still wouldn't risk it.

whats my next best option then?