Hi, I am converting an old Bell Labs 2203C hi-fi amp and need some advice on the heater voltages. With 123V (my home wall voltage) in I am getting 7.3V on the heater windings. The circuit is the really old Fender 5B6 Bassman which uses V1=6SC7GT, V2=6SL7GT, and 5881's for V3&4. Will this harm the tubes? If so should I use a resistive divider to drop the voltage down?
Also I should mention that for some reason when the amp is plugged into the Variac( power switch on) the voltage is at 123V and as I turn the Variac up the voltage decreases to zero. I have checked the output of the Variac with my meter and it works correctly. Ie: from zero volts and up as you turn the dial.
- OT only.jpg (47.57 KiB) Viewed 517 times
I have attached the two schematics for reference. The Bell schematic is the model 2203B and I have a 2203C, but I belived the trannys are the same. Thanks for the help everyone.
Ivabiggun