Quote:
Originally Posted by miniman82
Interestingly, one of the filament windings on the B+ PTX is 6.6v center tapped... I guess I could always run 5U4's at a volt more than normal, but perhaps 3DG4's would be more appropriate?.
|
Since the early vacuum tube TV days, the ubiquitous 5U4 has gone from the lowest-priced commonly-replaced bottle to being quite dear today. I'd say running those babies at 6.3 volts could get expensive in a hurry. I wonder if they make 1.3 volt 3 amp pilot lights?
On a twin-tube "B" supply, if one tube opens a filament, the other tube promptly melts before the user notices and can shut the system off. On 5U4's this problem seemed to be worse with the fat G's and first generation GT's than with the GB's
If the filaments were wired in series, this would protect the second tube.
Are the tubes in the picture from the organ? If not, any idea what tubes the organ used?