Tube Amp Archive

you can ground the cathode THROUGH the secondary of the OT as a means of providing some local NFB as well. Without having a full description of the circuit (or schematic) it's hard to say exactly what's going on. This may be it because the OT seems to be the only way that the cathode was grounded. ...

Secondary. Color scheme is fairly normal, blue / brown on the primary and green / black/ yellow on the secondary.

Is there ever any reason to use a center tap on a secondary?

Hi, I just salvaged a single ended 6L6 amp from a 1960 reel to reel. The OT is a Schumacher but it has three wires on the secondary side yellow, green, black. The black wire was going to cathode of the 6L6. I've never seen three wires on the secondary side of a single ended OT - anyone know what tha...

Thanks - that makes sense. Maybe I'll drop the b+ to something under 400v with a zener and call it a day. I won't worry about trying to approach 315v.

Hi, I have a 64 6g2 Princeton (transition) and I'm trying to figure out what the B+ is supposed to be. My PT is 125P1A which is right for 6g2 but I am getting about 420v on the plates of the 6v6 (various nos 5y3's) which would match blackface specs. The 6g2 schematic says that I should have 319v on ...