Uneven/unbalanced heater voltage

[Duncan]

Hey guys,

I’m in the last stages of getting a new build up and running (sort of a unique take on a jcm800 circuit) and I am noticing on my heaters, I’m getting about 3.4 VAC on one side and about 6.5 VAC on the other.

Has anyone seen this before?

From what I can tell, everything is wired correctly, and I am at a loss.

Thanks in advance!

[shooter]

are you using resistors to make a CT with the filament supply?
if so, verify both R's are the same value----with a meter

[Duncan]

are you using resistors to make a CT with the filament supply?
if so, verify both R's are the same value----with a meter

Nope. The PT has a centre tap that I’m currently running to ground.

[sluckey]

To correctly measure heater voltage measure from pin to pin on the tube socket, not from pin to ground. IOW, one probe on pin 2, the other probe on pin 7. Or, one probe on pin 4/5 and the other probe on pin 9.

[Duncan]

To correctly measure heater voltage measure from pin to pin on the tube socket, not from pin to ground. IOW, one probe on pin 2, the other probe on pin 7. Or, one probe on pin 4/5 and the other probe on pin 9.

Measured pin to pin, got about 3.5 VAC

[pdf64]

Maybe the CT has somehow been mixed up with a winding end?

[Duncan]

Maybe the CT has somehow been mixed up with a winding end?

Well shoot. I just reviewed the wiring diagram for the transformer and that’s exactly what I did. Turns out the winding leads are black and orange, and the CT is brown.

Facepalm central.

Thanks!!