A heater wiring DOH! moment??

[maynardg]

Hello Folks. I am working on a new SE amp. Problems with the 6.3V heaters. I measure 3.2V at each pin (both socket and pin). Neither the 6SJ7's nor the KT88's heat up. What is my DOH??

Should I be grounding the CT or should it float?

 

[w5jag]

You didn't by chance use the 230V primary on a 230/115V dual primary transformer, did you?

I would think you would want the center tap grounded, but just disconnect your filament string from the transformer, ground the center tap, and see if that gives you the voltage you expect.

Win W5JAG

 

[maynardg]

I have the 5V rectifier and B+ I expect. The 6.3V heaters are CT and the CT is grounded.

I think perhaps I have a faulty heater supply. One lead reads 3.2V, the other .33V referenced to ground.

Darn.

 

[Zibi]

If the transformer is good, one of the filament wire is probably shorted to the ground.

 

[Alastair E]

Sounds to me like the centre-tap is wired out of phase, IF you measure 3.2V at each heater pin with the ct earthed.........

reverse one half of the 6.3V secondary heater winding, and all should be well....