Hoffman Stout TMB Bias problem

[Bigjoedo]

Hello All,

       I built a Hoffman Stout TMB in a Hammond A0 43 chassis. I have a new CE Manufacturing Can cap 40uF 20uF 20uF 20uF. I have triple checked all the wiring, parts values and jumpers. The amp runs does not draw current through the current limiter. Voltages are very close to the readings on the Hoffman schematic. I hear some humming through the speaker. I have tested all the tubes and they are all good. All the grounds are good

      When I tried to check the EL84 (6BQ5) bias with Eurotubes Bias probe. The plate voltage is around 360 volts then the current starts to rise then the voltage and current are both gone. So I measured the output transformer from center tap to each plate and one half is about 185 Ohms the other half is 211 ohms. When I try to measure the voltage drop across each half of the output transformer the voltage drop never comes close to stabilizing.

      Amp is Cathode biased with 130ohm 10 watt resistor. I have tried adding resistors in series trying to stabilize things to no Avail. Thanks for any help

[mresistor]

Post the voltages you have on the EL84s.

[PRR]

> one half is about 185 Ohms the other half is 211 ohms.

This is normal. It's how a transformer is wound.

> then the voltage and current are both gone

"Gone"? Zero-zero? Went south for the winter? He's a real gone guy?

[Bigjoedo]

thanks for the replies:

    To clarify: The El84 Plate voltages are 355 Volts
Regarding Current, the current kept rising until it was more than the meter could read.
I increased the Biasing resistor to 180 ohms 10 watt and problem is solved

                                   Joe