Are these value correct?

[zorro]

My 6V6's cathode currents are 44ma & 47ma in my 5E3.
Isn't this a little high?
405 volts at the plate
360 after 1st resister
274 after 2nd resister
between pin 5 and 8 on both 6V6's = 18.7 volts
The amp plays fine. I don't want to kill my tubes.

[Bruce / Mission Amps]

My 6V6's cathode currents are 44ma & 47ma in my 5E3.
Isn't this a little high?
405 volts at the plate
360 after 1st resister
274 after 2nd resister
between pin 5 and 8 on both 6V6's = 18.7 volts
The amp plays fine. I don't want to kill my tubes.

I don't know how your cathode voltage is so low but the whole amp is running about 40vdc high.
Normal B+ on a 5E3 is around 355vdc to 370vdc.
What cathode resistor are you using... with the correct plate voltages, it should be around 20 to 23vdc.
If you have a std 250ohm resistor, then your cathode voltage would have to be 22.75vdc to pull 91ma of current.

[zorro]

250 ohm

I do have a 250 ohm 5 watt resister going to pin 8.
I do get 21.4volts right across the 250 ohm resister, but not across pins 5 & 8. I still read 18.7 volts. I do not see where I am getting that voltage drop difference. Looking from ground, I am getting zero volts at pin 5, then zero after the 1.5k and zero at the 220k junction.
Do you suggest I first concentrate on lowering my B+ or should I be also concerned that the voltage across the 250 ohm is not the same as between pins 5 & 8.
What is the best way to lower the B+ without producing extra heat.

[MWJB]

I'm not quite sure why you are measuring the voltage from pins 5-8 on the 6V6s, or why you are looking for DC on the grids of the 6V6s (pin 5)? Pin 8 should be measured to ground. You could measure pin 3 or 4 to pin 8, instead of ground, for corrected voltages (voltages that the tube actually sees).

According to your figures you 6V6s (14W) are dissipatiing 18W.

Assuming that you are already using an NOS 5Y3 rectifier, the simplest way to drop 30-40v B+ is to install a zener diode between B+ centre tap & ground (assuming that your heater voltages are not also elevated beyond 7VAC). Mission Amps, Weber VST & Torres Engineering should all be able to help you with such a device.

Rebiasing colder, by using a larger value cathode resistor, will push up your plate voltages substantially, beyond the "normal" range for a 5E3.

[zorro]

I was reading somewhere, where they were referencing the voltages between pins 5 and 8. For some reason it seemed that there was a range that was considered normal, so I listed that voltage. The zener option sounds fine. Is the drop in B+ voltage proportional to the voltage drop across the zeners? I am assuming I could cascade some 5 volt 5 watt zeners on the center tap to acomplish this.
Thanks

[MWJB]

A fixed bias amp would have negative dc voltage on pin 5, so in that case you could measure pin 5 to pin 8 (ground).

Yes, the drop is proportional to the zener rating (or near enough), a stud mount 50W zener would do the whole drop in one go, it would mean drilling a mounting hole between the PT & OT (plenty of room).

[zorro]

I just put in some zeners into the center tap winding to get a feel of the effect. I had two, 6.8 volt 5 watt and two 5.1 volt 5 watt zeners. Well, it's almost on the money. I am getting 376 volts on the plate. It dropped from 405 volts and my 6V6's are pulling 36 ma and 38 ma. Now I will order a single 25 watt zener and mount it on the chassis.