Just finished my FPIII build with octals for 6SN7's instead of 12AU7. Need some help please, the Voltage is low on two terminals ... I think.
This is not the extended version.
All the resistance checks were fine.
Voltage checks were fine except for two terminals. T15 and T31 are supposed to be 75 volts according to the manual. I have 12.6 volts at both terminals. Again, this is with 6SN7's instead of 12AU7s.
All other voltages were well within 5% or better per the manual.
I also tried a different pair of 6SN7 tubes.
And yes, I installed a .22 ohm resistor instead of the stock .62 ohm as per Docs thread.
I generally am not sure where to start troubleshooting anyway, but building with a different tube, I have even less idea where to start.
I thought/think it was strange that all other measurements, both resistance and voltage are fine ... maybe I zigged instead of zagged at one point.
I double and triple checked the pin-out changes between the two tubes which Grainger sent me (Thanks again Grainger). Everything seems ok there.
So either I missed something ... Or, Do 6SN7's just change the voltage at this terminal pair ? (but 12.6vdc compared to 75vdc? ... thats a big difference).
Thanks in advance for the help.
