Here's a power supply schematic of my build. The circuit voltages are target voltages on the original 5F8A schematic, not my build.
My PT is a Mercury Magnetics FTHPT-P with a measured 47 VAC on the bias tap off the limiter and - 39 VDC to -42 VDC on the distal end of the 15K dropping resistor with no power tubes in. My bias supply is stock with the exception of a 47K + 10K-pot for bias adjustment (stock bias resistor is 56K) and at full resistance it measures 57.5K. I tacked a 2K2 dropping resistor between the bias tap and the bias diode to enable a -41 VDC measurement as per the schematic, but that's without power tubes in; perhaps that is unnecessary, the bias tap voltage will reduce with a full load? ~10%? I installed a LARMAR2 type PPIMV which measures about 210K across each side with the safety resistors in place (that's about as close as I could get to 220K). It's left full open for now.
When I put the GZ34 and preamp tubes in only, I get a dim limiter bulb and reasonably higher, unloaded voltages everywhere; off the limiter and no power tubes, the A-node voltage is 480 VDC! When I put in the power tubes on the limiter, the bulb is white hot and my bias tap AC voltage is incredibly low, like 21 VAC. My negative bias voltage is also low. I thought of lighting it up off the limiter to check the loaded voltages, but being as power tubes are a hot commodity, I'd love not to burn these to the ground!
![Mr. Green :mrgreen:](./images/smilies/icon_mrgreen.gif)
I do not detect any problems with the power tube socket wiring. I chose not to tie pins 1 and 8 because 5881 tubes do not have a pin #1 and I used two of them to support the two gridstopper resistors on the outer tubes. I will bypass the 2K2 resistor and check it again, later.