What filament voltages should you see on pins 4 and 5 of the tube socket? The schematic is incomplete. I am seeing -12VDC on pin 5 with the tube out and -5VDC on pin 5 with the tube in. 0VDC on pin 4 (looks to be tied to ground). The complaint is very weak audio. I have installed a new 12AX7 with no change. I do have my hi and low voltage rails, so the power supply looks to be working.
What filament voltages should you see on pins 4 and 5 of the tube socket? The schematic is incomplete. I am seeing -12VDC on pin 5 with the tube out and -5VDC on pin 5 with the tube in. 0VDC on pin 4 (looks to be tied to ground). The complaint is very weak audio. I have installed a new 12AX7 with no change. I do have my hi and low voltage rails, so the power supply looks to be working.
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