My joy was short lived. I soldered in the NFB, fired it back up to no sound again. This time I can see the 12AX7 tube is no longer lighting up. Went through and took voltages again. Here’s what I have now: B+: 381.8v DC B+1: 358.1v DC B+2: 357v DC 5Y3: Pin 4: 333.8v AC Pin 6: 334.4v AC Pin 8: 23.1v dc Pins 2->8: 5.35v AC 6V6: Pin 3: 368v DC Pin 4: 352v DC Pin 5: 54mV DC Pin 8: 23.14v DC Pin 2->7: 6.74v AC 12AX7: Pin 1: 348.2v DC Pin 2: 15mV DC Pin 3: 1mV DC Pin 6: 348.3v DC Pin 7: 20mV DC Pin 8: .5mV DC Pin 5->9: 6.73v AC Pin 4->9: 6.73v AC I’m sure you noticed the lack of drop in voltage between B+1 and B+2 and the jump in voltage at the plates on the 12AX7. Those were not the voltages I measured earlier today. They were a little higher than I expected, pin 1 was 308v DC, pin 6 was 311v DC, and B+2 was also 311v DC. But NOT 348v. WEIRD. I double checked the 22k voltage dropping resistor, but it still checks out with 21.7k ohm resistance. Sigh. Could I have shorted something when I soldered in the OT? I don’t relish pulling the board out, but i may have to. Unless someone out there has a better idea. This time I am dropping it for the evening and coming back with fresh eyes in the am.