Okay gents. Adapted two-channel tube pre (schematic attached) to four channels and the tubes are way out of bias. A few key points:
1. The 6072 grids are at -5.2vdc
2. The voltage at 6072 pin 6 (1st gain stage) is about 13.5 vdc higher than it should be.
3. The 6072 pin 1 plate (2ns gain stage) is about 5.5vdc higher than it should be.
Would it be preferable to increase the plate resistance to lower the voltage or adjust the cathode resistors?
1. The 6072 grids are at -5.2vdc
2. The voltage at 6072 pin 6 (1st gain stage) is about 13.5 vdc higher than it should be.
3. The 6072 pin 1 plate (2ns gain stage) is about 5.5vdc higher than it should be.
Would it be preferable to increase the plate resistance to lower the voltage or adjust the cathode resistors?