05-09-2010, 09:10 PM
Yes I have -16.5 volts on grid of the 42 all voltages are close to what they should be. I found the cause of the hum today the ground for both 77 were hooked to a tube socket rivet and had 20 mv of ac on them. I ran a ground wire to a good ground might have help distortion hard to tell at night. yesterday I unhooked wire from the if to grid of second detector and put a 4 meg resistor to ground and a .047 cap and used a radio to drive the audio amp and there was no distortion.