Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: frank57 on September 13, 2010, 12:58:45 pm
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To pick up on a thread I started here:
http://www.el34world.com/Forum/index.php?topic=9942.msg90619#msg90619
What Hiwatt did was:
The heaters go to pin4 on the first el 84 then to pin 5 on the 2nd el 84 tube.
Pin 9 from the preamp tubes go to pin 4 on the last el 84 tube.
Good or bad way?
The heaters are not the source of the hum which seems to be coming from v1 or 2.
The voltages are too high on the heaters though.
Would star grounding solve the problem if a tech can't find source of hum?
I think the hum quieted down when the an alligator clip was applied to the grid on v2 to ground.
Not sure. Possible clue?