AB165 mod help please!

[pompeiisneaks]

Look at the fender wiring diagram and it will all make sense.

I'm lost....

what is a 'wiring diagram'

~Phil

[sluckey]

I'm lost....

what is a 'wiring diagram'

It was a poor choice of words on my part. I should have said "layout diagram" (which is a wiring diagram). Not talking about schematic.

Pin 1 was used on ancient 6L6s with a metal case. Pin 1 was connected to the metal can and when connected to ground to act as a shield. Then someone invented glass and the metal 6L6s became extinct and pin 1 was no longer used/connected to anything. Smart folks at Fender decided to simplify their board layout and mounted the 1.5K grid stopper directly on the tube socket. The 1.5K was mounted between pin 1 and pin 5 on the AB165 as well as most other blackface amps. So, the correct voltage to measure on pin 1 of that amp is the negative bias of roughly -45vdc. Having 11 volts (either positive or negative) on pin 1 of that 6L6 in that amp will quickly destroy the output tubes.

So, look at the "layout diagram" and/or this pic and it will all make sense.

[pompeiisneaks]

Oh man I don't know why I didn't put 1 and 1 together there, that makes sense too.

sorry sometimes I'm denser than lead

~Phil