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Vintage threads from the first ten years

previous: David Manson All I can figure now is to tinker a... -- 10/6/1999 6:59 AM

Re: Amp HUMMMMM!!!

10/7/1999 3:49 AM
jeff	Re: Amp HUMMMMM!!! DAve, isolate the hum if you can . pull the last 9 pin 12AX7/type tube (phase invertor/driver tube)then power up and see if hum is absent. Move towards the first input/preamp tube . power off,pull the tube, power on etc.. also carefully check the integrity of the input jack for all connections and that it is properly and tightly mounted on the chassis. you should not have dc voltage on the grid pins (2 & 7)

10/7/1999 3:49 AM

jeff

Re: Amp HUMMMMM!!!

DAve,
isolate the hum if you can . pull the last 9 pin
12AX7/type tube (phase invertor/driver tube)then power up
and see if hum is absent. Move towards the first input/preamp tube . power off,pull the tube, power on etc..
also carefully check the integrity of the input jack for all connections and that it is properly and tightly mounted on
the chassis. you should not have dc voltage on the grid pins (2 & 7)

Replies:

Ken Gilbert q{you should not have dc voltage on... -- 10/7/1999 1:01 PM