Hi All,
I've got a weird one with my amp: After losing the left channel I noticed that the heater in the left 12AT7 wasn't happening. After tube rolling everything, including the rectifier and of course symptomatic tube, (which works fine in the middle and right sockets) nothing plugged into that socket gets warmed up - visibly or to touch,
Pulling all of the tubes and running a meter on the socket's heater pins shows 6.3V as expected and re-loading all of the tubes still shows 6.1V on the PCB where the heater cct wires terminate. (I'm running KT120's so expect that's why the 6.1V with tubes in).
A bit of background: When it started failing, a couple of times a jiggle of the back-left KT120 seemed to 'clear' the problem. That tube has since been rolled out (as a single swap) and no change to the fault.
Its so obvious why it's not working, but I can't find the actual cause...
Any suggestions where to go from here?
AB
I've got a weird one with my amp: After losing the left channel I noticed that the heater in the left 12AT7 wasn't happening. After tube rolling everything, including the rectifier and of course symptomatic tube, (which works fine in the middle and right sockets) nothing plugged into that socket gets warmed up - visibly or to touch,
Pulling all of the tubes and running a meter on the socket's heater pins shows 6.3V as expected and re-loading all of the tubes still shows 6.1V on the PCB where the heater cct wires terminate. (I'm running KT120's so expect that's why the 6.1V with tubes in).
A bit of background: When it started failing, a couple of times a jiggle of the back-left KT120 seemed to 'clear' the problem. That tube has since been rolled out (as a single swap) and no change to the fault.
Its so obvious why it's not working, but I can't find the actual cause...
Any suggestions where to go from here?
AB