Hey fellas, you've helped me fix this amp before - wondering if you'd like to go another round? I'm not an amp tech so I regret not being able to contribute more; just a player that likes to tinker!
This amp sounds so good, I hate to part ways, but I'm starting to have second thoughts. Amp Kat, among others suggested hard-wiring all the board connections in lieu of the crummy push-ons... that is starting to appeal!
Here's the chain of events: this amp has been really humming for the last year until last week when I kicked on the power after warm-up and purple sparks were jumping around in PT V7 or 8. Kick myself for not noting.
So I found R105 burnt.. Ordered a pack of spec resistors and replaced. warm-up/power up sparks in 2 power tubes. R107 and R104 burnt.
Now... you would think I would have taken a moment of clarity to start testing .here. nope. replaced those resistors, same power up, same purple sparks in V7, blown R107.
Moment of clarity has arrived. I remember Enzo saying something about pulling PT's with lights off and check for arcing, then measuring B+ voltages. Pin 4 is obvious B+, what is normal on what pins?
Amp is fitted with originals except power section are Svetlana (winged C). Would like to go to full set JJ's, but was wondering how to figure out if a bad tube(s) are causing the trouble, or something else is causing the pretty light show.
Also, something weird: none of the replacement resistors are blowing- just moving down the line of originals. well the last original just blew- still not feeling lucky!
I'm running out of resistors, so I thought better to ask somebody that can point me in the right direction.
Any help with thanks!
This amp sounds so good, I hate to part ways, but I'm starting to have second thoughts. Amp Kat, among others suggested hard-wiring all the board connections in lieu of the crummy push-ons... that is starting to appeal!
Here's the chain of events: this amp has been really humming for the last year until last week when I kicked on the power after warm-up and purple sparks were jumping around in PT V7 or 8. Kick myself for not noting.
So I found R105 burnt.. Ordered a pack of spec resistors and replaced. warm-up/power up sparks in 2 power tubes. R107 and R104 burnt.
Now... you would think I would have taken a moment of clarity to start testing .here. nope. replaced those resistors, same power up, same purple sparks in V7, blown R107.
Moment of clarity has arrived. I remember Enzo saying something about pulling PT's with lights off and check for arcing, then measuring B+ voltages. Pin 4 is obvious B+, what is normal on what pins?
Amp is fitted with originals except power section are Svetlana (winged C). Would like to go to full set JJ's, but was wondering how to figure out if a bad tube(s) are causing the trouble, or something else is causing the pretty light show.
Also, something weird: none of the replacement resistors are blowing- just moving down the line of originals. well the last original just blew- still not feeling lucky!
I'm running out of resistors, so I thought better to ask somebody that can point me in the right direction.
Any help with thanks!
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