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Hi there all...anyone have any ideas regarding the sudden intermittent high gain problem that showed up during a live recording of our first paid gig...of course!
I'll upload an audio clip of the pathology ASAP seeing as there is a 4-5 Meg limit on mp3 attachmnets for this site...
So I am an Electronics Tech and have performed preventatitve maintenenace on several JC120's in the past. Things like:
- the low value, high wattage bias resistors that drive the outputs are on stands and will go open circuit at the solder pads
- the single in line (SIP) pre-amp chips will rock back and forth and one of the legs will break between the top and bottom of the PCB (happened to me recently)
- the electrolytics capacitors will go low value as they dry out causing a loss of low frequency response
...BUT...never anything like this! Any ideas? Pattern recognition, anyone...thanks ever so much!
BTW: Having a hard time getting replacement JC120 parts - I've got a pile left over from my days a techie in music stores.
You know what I mean? Vintage amp = vintage owner
I'll upload an audio clip of the pathology ASAP seeing as there is a 4-5 Meg limit on mp3 attachmnets for this site...
So I am an Electronics Tech and have performed preventatitve maintenenace on several JC120's in the past. Things like:
- the low value, high wattage bias resistors that drive the outputs are on stands and will go open circuit at the solder pads
- the single in line (SIP) pre-amp chips will rock back and forth and one of the legs will break between the top and bottom of the PCB (happened to me recently)
- the electrolytics capacitors will go low value as they dry out causing a loss of low frequency response
...BUT...never anything like this! Any ideas? Pattern recognition, anyone...thanks ever so much!
BTW: Having a hard time getting replacement JC120 parts - I've got a pile left over from my days a techie in music stores.
You know what I mean? Vintage amp = vintage owner