Hi
i registered here, i thought you could help me out. I am from germany, so my english could be a little bit weird.
MY JMP1 OD2 Channel has issues since today. If i turn up the gain theres a loud pheep, screaming noise to hear, but on gain stage 20, 15, 10, 5, 0 there is no pheeping noise. In Area 10-15 the noise changes little bit in the tone height..
There must be a logical issue, but i cant detect it on my own.
Whats wrong here? That amp is modded after the french jmp1 article.
Thank you .
i registered here, i thought you could help me out. I am from germany, so my english could be a little bit weird.
MY JMP1 OD2 Channel has issues since today. If i turn up the gain theres a loud pheep, screaming noise to hear, but on gain stage 20, 15, 10, 5, 0 there is no pheeping noise. In Area 10-15 the noise changes little bit in the tone height..
There must be a logical issue, but i cant detect it on my own.
Whats wrong here? That amp is modded after the french jmp1 article.
Thank you .
I think you mean a "beep" or "squeal" noise.
Does it happen with a guitar plugged in?
Re test JMP1 with a shorted nplug in the input, does it still squeal?
If not, but squeals with a guitar, you might have a bad guitar cable or your guitar feeds back with higher gain.
Test and post results.
IF it feeds back/squeals/oscillates on its own, no guitar involved, then it will be difficult for you to repair it on your own, it´s a very complex preamp, midi controlled, all potentiometers are replaced by variable gain integrated circuits ... not easy.
Does it happen with a guitar plugged in?
Re test JMP1 with a shorted nplug in the input, does it still squeal?
If not, but squeals with a guitar, you might have a bad guitar cable or your guitar feeds back with higher gain.
Test and post results.
IF it feeds back/squeals/oscillates on its own, no guitar involved, then it will be difficult for you to repair it on your own, it´s a very complex preamp, midi controlled, all potentiometers are replaced by variable gain integrated circuits ... not easy.
Yes it does squeal by itself, without anything plugged in. If i tick on some resistors, tone changes. But there are so many... If i blow the valve warm, the tone changes. Tube change brought nothing.
I even thought of grounding issues, but even with the board deinstalled on the table, it squeals. But not on Gain stages 0, 5, 10, 15, 20- there is no tone on this stages.
I even thought of grounding issues, but even with the board deinstalled on the table, it squeals. But not on Gain stages 0, 5, 10, 15, 20- there is no tone on this stages.
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