So, I got the schematic of the JVM now...

kannibul

kannibul

New member
And at first glance, the only difference in the tone stack is the slope resistor - 33K is Marshall's typical, 47K is what they have on OD2.

Talk about an easy mod...

The stuff around gain controls are a bit different as well, notably a bright cap being a bit bigger on OD2, and a leading from the gain control being smaller...
 
Also the "C83" mod, is nothing but lifting the cathode cap....which is what makes it "Marshall" sounding...

Normally, there is a 2.7K / .68uf cap on 1A from what I've seen. It's on V1B on this amp - however, it might be skipping V1A when not using the clean channel.

Still, I find it funny that people would suggest a mod that would "De-Marshall" the amp...lol - that 2.7K/.68uf combo is what gives it that Marshall roar, IMO...
 
There is some mod by clipping one resister or cap that is suppost to tame the gain some, cant remember the exact one. I never did it as I am happy enough with the thing stock.

Edit.............I see you already have it :D
 
Digital Jams":3c89er8j said:
There is some mod by clipping one resister or cap that is suppost to tame the gain some, cant remember the exact one. I never did it as I am happy enough with the thing stock.

Edit.............I see you already have it :D
Click to expand...


Yeah, I won't do that C83 mod for sure, but I might get a pair of alligator clips and a resistor and see if I can drop that 47K to close to a 33K and see if it's more in line with OD1.

Might - probably won't...I liked the amp just how it was when I had it before, just I thought it was overkill for me to use at home, and I got to where I just wanted to sell off all my guitar shit and go back to basics until I got re-inspired.
 
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