JCM 800 4104 - Advice.

[Kapo_Polenton]

It’s taking frequencies from the tone stack to ground, bypassing the resistance of the pot. Which frequencies I don’t know since we don’t know the value.

Actually an interesting concept. Maybe it’s a mid cut mod.

Yes, all the 800 combos had this. Mine is an 82 and it too had this on the mid pot. Just cut one side. to lift it. It was supposed to make the combo less mid focused with the G1265 apparently. So it will be a tad smoother or appear to have less bite in the mids. So they say anyway. Mine made a difference. But I like bite.

That's a nice clean amp though even with it's minor mods. Mine has been butchered up with some burned circuit board and a few chassis holes for mods. But seeing as I screwed around with it, can't blame anyone but me. It still sounds great now that it is stock