I got myself a Marshall 4140 Club & Country Combo Amp that had quite a few mods done to it. A Presence knob was added, a half power switch, a footswitch jack added (I like that mod), a master volume was added to the lead channel etc. Most of the mods don't seem to affect the tone of the amp but I would like to know what is going on. My tech had my amp for 4 months. When I finally got it back, all he had done was re-tube and bias the amp. He claims the mods are so complicated that to remove them would cost a fortune. He also says that whoever did the work did a great job. He says extra gain stages were added and legs were just clipped off etc. Anyway I guess my question is this: Is my tech blowing smoke up my ass or can an amp be modded such that to restore it would be to ruin the amp? Does anyone know of a tech I can send the amp to who can at least tell me what mods were done so I have a clue as to what is going on?