Sorry if this post has been covered before but I've searched the archives and can't find any posts that answer my problem specifically. I've just bought a GT100 V2 and I'm beginning to experiment with setting up my patches. I'm using the 4CM into a fender supersonic 60 amp. I'm not using any of the GT's built in preamps so I need to program "amp control" into my patches to switch between the amps clean and overdrive channels. I followed the instructions from other posts and the whole setup was working beautifully, switching to the overdrive channel when I changed patches. Now when I plug the cable from the GTs amp control socket into the amp I lose all the effects from the GT100 and can only hear the clean signal coming through the amp. When I remove the jack from the back of the amp the effects reappear. Any suggestions/help would be appreciated. The GT is a fantastic unit but the lack of instructions on setting up patches etc is frustrating. Does anyone know of any books that been published that might be helpful in getting my head around the GT 100.