Hum/Buz fro JC1

Does any JC1'owners have this problem? Any recommendation and input to fix this problem is appreciated.

Downunder, i did the same thing with 3 prong female by disconnect the ground wire so which means that there is no ground feeding the amp.
it could also be that your rca jacks from preamp to amp are not seated all the way in the amplifier input jacks. If you are using locking type rca connectors, then you may want to make sure they're pushed all the way in. Some input jacks make it seem like they're in all the way, but in reality there's still room.
Also, try connecting your cd player to the amp(but don't hit play) and see if that causes the same buzz as the preamp does. If not, your preamp is causing your problems.
The best info I have seen about cheater plugs is not to use them. The shock from an ungrounded chassis can be lethal. If the interconnects are well made and properly seated, the next step would be to use a good quality power strip and plug all the units into it. Generally that should take care of the problem unless it is a real design flaw in one of the system items. Good luck.