I used to have this problem with big Parasound amps, and the cheater plugs actually did cure the problem. Didn't have to ground any other components, either
Can I ground my preamp?
I have monoblocs each w/their own grounded cord and a preamp w/o a grounded cord. The problem is that I'm getting a slight ground hum from each amp. The amp manual says if this happens to use a cheater plug on the amps and to ground "at least one other component." Is it possible to ground my preamp, and if so how? Many thanks for any advice.