I don't use cheater plugs. My method fixed the hums from a ground loop. Let me first establish a baseline. Some systems have two ground connections: one through the signal ground wire connection (interconnect) and the other through the ground pin in the AC plug. Most designers wire these two together and to the chassis. You can have a ground loop when you connect two components using an interconnect cable.
I don't use cheater plugs for two reasons: 1. I think they are usually not very good quality, and 2. I want the chassis wired to the AC ground for safety reasons. (I am paranoid...)
So you would need to decide where you want the ground point of your system to be. You want only one ground point in the entire sysetm. By ground point, I refer to the point that signal ground is connected to the AC ground. Most people think the ground point should be either the source or the preamp. I chose the preamp as the ground point because one of my sources does not use the ground pin of the AC plug.
If you choose the preamp as the ground point of the system, you may have two ground loops: one at the source and one at the amp. Typically, the hum is caused by the ground loop at the amp. So the next step is to get rid of the ground loop at the amp. Some amps have "float" switches for this purpose.
Before we go on, we need to make sure that the preamp is indeed the system ground point first. My understanding is that some TRL Dude preamps don't wire the signal ground to the AC ground. If you have this configuration, then your ground loop is from the source to the amp, which will produce even louder hums.
If you are still with me, now we can proceed to get rid of the ground loop at the amp. There are three points of interest at the amp: signal ground, AC ground, and the chassis. I would wire the AC ground to the chassis and then keep the signal ground float; i.e., not connect to chassis or AC ground.
I think my method is good and safe. I have heard some more "advanced" methods for grounding. But I think they are safety hazzards.
A remaining question is if I should get rid of the ground loops for systems that do not hum. I have a few gears to rotate and some combinations don't hum at all even they have ground loops. One school of thought is that if it ain't broke, don't fix it. The other school of thought is that even it does not hum when the sysetm is idle, it could produce ground noises when the system is not idle.
Thought?
