It may be simpler to just plug all the equipment into the same wall outlets, and then you would have a better common ground. Then you could add your DIY supplemental ground after that and not worry about adding a ground loop or causing a safety hazard. If you really want to hotrod your setup plug everything into a good power conditioner and that will give you a much superior common ground plus power conditioning.
DIY Active Ground Box
I recently received a custom cable that has three loop-ground spades that are linked to the cable's shield. The cable was originally designed for phonograph use, but my customized version is being used in a digital to analog function. The manufacturer left the loop-spades in. The manufacturer said I could just use electric tape to "cap them off." The ground cables are not 100% necessary in this application. However, they are an exposed conductor. I know that I can enhance their performance by treating them as a floating shield by using an active ground.
I was thinking it would be cheaper and more practical to make my own. Does anyone have experience doing this? If so, can you share your design ideas?
The concept I have seen and want to build on, is making a wooden box that is coated internally with copper plates. Then use an IEC C14 socket to attach the ground lead to the copper plates via a solid copper cable. Then create a simple plug using a NEMA 1-15 connector where only the ground lead is connected.
Then insert banana plug sockets that also attach to the copper plates via a copper cable. Then connect the spades to the banana plug outlets.
Once this contraption is plugged into the wall socket, it should effectively attach to the house's ground.
Thoughts?