Hum/Buz fro JC1

try cheater plugs on the amps to see if the hum thru the speakers stops

Houstoneef, what components do you have connected to your preamp? Try disconnecting one component at a time from the preamp and see if the buzz goes away. If it does that's your problem. To fix the problem get a ground eliminator and inset in circuit between the preamp and the IC connected to the problem component.

The pre is connected to PS audio Dac. I had disconnected the ground wire on the power cord of the pre but the problem is till there. Downunder and Seadogs1, can you explain to me how to do it.

Thanks

Houstonreef, have you tried what I recommended?