Hooked up Shiit Mani incorrectly

Another good reason why preamps should not include a phono stage.

Would be an easy mistake to make for those not paying careful attention.

@hickamore The engineered solution would be to use different phono-only connectors, caps that must be removed and are marked with warning statements, or other human factors safeguards.  In the nuclear industry caps are put over important buttons that should almost never be pushed.  Operators know they need to be certain whenever they flip up the caps.  Because of their design, they are referred to as "toilet seat covers".

But you have a very good point.

Jerry

A good place to ask these kinds of questions is the people who made the equipment.

Continued to troubleshoot the amps by disconnecting the inputs to the amp leaving the speakers connected then powering up the system the hum is no longer audible. Does this mean the amps are ok?