Well, I've gotten two responses from Johnson about the amp producing a hum.
Here is the email I sent him and the responses.
From me, "My FP10k has a hum that is coming through the speakers. It increases in volume if turn the gain knobs on the front up and also increases if use higher gain settings on the back of the amp.
I have trouble shot the amp with wires from my other FP10k that does not have a hum. It is the amp and not the cables."
First response, "When you turn on the FP10000Q, and input with signal, the front panel VPL is on. also the output signal is distorted, Right?
My response, "No nothing unusual with VPL or any distortion. Just a 60hz type of hum that will not go away with cable management. Everything else is fine other than the hum to my knowledge. Plays fine and all lights work correctly. I'm using all four channels."
His second response, "Please disconnect the input signal, only connectwith power cable and output cable. Then check that the problem is from amplifier or amplifier again?"
My response, "It doesnt make any sounds without input cables. All inputs produce a hum whether I use 1 input or all 4. I have 2 FP10ks and have changed input cables to eliminate them being faulty. It produces the hum with any input cable I have tried."
Is there some chance that the hum could go away if I used phoenix out of the mini to the xlr inputs of the amp even if I have tried cables that work fine with the other clone?