If it were me, I would only run an amp like that designed for balanced input with a well matched balanced output device feeding it, like Atmasphere suggests.
If you can establish that a proper balanced output device works as it should, I would agree with Atmasphere that that is the way to go, assuming the ARC is working as it should mated to the right input. If it does not, then there is some defect at play that would have to be addressed, but hopefully that is not the case.
If you can establish that a proper balanced output device works as it should, I would agree with Atmasphere that that is the way to go, assuming the ARC is working as it should mated to the right input. If it does not, then there is some defect at play that would have to be addressed, but hopefully that is not the case.