When I had that problem (discussed in this thread) I called outlaw and spoke with Steve and then Scott.
Scott said to send it back for exchange. I told him thanks, but the amp is fine (I decided fine because dead quiet otherwise with no inputs)...and I tried the cheater.

My system runs dead quiet, except when my wind-turbine is really cooking (generating power and feeding grid). Some of our digital clocks also speed up, so I'll have to accept this. Only occurs when generating in excess of 10 kW/hr, which is usually at around 150 RPM and wind speeds in excess of 20 mph at 120' above ground. Actually I wrote about this, but I'll ask for ideas on filtration in another post.
Ideas appreciated.

Don't send it back. Try balancing some channels.