I'm in no way agreeing with this, just posting what was said on caco.
"We have seen several cases where the dd-1 caused a similar problem with other amps. It is likely that it has some bad parts in the protect circuit. How it happens, I do not know, we just know how to repair it.Yours likely will be one of the $150-$250 range since it probably just has some bad parts in the protect circuit thanks to the DD-1."