Weirdness with Moon Evolution 870A amp overheating on one channel with G2s

[BillK]

Here's a strange one:

Auditioning a Moon Evolution 870A amp with my Giya G2s. It sounded absolutely wonderful, but…

As soon as the amp was powered up, if the right speaker's mid/high cable was attached the amp would start to heat up like crazy. After only about two minutes the amp channel was over 15ºF warmer than ambient, and it eventually ended in the amp going into thermal shutdown for that channel after about twenty minutes. I actually burned myself on the amp when it happened the first time, a laser thermometer showing the other channel running at a nice 95ºF or so, but the right channel (that shut down) was at 205ºF!!

Why I don't understand this is if the cables are connected to any other amp I have handy (Levinson No. 334, Denon POA-8300 or Rotel RB-1552 Mark II) they have absolutely no issues driving the same channel.

Anyone have any ideas as to what's going on or why it doesn't happen with the left channel, or the right channel woofer, just the right mid/high, and why it doesn't occur with other amps?

I even tried connecting the right speaker's cable to the left channel of the amp, and then that channel went into thermal runaway, so it's definitely something about the right channel mid/high that it is having severe issues with.