It could be, but I doubt it. Especially if it is getting hot. That most likely has nothing to do w/the hu. Sounds like you just got a bad apple
And the RF amps are really nice, but if I'm not mistaken, don't they want to be ran at 1 ohm? So far, Kicker is the only one I have found that makes their amps peak at 2 ohm. But I'd say there is someone else, I'm just not aware of them.
Alpine