I am still concerned we're not getting to the bottom of this, it seems a shame to have to give up and get a different amp when it may be a simple problem, or indeed no problem at all (just a bit much for a while and a particularly hot room etc).

Rob

Opened up my Behringer amp and gave it a good clean with some rags and the vacuum. (Touch Wood) It is working fine now, hope I am not tempting fate) but it is still running warm but seems more content, even when I took my mixer up to -6dB. I am only running 1 pair of speakers off this amp now (my 18" bins) so the punters still have music even if the amp does give up again.

Just out of curiosity, where do you set the amplifier's front panel attenuator?

Always @ 0 (full)

Hmmm - And what mixer do you use?

Soundcraft Spirit Live, 8 channel

What are the dip switches set to? I had an RMX2450 that would thermal at 4ohms due to sub 40hz signals and a big impedance dip at those frequencies. Don't forget that a box's nominal impedance isn't indicative of what the box's impedance might be at cetain frequencies. My box was actually closer to 2 than 4 in places, hence prenting a much harder load.

Try a 50hz filter, or at least switch the 30hz filter on if you've got it switched off. Also, double check the bridge mode switch isn't on.

I cut every thing below 30 hz on my graphic anyhow as my speakers won't drive down that low. Seems to be fine now anyhow. I gave it a tanking last night and it worked fine all night. Just needed a clean I think. Thanks to rob beech for mentioning this in the thread earlier.