I have an SVT4PRO that is about 2-3 years old (I can't remember) I am running a PR15H and a PR410H. I have never had a problem until recently. The last couple practices, the amp has cut out. I cuts out for short and long periods of time, during which I can hear the fan clicking on and off. The peak and limit lights still blink while there is no sounds coming out, so I know the head is still getting signal. I am not running at any higher power than I used to (actually a bit less gain and master than normal.) Any ideas or pointers? Also, on a side note: I play in a band with two treble hungry guitars. For the most volume with my current setup, would you recommend running the amp bridged and the cabs in series, or the amp in stereo with each power amp dedicated to a speaker?