Have you considered a prosound amp? Usually a better watts/dollar proposition than a plate amp, but may give up some convenience depending on install needs and perhaps some built in features like crossover or eq (depends on model of course) that you may or may not need. Behringer ep4000 is a very popular budget option.
Are you running the sub hard? Maybe a more powerful amp is the answer. I've had six of the PE/Keiga amps in gentle use for over five years without a problem. Two of the 250w "PA" full range plates and four of the old school 250w sub plates.
Yep, this is pretty much what I think I will do.... but HOLY COW.. I don't need 4000 watts!
I had 250 and with my sub it was great, even with my big room. It is rated at 600, so I would probably go 500 max or so.
I am looking for options like this.
Yup, outboard pro amps are the best. Its nice to have power to spare, that means the amp loafs, and runs cooler and sounds better because it is so easy to handle the load, just like a truck load of painters painting a house, more hands make easy work !!!!