My PRS amps have been dead quiet. In fact, they're by far the quietest amps I've ever owned. So something's amiss. Is it possible that you have an effects board that has a ground loop? If you have pedals, disconnect them and plug straight into the amp to eliminate that as a source of the problem. Also, turn the guitar volume down to zero to eliminate the pickups as a possible source of noise. Try a different cable, that often causes noise.
A power conditioner in an area that isn't inundated with bad AC power does nothing for noise unless it incorporates an isolation transformer and sometimes balanced power, and even then, that only matters if you're on, say, a circuit that has a noisy appliance like a refrigerator., or you're in an ultra-quiet setting like a studio where noise generated by proximity to AC power cords might cause induced hums at a very low level (and by that I mean, low enough that to hear it you have to put headphones on and crank the volume very high). And isolation transformer equipped, balanced power conditioners weigh at least 75 pounds and cost around $1000. Not the kind of thing most people want to take to gigs (and yes, I have one in my studio because I'm after the very lowest noise floor for recording, but I don't plug my guitar amp into it, I don't need to).
Conditioners might filter out some stray EMI/RFI, but are relatively useless with amps because they have large transformers that do their own filtering.
Don't waste your money on so-called "conditioners" unless you have a known problem with the AC putting out substantially less or more than 120V. In fact, some conditioners actually cause noise of their own, as my studio tech demonstrated with an oscilloscope a few years ago, and yes I had costly ones.
If you have a serious noise problem that isn't addressed by eliminating ground loops, orienting the guitar, or a cable, the first thing to check is the tubes. If the noise persists, the amp might need service.
