Suggest you replace it with a single dual channel Crown. Be about the same price as the two amps you are replacing and way better. (https://www.amazon.com/dp/B01AD1R4A4?psc=1_).
As a professional musician, I appreciate that Crown stuff is the royalty of live sound power amps. Bulletproof. I have one hooked up to my home Bose stereo speakers and it’s flawless.
BTW, Behringer is not crap. I have had many pieces of their equipment over the years (headphone distribution amps, line mixers, small mini-mixers, etc.), and they work fine. Are they as good as the more expensive stuff they copy? No, but they are a great value and generally last a long time.
Bose speakers... You can stop there. Professional Musicians apparently have ruined their hearing. (Bose speakers are terrible.)
Thanks. The Polks require a common ground amp - are these of this type?
Walking through the jungle of Behringer products, old and new, is truly a dangerous trek. Some of their stuff is horribly bad, especially when it comes to anything involving an amplifier. Some of it is iffy, like rack gear that had good years and bad years depending on where they were made and when. Their new digital boards are not bad at all (gobbling up Midas really DID help). I’ve owned some and still do, but yeah, get a Crown amp.