Surge protector

@rvpiano - Might consider doing 2 things, having whole home surge protection installed at your panel; and also getting non-sacrificial surge protection to plug the equipment into. I use ZeroSurge. I haven’t had any degradation for whatever reason(s) using one in both of my systems , and also with my main TV. And, they aren’t unreasonably expensive $290 for 8 outlets.  I had a Furman, don’t recall the model it cost $150 or so when I purchased it, it went wonky after a while and ruined a 55 inch tv

You absolutely should have one at your breaker box , if you want something very good on a dedicated circuit then go to VH audio great for audio .

if you just want one for the whole house still have installed at the. Breaker box 

Siemens make very good ones for under $250 on Amazon I have one 

plus the top model around $1k from VH Audio , for my dedicated Audio circuit 

and I believe it has power wave form correction ,I have to lookfor the paperwork 

it works excellent the sound sounds improved day or night .

Why don't you just take the amp boards out of the speakers and take them to be repaired? It's probably just a few screws and a couple connectors, and they probably weigh under 10 lbs, not that hard to do. 

Power conditioning your stereo is never a bad idea. But absolutely install a whole house surge protector in your panel. In addition to your stereo. Your TVs, refrigerators, stove, washer, dryer and everything else electric are all at risk, not only of failure but also fire. 

I have an Isotech unit for my amps and a few other devices.

I missed that post, @rvpiano  , I guess it must have worked okay.