Replacement amp for subwoofer

Not sure what went wrong with the old a/d/s amp in the subwoofer.  It's distorting at any volume level over a whisper.  Nothing visually wrong with the capacitors or any other components on the amp boards.  I hooked up the two 10" speakers in the sub to my Schitt Vidar and drove with Spotify from my iPhone and they worked great, so it's the amp.
Thanks for all the suggestions!

+1 millercarbon

   I'm the Tim that millercabon mentioned in his post suggesting the Dayton SA1000 sub amp.  I've been using this 1K watt class AB amp to power my 4 Audio Kinesis subs for over 5 years now.  I've had in on 24/7 since I got it and it's still working flawlessly.  Highly recommended.

Tim

Stretch the budget a bit and you could get the Dayton SA1000 which is one mighty fine sub amp and the one I use in my DBA. https://www.parts-express.com/dayton-audio-sa1000-subwoofer-amplifier-rack-mountable--300-811I'm using 2 but you really only need one of these to run four subs. That's what Tim does with his and what Duke sells with his Swarm subwoofer system.

+ One on the Parts Express. All kinds of goodies, and options if they are out of stock. 

Regards

Details of the ailing sub?

Good question.
I don't know. I usually DIY amps. It is very good for me, with a low cost and good effect.
I design a PCB board and send it to 
http://www.nextpcb.com/?code=James 
Only $7 I got my PCB assembled amps board for 5 pcs.

How about this?
https://www.parts-express.com/dayton-audio-apa150-150w-power-amplifier--300-812