Likely needs recapped and if I had to guess it’s the amp. Try to isolate which component it is if you can. I think if it’s the amp and if you leave the preamp off the amps going to hum regardless. Both should be easy to work on so hopefully you have a good local tech that can help you or call the new owners of Aragon to see if they can help. Indy Audio.
http://www.aragonav.com/
http://www.aragonav.com/