Does the amp hm without any other component pluged into it? You may have to try the amp in anoter system to see if that if it still has a hum. In my experience the hum is either a grounding issue or a cap that is going bad. Remembr that the caps are 20+ years old. If you live in the New Jersey area I know a good tech.
Happy Listening.
BTW the mods take the amp to a different level and you can do them yourself.
Happy Listening.
BTW the mods take the amp to a different level and you can do them yourself.