paulraphael
Active Member
Not through the speakers ... the box itself started making a ~60 cycle, kind of ragged sounding hum. Loud enough to be audible over quiet music. I unplugged it and started it back up again, and the hum immediately came back ... and then vanished.
Background: it's a 20-year-old Unison Research Unico integrated amp, with a tube preamp (pair of 12au7s) and mosfet power section. It's been in storage for 9 years, and a month ago I set it up again after we moved into a house that has room for this stereo system. I've never had any trouble with it. My plan was to sell it, and replace with something more modern and sensible (and solid state), but I remembered that I really like the thing. It's just so pretty, and feels so good, and has this cool remote that's carved out of wood and that works through walls and has only 2 buttons: louder, quieter. So I'd be bummed if the thing died.
What could cause a whole amp to spontaneously hum, and then spontaneously stop? Could it be electrical interference in the mains? A capacitor starting to give up the ghost? A tube problem?
Background: it's a 20-year-old Unison Research Unico integrated amp, with a tube preamp (pair of 12au7s) and mosfet power section. It's been in storage for 9 years, and a month ago I set it up again after we moved into a house that has room for this stereo system. I've never had any trouble with it. My plan was to sell it, and replace with something more modern and sensible (and solid state), but I remembered that I really like the thing. It's just so pretty, and feels so good, and has this cool remote that's carved out of wood and that works through walls and has only 2 buttons: louder, quieter. So I'd be bummed if the thing died.
What could cause a whole amp to spontaneously hum, and then spontaneously stop? Could it be electrical interference in the mains? A capacitor starting to give up the ghost? A tube problem?