Jeff, I have a 1501a that was sent back to Jolida because the left channel failed. When I got the amp back it had a similar hum, even though none was there before. Much to my dismay, it had to go back. I was pretty frustrated as I was without my amp for a month.
Jolida was great. They sent me a new one and pick up shipping for the old because it left their repair center with the hum
Chip
Jolida was great. They sent me a new one and pick up shipping for the old because it left their repair center with the hum
Chip