Tubes can be imperfect beasts no matter the duration of use on them. It sounds like a bad tube, which will get worse. I would also like to add that I had nordost SPM interconnects running from my power amp to my subwoofer and I was hearing a tremendous amount of hum. I removed the SPM's and connected a pair of audioquest subwoofer cables from the power amp to the subwoofer and it is dead quiet, so through my own personal experience, cables can make a difference! Good luck, Hope you find a solution for your situation.
Hum in ARC Ref 3 not on 0 but 1-103 light buzz
I'm suddenly experiencing a strange phenomena with my ARC Ref 3 (250 hrs on the tubes). On the 0 setting of the volume "dead quiet" with 1-103 a constant sound like the sea whispering noticable on 2 meters from the speakers. Any idea where this comes from? It is from both the two speakers. Tube problem?
Thanks in advance!
Thanks in advance!