@hagtech I held the phono stage in the air, about 4 feet away from everything, didn’t help. Could be that I have no true ground, as you suggest. Interesting that the hum goes away when I touch the RCA tip from the preamp audio to a ground.
@cleeds The hum exists even with the cartridge not connected to the system, and issue has been there for a long time.
@cleeds The hum exists even with the cartridge not connected to the system, and issue has been there for a long time.