Manual is at https://www.hifiengine.com/manual_library/apt-corporation.shtml
Does hum only come when channel cuts out? That sounds like cable.
If hum in both channels, the turntable to pre-amp separate ground wire is suspect as others wrote. This ground is a separate wire, not the shield of the RCA interconnects. Post on back of pre-amp to ground on turntable.
What is Holman's current company?
Does hum only come when channel cuts out? That sounds like cable.
If hum in both channels, the turntable to pre-amp separate ground wire is suspect as others wrote. This ground is a separate wire, not the shield of the RCA interconnects. Post on back of pre-amp to ground on turntable.
What is Holman's current company?