Basically when I turn on the turntable the amplifier emits a feedback buzz/hum sound, that is constant as long as the turntable is on or until the volume is turned all the way down. At first I thought it was a mains issue but I moved the system around my home and to different outlets and it made no difference. It seems to be linked to the tone arm as every time I lift it the volume and pitch of the buzz/hum changes. Any ideas? I just moved and this is a new problem.