Audio Technica AT LP 120 noise issue
I will start with the setup: Audio Technica turntable connected to Marantz PM 7001 to the phono input. The switch of the turntable is set to Phono". Everything works fine in this setup.
After I connect a CD player in the CD Player section of the amp (with RCA stereo connector also) or any other device to any of the RCA stereo inputs of the amplifier) I get a continuous noise in the speakers only when I switch the amp to the Phono input. The noise audible even at low volumes.
I suppose that is a noise generated by a ground loop rather that EMI/RFI. I did the following:
- I tried different position of the turntable relative to the amplifier/speakers and other sources of interference but nothing happened. The noise persist with the turntable unplugged from the mains (the CD player has to be plugged in the power socket but not power on). The noise exist only on the Phono input and not on the other sources connected to the amplifier.
- I also tried different RCA cables;
- I used the same power outlet for all interconnected devices (same grounding for all), nothing happened. All the power outlets use have grounding.
- Tried to use different positions of the power plugs relative to the power outlet in case some devices are using the Neutral as ground (CD player does not have grounding and the Turntable uses the RCA cable)
-I tried different settings with an additional grounding wire connected to the amplifier ground screw (near the phono inputs) and to the turntable platter/motor or turntable arm or CD metal case. Nothing happened.
The only solution I have so far is to unplug the RCA connectors from the CD player every time I want to use the Turntable.
Please help me with some advice. Is that anything that I can try?