I PICK UP FM STATIONS WHEN USING THE LOW NOISE SWITCH AND TWO TURNTABLES.
What is really happening is that you are probably close to and FM station, and the long interconnects act as an antenna. Your amplifier is probably not protected from RF getting into it. Somewhere inside it is detecting the RF's sound. The fix normally is to solder small value capacitors worth only cents to the phono input jacks. however, such problems can sometimes be madening.
You should normally connect the two turntable ground wires to the switch and another lead from the switch to the amplifier's chassis. Double check that you have done so.
The only suggestions we can make are:
* try moving or reorienting the equipment.
* try reversing line cord polarities, i.e., pull out AC plug and rotate them before reinsertion.
* try grounding the two turntables to the amplifier, and yes, the switch also.
* try coiling any long cables into a smaller area, or get shorter cables.
You can send it back along with return shipping of $5.50, and we could try modifying the unit to reduce the RF pickup. However, be aware that the long cables and ground leads might negate those efforts.