Connecting the ground wire makes music less lively

Hi Pradeep,
You are using a SUT with a low gain MM stage, that should not cause a hum IMO. In my system when I use a lower gain stage the hum is gone. The hum is only there when I use the highest gain on the phono. Unfortunately my MC cart needs the highest gain so I have no choice.

Do you hear the hum with both your turntables ?

Are the phono cables routed near any power cords, power supplies, or components that may be inducing hum in them? Did anything change in the system or its physical setup around the time the problem appeared?

Also, my suspicion would be that if connecting the ground wire makes the system sound "less lively," that having it not connected is somehow compensating for some other issue. If you haven't already tried this, see how the system sounds with the wire connected and with the resistive loading changed to a much higher value than the 100 ohms you have been using. The relatively heavy 100 ohm load may be adversely affecting dynamics. (I note, btw, that 100 ohms is the **minimum** load impedance recommended for the AT-ART9).

Regards,
-- Al

Does the phono preamp have hum in the highest gain setting when there are no interconnect cables connected from the tone arm? If it does the arm and cartridge may be off the hook.

The loading resistors need only be used if your preamp is susceptible to Radio Frequency Interference (RFI). Ignore what the manufacturer recommends- if their preamp was susceptible then they will have a recommendation. Otherwise the stock 47K is sufficient.

I would certainly start by grounding the wire and removing the loading resistors- see how that works for you.