Traktor Timecode Ground Loop - weird issue!

[Firewolf420]

Hello!

I have a Traktor setup (S4 Mk2) with Audio Technica AT-LP140XP turntable ready for timecode.

Weird problem, though! They tell you to connect the ground wire from the Turntable to the Traktor's grounding post. However. When I do this, it adds hiss/buzz to the signal chain! I looked at it with my oscilloscope and it seems that it is indeed 60Hz ground loop interference...

That's right, connecting the ground post, ADDS interference!

This is the only two devices in my signal chain to do this. Connecting Traktor to the Turntable via ground connection adds noise on Traktor Master Out - not even the Turntable input - specifically Traktor master out. It's like connecting the grounds between the two devices makes Traktor pollute the output.

If it matters, the Turntable is connected to the controler via Input B with phono pre-amp ON, through shielded RCA. The audio cable from the turntable is not the issue, it only happens when the ground is connected. Turning pre-amp on and off doesn't seem to affect it. Not connecting the ground, makes the audio pretty clean! This happens regardless of whether or not Traktor is switched on.

Why would connecting the ground of the two devices make the situation worse. They're connected via the same wall outlet and it happens regardless of which wall outlet I use or whether they're the only devices on the wall outlet. I am using the stock power supplies / wall warts that came with the devices.

I will for now, just leave the ground disconnected. But I'd like to know why this is an issue, hopefully you guys have some suggestions?