Humming Problem with U-Mix Control Pro

[djwcswing]

I have a U-Mix Control Pro problem that just started.
I hear a humming sound in the background when I hook it up to my computer.
I know it has to be an issue with the U-Mix because when I hook up my Vestax VCI-300 to the same system I don't hear it!

Does anyone have an idea what's causing this problem?

I just got the new 27" iMaC with Retina display.

3.5 Ghz Intel Core i%
8GB of memory
Yosemite 10.10.1

[Jim B]

Sounds like you have a ground loop problem.

Try something like this in your setup

Ground loop Isolator.jpeg

[FigDJ]

Install a separate power supply for the controller and it will go away. instead of the controller drawing power from the usb port it will draw from the independent power supply. had the same problem and that took care of it. I guest too many things connected and drawings usb power.

[RoJeC]

My 2 cents.. I always use a powered hub (7 ports) for all other devices as my controller (which I connect direct).
Also the groundloop adapter (2 if you use 3/4) is a basic piece of equipment to eliminate hum (caused by power: 50Hz hum).
Each cost like €/$ 10 a piece.

[djwcswing]

Thanks for all your responses!

I think I'd like to first try a ground loop isolator.
Since it comes with RCA's on both sides, I assume I would connect the male RCA's into the output 1/2 of my U-Mix and then connect my RCA's from the ground loop isolator to my computer.

Is that right?

[RoJeC]

Not likely, but not impossible.

A groundloop adapter should be as close after a humming source as possible. In this case the U-Mix Control Pro. You do connect to the Output 1/2 but the other side should be connected to your mixer/speaker (cable).

If you return your output to your PC, pleases explain what/why you have this.

[djwcswing]

I practice djing on my iMac at home. I have a speaker system connected to my iMac (Logitech 2300 computer speakers)
When I'm playing a gig of course I would go from my Out 1/2 on the U-Mix to the mixer/speaker.
Sorry that I wasn't clear but what I wanted to know was when I'm at home on my iMac that I plug the groundloop adapter to my U-Mix Out 1/2 and then to my iMac since i normally go from there to my iMac without it.
I have to use an external sound card like the Behringer UA202 since the new iMacs don't have a line in like the older iMacs so the connection from the 1/2 of the U-Mix goes to the Behringer sound card which acts as my line in to my iMac and my headphone jack has the Logitech external speakers.

[RoJeC]

Ok, but why don't you send direct to logitechs.
You now created a longer channel with conversion steps that require all CPU power.
Alternative might be to use a connector to connect logitech to U-Mix Control Pro. Like RCA/mini-jack cable.

Still a groundloop adapter is a valuable piece of equipment to have for any DJ.

[djwcswing]

Jim B. Thank you. The ground loop isolator did the trick. The hum is gone!

[Jim B]

Nice one matey

I have to use one with my Hercules 4-Mx sometimes, depending where I play.