Ground loop noise/ extreme humming

[Mr-G]

Hi everybody,

I have the following problem:
When using my U-Mix Control Pro as a usb sound interface and I connect cinch out 1 & 2 with my regular amplifier, everything is working fine.
But since a couple of weeks I have active studio monitors with cinch, XLR and TRS connectors.
Every time I connect my U-Mix Control Pro via two separate cinch cables with my studio monitors, there is a very loud and disturbing humming, but only if I connect my laptop with my adapter. As long as my laptop is running on battery, there's no humming.
Do you have any ideas what I can do against this ground loop?
I have already tried out a ground loop isolator without any success.
I really want to use my studio monitors since the sound is clearer and more detailed. Thus I can do better mixes.
So any ideas are appreciated.


I also bought me an audio interface (roland quad capture) which works fine when connecting it to my studio monitors (using TRS). However, it doesn't offer the possibility to monitor/cue mixes.
The problem with Cross DJ is that you can only choose one sound card at a time. So please dear Cross engineers, it would be nice if I could use my roland audio interface only for the main out and my U-Mix Control Pro only for cueing.
Or is there already a possibility to use two different sound cards at the same time in Cross DJ?

Thanx in advance

Mr-G

[christiankoopmann]

Hey,

have you tested to take the batterie out of the notebook and run with main power? You could also test to switch the powercable from your local monitor boxes.
I mean that you rotate the power plug that the two pins are twisted (so you rotate the power plug 180°).
I know from my tour case with the power managment there I had also a grounding problem. It was solved by setting this.

regards
Christian

[Mr-G]

I'll give it a try.
Thank you!

[daniel clark]

hate suggesting this because it might not work due to different sc added together (via ASIO$ALL)might have inherent problems because of sc clocking which will have the effect of a delay in one of the sc,,asio4all is a workaround to add two sc together to a software instead of using a multi channel sc, i think that solving the ground loop/hum issue might be the better solution

[chrisbakeruk]

I've had enough of this too! I've sent back my unit and 3 times they have been faulty!

I've tried using a power hub, and unplugging everything so that it's just the controller on it! I've now ordered a powerlead to see if that fixes it, to be honest I'm fed up of mixvibes they've let me down over this one!

[christiankoopmann]

I've had enough of this too! I've sent back my unit and 3 times they have been faulty! I've tried using a power hub, and unplugging everything so that it's just the controller on it! I've now ordered a powerlead to see if that fixes it, to be honest I'm fed up of mixvibes they've let me down over this one!

Hey,
I can understand that you are not happy with this problem but this is not only MixVibes.
This Ground/Loop noises are an combination from soundcard, Laptop/Computer, Mixer and Amplifier.
With my first notebook a few years ago I had this problem too. Everytime I connected any USB Soundcard or also the build in to my PA System I got a humming sound.
The Problem: my notebook was not isolated correctly so there was a real Ground/Loop problem. I fixed it with an isolator system which was not as cheap as I thought but know no problems.
You can also get those problems with connecting Turntables or CD players or other systems to a mixer and the amplifier. This is normal with cheap power supplies or not isolated correctly.

So the main problem is that your connection notebook (where also the U-Mix Control Pro is connected to so it is the same system) and the amplifier is not isolated correctly (professional systems have ground loop switches at the back of the systems would check this too. (you can find many links on the internet about these problems and I had this too with some of my customers who rent my systems. http://www.installdr.com/TechDocs/999502.pdf)
[EDIT] the URL I also posted is not an buy option or advice or something else it is only a link to a technical document which also expose the situation and how you can solve it.[/EDIT]
regards
Christian