U-Mix 44 USB NOISE

[analytic]

Hi all -

I recently purchased DVS Ultimate and am happy with the performance of the software. However I've been having audio quality issues with the U-Mix 44 stemming from electrical noise propogating up the USB connection. I've done some pretty thorough troubleshooting, including grounding my turntables both to the mixer and to the interface. The noise is tolerable (but audible) when I'm using DVS alone, but if I switch to the phono inputs of my mixer I get a horrid warbling sound. This is not only annoying to listen to, but it interfere's with the proper functioning of the timecode when i stop the turntable platter. I've tried ASIO4All as well as the latest version of he U-Mix44 driver with no results. I've also tried using a direct box with an isolation circuit to remove the noise, with no luck. I've tried this on multiple computers and the problem occurs on all of them to varying degrees. The only way I can get the problem to disappear is by running DVS on my Asus n10j netbook using battery power.

What I have been able to notice is that even when I unplug all of the cables except for USB from the device and then monitor the signal using the meters in the vinyl configuration tab in DVS, there is still a visible noise signal, which is why I think this is a USB isolation problem with the U-Mix44.

Since I'm happy with the software I don't feel like trying to return the product; I'd rather try and find a hardware fix. I'd like to hear from others who have had experience with this sort of thing before I start buying stuff. Is there anything I've missed? I'm tempted to try and get a maya44 but it's bus-powered too, and I don't know if this is something I should expect to see with all bus-powered devices. If I buy an interface with a wall-wart power supply does USB still send power up the up the cable? I'm very pleased with the performance of the DVS software and if I can get these harware niggles under control I'll be in good shape...

[Blackbrook]

The only way I can get the problem to disappear is by running DVS on my Asus n10j netbook using battery power.

There are different power adapters and filters for noise extraction that exists onto the power lines. http://forum.mixvibes.com/viewtopic.php?f=259&t=16215&p=97084&hilit=power+adapter+power+adapter+noise#p97084

Scroll down to JimB's solution. This helped him out, maybe this is your solution, too

Greetings,

Steve

[analytic]

Thanks for the tip -

I'm reviewing the purchase of one of these isolators as we speak, but I've hit on something that seems to have helped. I ran a piece of speaker wire from the chassis of my computer (one of the case screws) over to the ground post on the audio interface. This seems to have knocked a solid 6-10db out of the noise, and though it has not entirely eliminated the problem, it makes the situation much more livable. I still get some nasty stuff through the headphones but it's mostly inaudible through my monitor speakers. Kind of a ghetto fix but better than I had before.

Cheers!

Taylor

[Support@MixVibes]

Ground issue for sure : with the netbook on battery no more noise.
So this has something to do with the AC.

[barren fell]

Is the computer connected to a network router/switch. If so unplug the network cable and listen. If the noise disappears you may also look for a ground loop caused by router's power supply and network wiring. Often the noise is caused by a combination of devices and accumulates.

The network cable issue is my "most favoured" issue when playing with various environments (always given that power wiring and audio wiring is done with care and is free of ground loops).

Good luck!

[analytic]

@barren fell -

Actually I'm not hooked into a network switch at the moment. In my work I've found that both video and network cables can cause ground loop issues in some instances and actually cure them in others. It all depends on your electrical environment and specific equipment, I suppose.

Thanks for the idea though, that's something I never would have thought of if you hadn't mentioned it! I'll keep that in mind before I add any new wires to my setup ...

Cheers!

[analytic]

Quick update:

I attached a $15 Scosche Eso34 Ground Loop Isolator to the outputs of my DJ mixer and the problem has disappeared. Isolators of this type are an inexpensive and useful thing to have in one's trick bag. They probably don't solve all ground loop problems, but they'll almost certainly come in handy in some situations, so if you don't already have one they're worth the money.

Cheers!