USB Noise

I have my Behringer X18 Air digital mixer hooked up to my Macbook Pro via USB for backing tracks in Logic Pro X. It all works fine and the audio streams via the USB cable out to the mixer.

 

I also have a hardware synth (Roland JP-08) hooked up direct to the desk via 1/4 jacks. That all works fine and I can play the synth lines on top of the backing tracks for live work all on separate channel strips.

 

However, I need to introduce a second USB cable between my Macbook and the Roland JP-08 to send program change messages from Logic Pro X to the synth module to change the patches. This works fine (the patch changes from LPX to the sound module), but I then have a sort of warbled alien noise in the background when I connect the second USB cable. The noise does disappear when I remove the second USB between the Macbook and JP-08, but I need this to send the program change messages from LPX.

 

Any thoughts please?

Are you also using USB to power the JP? Do you hear the noise through the JP's headphone jack?

I have the JU-06 and I had a noise problem from the USB connection. If you search around the web you'll find others with this problem and the answer - that worked for me - is to open up the USB cable and cut one of the wires... hang on... I'll find the link... cutting the ground wire... ah... can't find the thread I followed... but it was really easy...

This starts with a good explanation...http://electro-music.com/forum/topic-16104.html

Sorry I can't find the nice easy instructions... have a search...