Bubbling noise / feedback when hooking up PX-5S USB

[Brunner]

I just purchased the Focusrite Scarlett 2i4 audio interface and I hook it up to my laptop.  It's connected using a USB cable.  My laptop is running Windows 8.1 and the Sound is configured as follows: Line Out (Playback) -> 2-Scarlett 2i4 USB; Line In (Recording) -> 2-Scarlett 2i4 USB. 

 

I hook up my PX-5S' line outs to the audio interface's line inputs and I can record/play without issues using Ableton Lite DAW.  However, as soon I hook up the USB connection from the laptop to the PX-5S, there is a bubbling noise (like a distant motorboat/motorcycle).  I replaced the USB cables but the noise does not go away.

 

I need the USB connection to the PX-5S for the Data Editor so I can edit my tones.  Any feedback, suggestions or comments are much appreciated.

[Mike Martin]

You have a USB Ground Loop. I'll bet that if you unplug your laptop from the wall letting it run on batteries the noise will go away. Of course that is only a temporary solution. If you Google "USB Audio Ground Loop" you'll find hundreds of people that have the exact same issue with all kinds of products. This issue isn't specific to your audio interface or Casio. The answers primarily involve USB ground loop isolators or other solutions which break the loop.

[B. J. Love]

Here's a discussion of the problem and a few alternative solutions in an earlier thread: http://www.casiomusicforums.com/index.php?/topic/6351-usb-audio-ouput-ground-noise/

[Brunner]

UPDATE: I got a couple of MIDI cables and connected the PX-5S to the audio interface - solved the problem.  Thank you for the feedback.