Usb isolator

#1

This isn’t really for my mod duo, but I have an alesis multimix that I use as a usb sound card to record the output from my duo and recently I’ve started getting a high pitched ground loop whine. There’s a few usb isolators for sale on amazon but it gets really expensive if you look at higher speed versions, not that I need the high speed version but some say the low speed versions don’t work with focusrite gear and I don’t want to rule out future purchases.

For now I’ve plugged in a usb extender cable and it’s mostly got rid of the problem in the volume range I normally use, but returns if I crank the volume on the mixer, so I’m just wondering if I’ll get better results with an isolator and if anyone can recommend one.

#2

Before you do that, try lifting the ground on the power for the mixer with one of those 3->2 prong power adapters… Assuming you’re in a country that uses Edison plugs, i.e. The USA.
I have some cheap stereo Behringer active DI boxes that sound completely excellent. Ground lift switches solve all kinds of issues AND it’s a more flexible/pro solution. Annnnnnd it has input pad switches so I run my Eurorack nonsense into a pair and hit the -40dB pad for maximum signal to noise ratio.
USB ground lifts are sub-optimal solution and snipping a ground wire on a balanced cable is far cheaper.

#3

Unfortunately I’m in the UK, so there appears to be no easy fix on the power supply side. I figure that considering I appear to have discovered that it’s the usb at fault then the easiest thing to do is isolate that.