Usb isolator

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.

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.

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.