I've just been through the harrowing experience of finding all the ground loops and other sources of noise when trying to use HD500 with computer and guitar amp simultaneously. I had to use a 3 prong to 2 prong adapter on a tube phono preamp (which of course the phono preamp doesn't like), disconnect the FM antenna coax that goes to other recievers in my house (and yes I have a coax isolator that solved a similar problem I had a long time ago, it didn't work in this case), disconnect audio connection from jam room/studio to another reciever in another room, and put my Profire 2626's power cord and a few other things on a power strip on an isolation transformer also with no third prong ground connection.
So if I completely change many things in my system, losing several aspects of functionality, I can actually reduce all the sources of hum and noise coming out of the guitar amp.
However, since every single other device I use has always been perfectly happy the way things are, the obvious solution is use a device to galvanically isolate the USB signal between the HD500 and computer.
There are several on the market, probably based on the same ADUM3160 or adum4160 chips. http://www.analog.co...lation/fca.html
I bought this, it has the adum3160 chip.
When the HD500 is plugged in through the USB isolator - ALL the different noises are gone! BUT - the driver won't load!! It sees that it is an HD500 but will not load the driver. I tried every conceivable combination of cables, with/without USB hub before/after the isolator, TWO completely different computers, etc.
Does anyone have any insight on if a device like this can possibly work with the HD500? Why would the OS be able to see it, retrieve the plug-n-play info to correctly recognize it as specifically a Line 6 HD500, but refuse to load the driver??
I'm probably going to end up buying other ones to try. I know Line 6 sometimes uses their hardware as licensing dongle so I'm afraid they may deliberately break the functionality of a USB isolator like this somehow? Every other USB device I tried works fine through the isolator.