I have a laptop that I want to use to listen to music with my Little Dot I+, however the laptop completely ruins ground and causes a ground loop when plugged in. This creates horrible noise through the amp. Using a Grub DAC sort of helps, but only in that it makes most things louder than the noise - the noise stays level. The noise is present in any other device (like my iPod Touch) connected through USB.
So basically, I need something that isolates ground from my laptop and doesn't cost the $100 that a Firestone Audio Greenkey does. Any suggestions are welcome, aside from buying a new laptop.