Any time you can separate the dirty power from the computer to the dac is a good move. Even the power running along side the signal wire in the USB will cloud the signal going to the dac.
I've also tried the Jitterbug and though it does something... it done it in a destructive way in my system. It seemed to clean up the space between instruments, but I lost some of the delicate nuances and extension on piano notes along with decay.
They are coming up with some great products to address USB problems in CA. You may also want to try the Uptone Audio Regen or the W4S Recovery. The Regen worked wonders on my Bi-Frost DAC, but I went with a PS Audio NuWave DSD DAC and found the USB implementation was so good on the PS Audio that I didn't need the Regen any more.
On the other hand, many people I know that own much more expensive DAC's than I... have had great improvement using the Regen.
Good luck in your quest for better sound in CA.