For you guys that think that the O2 will "work better or sound better???" on el crapo PC usb 5 volts I have used the ODAC on over 20 pcs of all types and flavors. I also used and external very high dollar DC power supply and I could not hear any real audible differences.
All the measurements that the designer took and are published on the other site meet or exceed anything that might cause the loss of transparency etc or the ability of it to do what it was intended to that is to be a excellent digital to analog convertor.
The ODAC like the O2 was and still is an experiment to prove to the world that great audio can be had at less than astronomical prices....
Unless you really have a really poor PC USB implementation and violate the USB specs there should be no real world difference in what the ODAC does.
You can easily splice pure DC to power the ODAC to see what "pure DC" will do.....simple DC batteries have no AC ripple or warts...even mega buck AC to DC power supplies have issues....
All the best
The main reason why I'm interested on the doodlebug is primarily because I have other DAC's that cannot have the same regulated power implementation as the ODAC (i.e: ELE DAC EL-D01 that goes for $15 max). If I truly cannot hear a difference on the ODAC, then I am free to use it somewhere else. I'm sure my USB microphones may benefit from a cleaner power.