I have also wondered about these USB power supplies and how noisy they might be.
I am using one from an old Moto phone, but I decided to order one of these:
http://www.ab-system.hk/index.php?route=product/product&product_id=64
There were some fancy "audiophile" units in Germany but they were quite a bit more expensive.
Greg H.
I don't think 'noise' is an issue... but I didn't like the varying voltage. Even though it did not seem to affect the operation of my boards. And haven't measured real load... too lazy to open a line and stick a meter on. My gut and experience tells me a 1 amp supply is borderline, regardless. I think there are conditions that really spike that line, especially with strong triggers/interference that coincide with other things, like IP access or data sends for e.g..... What effect it has...if any... I don't know. Lacking a scope, and being a retired tech, not an engineer, I can't tell.
And how I could divide 0.24 V by 0.6 and come up with 4 forward biased junctions shows you how rusty parts of me are.!!!

Anybody else catch that error???
