oooooh, ok. The iAudio 7 has 3 settings for charging: Normal, slow and off.
I'll try the other settings when I get home tonight and hope that slow works. It does have both MTP and UMS, but being a gPodder user (ok addict), I've never tried MTP anyway. I did some reading on OTG, and I'm pretty sure it's not the cable causing the problem, so I think your suggestion is right. I never would have thought of charging voltage not being available. Thank you.