I'm quite late to this thread, but I recently purchased an ART USB Dual
Pre Microphone Preamp and have been quite happy with it so far.
I have not used its USB connectivity, but jacked its outputs into my
Delta 1010 and it sounds very good - it's nice and quiet and had no trouble
providing phantom power to a Rode NT1A using battery power.
It's a USB1.1 device so if I were to use it as a USB audio device, I'd
only get 16 bits and either 44.1 or 48 KHz from it, but that's fine for
my use. It takes either 1/4" or XLR inputs (both balanced) and gives
1/4" balanced outputs. It can take power from a battery, external power
supply, or USB connection. I have not tried providing phantom power to
a mic using the USB connection.
I don't think this is quite what the original poster was looking for,
but so far I've been very happy with this and wanted to mention its
existence.
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Joe Hartley - UNIX/network Consultant - jh(a)brainiac.com
Without deviation from the norm, "progress" is not possible. - FZappa