Also, is this an okay pre amp?
http://www.zzounds.com/item--ALEIO2
Probably not. It's powered through the USB, so unless you're doing laptop recording, which you aren't if you have the JB3, it won't cut it in the field.
First things first: it's a preamp
and analog-to-digital converter (ADC).
I think the biggest obstacle to field recording with this thing is not so much powering (after all, the MT2496 runs on USB power), but rather interface.
Looks like it's only digital output is via USB, so you'd have to use a laptop for field recording. Your JB3, as a purely digital recorder, would be useless paired with this pre/ADC. I suppose you could run analog out to the JB3, but the analog outputs probably run through an AD/DA stage (analog input > ADC > DAC > analog output) and likely don't sound all that great.Whoops, scanned through the specs too swiftly. Looks like it includes S/PDIF output, but it specifically lists 24-bit S/PDIF input/output. So, two issues:
<1> you'd need to convert the S/PDIF coax (I assume coax S/PDIF, specs usually call out optical S/PDIF specifically) to optical, via something like the Hosa ODL-276. And
<2> need to find out if it outputs 16-bit. If it can't output 16-bit, only 24-bit, it's no use with your JB3 because the JB3 will truncate the least significant 8-bits.