you would have to have a mic preamp in front of this to adjust the gain going in, as it sends out a digital signal.
the JB3 truncates the 24-bit audio to 16-bit, which is not ideal, you can get a better A/D that does 16-bit natively for a comparable price.
as for people with 24-bit recorders, if only this box had 96kHz output, it would be a great.