Don't do that. You want a box with an instrument
input and a line
output. I second Dave's suggestion for an M-Audio AudioBuddy. I have
one and it works great (I've seen them as low as $60US). It's a
small, cheap, two-channel mic-pre with instrument (a.k.a. DI) inputs
and line outputs (balanced, which should still work fine with the SB).
Many single-channel mic pres also have instrument/DI inputs, like
those ART tube units (as low as $30US).
A regular DI with output a low impedance mic level signal, which would
still not give you the output signal you want.
I bought a distortion pedal -- hope it'll do the job.
Leslie