From ZVex;
The Box of Rock (TM) is Z.Vex Effect’s first “distortion” pedal, highly
specialized to simulate the “everything on 10″ sound of a classic
Marshall ® JTM45 non-master-volume amplifier. You may use the Box of
Rock effectively with many different amplifiers, but to get the sound I
heard when I designed it, try it through a Marshall at least once. You
may use your guitar’s volume control to adjust for the exact amount of
distortion you need, all the way down to very clean and clear with most
drive settings. You will notice the words “distortron engine” on the
Vexter version of this pedal (no, that’s not a misprint) on the pedal.
This is what I named my distortion circuit… call me crazy. On the
hand-painted version, the stomp switch on the right is labeled “ROCK”
instead, because our paint brushes are too wide for so many small
letters.
The Box of Rock also contains an extremely high-headroom, unity-to-50X
gain booster with nominal input impedance and low hiss. It is very
similar to the SHO boost circuit, with refinements to make it sound more
like a standard amp input and less glassy. The boost channel can be
used alone or in conjunction with the “distortron engine” channel. The
boost channel follows the distortion channel so that the distortion is
able to hit your amp harder (at a higher volume) when both switches are
engaged, for boosting solos and what-not. Empire Shop favorite!
Look out when boosting what-not.