"I've been playing it at ear splitting levels now for about 2 hours, and I can honestly say it's the best sound I believe I've ever got. It is as clean as can be, with all the tube warmth I could hope for. I have 2 other tube preamps that I can compare it to, and Alembic F-2B, and a Mesa Boogie Studio Pre. The Revelation is cleaner than either of those, plus the botton end is a little punchier sounding.
The Black Box circuitry is built into the unit and has a variable impedance control. It's not a tone control as such, but it does let you shape the high end. I have it hooked up using the 3 chord method. Straight out of the guitar to the BB section, then to the volume pedal from the send, then back to the return.
I'm running a TC Electronic G-Major through the EFX loop. That's a nice added feature. To turn the amount of reverb up or down is just like the old combo amps, a simple turn of the EFX return knob. Just like the old days.
Also I want to add, this is not a paid endorsement. I bought my unit. What more can I say?"