Suweet! The wife spent the night at the grandkids, so I could wring this out. It makes my DD Lipstick Tubes sound like Cool Rails. I don't know why, but it's slightly different than the original SFX-01. The SFX-01 makes things louder, while this one seems to add some spank and punch. (Like a CR.) Putting the knob at 12 o'clock is the perfect amount of boost.
This thing was definitely designed for singles. (IMHO.) It adds the same spank and punch to my Peavey T-30, with the "square-ish" rail singles, and especially to my Patriot with the big Super Ferritte singles. (Think "rail" Phat Cats.) The small singles sound like Cool Rails, and the big singles sound like Hot Rails. But different. Just loud fun.
Humbuckers just get louder. Except the Dano Lipstick Tube humbuckers. This thang loves Lipstick Tubes.
On the down side, the resonant switch does nothing. I wonder if mine is broken. There is no difference as you strike a note and the flip the switch back and forth through it's positions. None at all. I'm doing guitar>cable>booster>cable>amp. When I get a chance, I'll open her up and see if everything is wired right.
But that's ok. It's sweet just as it is. Did I mention that this thang loves Lipstick Tubes?
The notch positions, #2 and #4 are especially sweet. Jingle jangle punch and spank. Suweet.
:banana: