I just recieved this little guy in the mail. I saw another TB'er with one & had to try one out for myself. Basically, it's just a passive tone control in a nice hardwood box. While that may sound pretty boring - man this thing is great!!! We all know how limiting the typical passive tone control can be (treble attenuation). While the old-school tone knob certainly works, there is a lot more going on inside the Bbox. There are 4 or 5 different capacitators as well as a tiny transformer inside (along with the funky 6-way rotary switch). The transformer reminds me of the switchable "thump" circuit in old Gibson Hollowbodies. The wooden case is flawlessly constructed with a full copper shielding job. The sounds are anything but straight-forward. The first setting is just the bypassed instrument-only tone. The next 5 are all different shades from treble reduction, to big pillowy texture, to gritty compressed flavors. I was a little concerned that it would just be different degrees of tone roll-off. But that is far from what the box actually does. (A previous TB'er posted some sound files, which were great, but I'm not sure they did the box justice.) I can't wait for my next session to use the Bbox. It really does create some cool, funky changes to your sound!