Another review of mine! I figured that the more of these I can do, the less "in the dark" our fellow bassists will be.
So, this one was rather interesting... the GT2 is famous for its use by Justin Chancellor of Tool. It's not exactly "bass-friendly" though.
SIZE: Same as the SansAmp BDDI, or any other pedal in the Hammond 1590BB enclosure (like the new EHX XO series pedals).
POWER: Standard 9V Boss-style adapter or 9V battery.
CONTROLS: The GT2 has four knobs - Level, Highs, Lows, and Drive. In addition, it has three switches - a MIC switch for adjusting the simulated cabinet miking position (Classic, Center, and Off-Axis), a MOD switch for gain style (Clean, Hi-Gain, and Hot-Wired), and an AMP switch for amp model (Tweed, British, and California).
SOUND: Honestly, I expected more from this pedal, even though I went in knowing quite a bit about what it was designed for and what it could do.
I know it's a guitar pedal, so the low end issue didn't surprise me - I just hoped it wouldn't be too bad. The low end loss is significant no matter how you slice it - crank up the lows if you want to make it more usable on bass, or use a blend pedal. It does have a crunchy midrange if you don't scoop the mids, and happens to be very aggressive, which is nice for cutting through the mix, but you'll lose those thick bass frequencies at the bottom. So... approach this pedal with that low end loss in mind.
As for the switches...
The MIC switch didn't seem very useful on bass. There is a difference between the settings, but only one was okay. I can't remember which one at the moment... I think it might've been the Classic setting, which simulates distant miking.
The MOD switch is somewhat useful for setting the range of gain, if you really want to push the GT2 to the edge. However, at higher gain on bass, you'd be hard-pressed to tell the Hi-Gain and Hot-Wired modes apart. The clean range is a joke - if you really want a good clean bass sound, opt for a SansAmp BDDI, since the low end is butchered by the GT2.
The AMP switch is somewhat useful. The Tweed sound (Fender-ish tones) was okay and best used for clean, as it had unpleasantly harsh high end at high gain settings. The British (Marshall-ish) sound lacked thickness and crunch compared to the California (Mesa-ish) setting. The California setting brings out the same sorts of tones that have made Justin Chancellor's bass playing famous, and is IMO the best setting on this pedal. It's aggressive, crunchy, sensitive to even mild touches, and harmonically rich even on lower frequencies. Unfortunately, that low end loss is always there.
All of the settings had a lot of brightness to them, but it bugged me in the same way the SansAmp BDDI's Presence knob bugged me - a bit harsh, noisy, and sensitive to even light touches.
This is definitely one of those pedals that'd be far more promising if used in a multi-rig setup, or with a blend pedal.
Overall... it does sound great after some careful tweaking. There aren't many distortion pedals like it. It could certainly use more low end, IMO, but depending on how it's used, you may not necessarily need that extra bottom.
SCORE: 
