I have the Colourbox v2 and I have to say that I love it. It adds some "magic" that I find really really pleasant. The EQ is also really powerful and I very very good. It is true that the gain stage, the distortion it produces, I don't like it for bass. But as a clean preamp, I think it is just amazing.I agree that the Colourbox is clean and the while HPF and gain-stages are def designed for guitar the rest of it works great on a bass. If one is into the gain, well, knock yourself out. The gain stages also seem designed for guitar to me but work on the bass if you are into that sort of thing. I don't personally care for its gain stages on any of my guitars or basses. I have another HPF and other dirt boxen that I would use anyway so there is nothing lost for me there.
The semi-para EQ section is great and along with the preamp and Lundahl transformer sound are the reasons for getting the Colourbox, in mho. There are guitar-centric features but they are simply 'geewizzy' to me and do not detract from the sound of using it for the bass if one simply does not use those features.
I originally bought the Colourbox for bass but I now use it everywhere. Especially acoustic guitars lately.
