I've been looking for a small bass preamp I could use for studio purposes and stumbled upon this little thing a few months ago. For the price you pay, you have an outstanding product in terms of quality of sound and features. Even though the Quilter Interbass is small (its size is roughly like a Big Muff pedal), its build is pretty sturdy, with metal switches and solid knobs. You can use it on either active or passive basses, it has a 3-band EQ covering the bass-specific frequencies (100Hz, 300Hz and 1k) and a separate gain stage.
With one balance line output (that can become a headphone output by flipping a switch), an FX loop send-return and a Speaker Only output (which can get up to 45W of power, making it pretty decent for small to medium venues), it's evident that the folks at Quilter know what they are doing when it comes to packing a piece of gears with all the necessary features and no frills (there are no embedded FXs, tuner or compressor).