I build lots of bass widgets from scratch, but this one's based on the ESP preamp board from project 27, here: http://sound.westhost.com/projects-5.htm . I also used his power supply board, project 05 here: http://sound.westhost.com/projects-4.htm . This has been replaced by project 05A. The toroidal transformer was scrounged from an old Allen & Heath mixer. I used the best Clarostat and Bourns pots I could find, and a rack case from Sescom. The opamp is a Burr-Brown OPA2132. If you're looking to save money by rolling your own, forget it in this case. I probably have nearly $200 in the project at this point, maybe more. And it's a very simple design with no spiffy extra features. But if you built it into an existing case and have some usable parts kicking around, it could be reasonably cost effective. One caution: the circuit boards are pretty unforgiving of rework, so you might want to buy two preamp boards and figure on throwing one away by the time you dial in all the values. I managed to do several mods without completely hosing the board, but I did have to do some trace repairs. Some pictures, sans front panel graphics (which are in process): How's it sound? I'm liking it as a replacement for the preamp in my AI Focus for fretless BG. I didn't intend it to be a recording preamp, but here's a noodley sample recorded straight to my soundcard, using my Crescent Moon fretless 4, with a Bart preamp and strung w/ T-I Jazz flats. I'll shoot for a better recording eventually, this one is a bit noisier than it needs to be, mainly due to some issues with the onboard electronics in the bass. Scary Bass Preamp Clip Questions, comments, and general derision are welcome, as always.