Info from Brian about his original project:
The Cave Dweller I is a low parts count delay comprised of a single PT2399 chip and fitted for a 1590A enclosure. This ranks as a “mediumi-fi” type circuit, meaning that filtering of the PT2399 is kept at a minimum in favor of a small footprint. While you won’t get quite the fidelity of the Echo Base, for example, it still sounds very, very good and offers a somewhat unique flavor of delay. The effect takes advantage of the two on-board amps of the PT2399 for use as input and output mixers. The feedback and filtering are combined in a unique way which produces a slightly different set of controls than the typical PT2399 delay. This leads to some really “haunting” and musical repeats at long delay times.
You can read more about it in the project documents here, and if you prefer, the PCBs can of course be purchased at http://www.madbeanpedals.com/projects/index.html. Check out some of his other boards while you're there. I just bought a Pork Barrel, Collosalus and StageFright from him which are fantastic quality, and are builds that I would always prefer to opt for PCB over vero.