The GMP56K Digital Signal Processor hacker board kit was developed in 1989-1990 from a design by Daniel Kelley. About twenty of these systems were purchased by hobbyists and composers wishing to build and work with an affordable DSP56000-based system.  An accompanying D/A A/D board was also developed based on the Crystal 4328 D/A and 5336 A/D, from a design by Tom Erbe.

GMP56K on top of preamp rack for hex guitar