Boss DSD-2 Digital Sampler/Delay
A delay pedal and sampler used by Prince from the Parade tour through to the early 1990s. It replaced the earlier Boss DM-2 Delay and was replaced by the Boss DD-3 Digital Delay. It has a similar delay chip to the DD-3, but includes a sampler function.
It was mentioned in a 1990 interview. Susan Rogers has mentioned Prince using a "blue delay" pedal in the studio - probably a DSD-2.