Up for sale, a 1980s Boss Micro Rack Series Digital Delay model RDD-20 in exceptional condition and in perfect working order. The RDD-20 features continuously variable delay times between 0.75 to 400ms with flat frequency response up to 15kHz. The rack features a Fine knob to adjust the delay time selected, and the onboard modulation offers everything from more chorus-like shimmer to very wide and deep waves of vibrato. The rack also employs a 12-bit PCM system plus analog logarithm compression. This rack unit is also identical in features and function to the RDD-10 from the same Micro Rack series, sharing the same PCB, with just slightly more delay time.

There is additional control over the delay Tone and Level, and the rack boasts 1/4" outputs for the dedicated delay signal as well as a mix between the dry and effected sound. There is also an input jack for an optional Effect Remote external control, and the Polarity control can be toggled between Inverse and Normal, with a Bus jack.

Cosmetically, this RDD-20 is in great shape, with just a scant few faint marks on the enclosure. The graphics are pristine, and all of the original multicolored knobs are present.