This is a vintage Made in Japan Boss DSD-2 Digital Sampler/Delay pedal. It was a similar circuit with the same holy grail "long-chip" as the classic DD-2 and early DD-3 Digital Delay pedals, with the added functionality of a sampler. Here's a rundown of the controls:

• E LEVEL: This is a blend knob for the wet signal. Full counter-clockwise is 100% dry signal. Turn the knob clockwise to blend in wet (delayed/sampled signal). The wet signal reaches unity with the dry signal around 3:00 on the dial.
• F BACK: This is the feedback knob. It adjusts the number of echoes in the DELAY modes. Full counter-clockwise gives a single repeat. Full clockwise gives infinite repeats.
• TIME: Sets the length of the echo/sample. In DELAY modes, this can give you delay times of 50ms-800ms. In SAMPLER mode, it gives you sample times of 200ms-800ms.
• MODE: This selects between the four DELAY and SAMPLER modes:
• • DELAY S: Gives delay times of 50ms-200ms
  • DELAY L: Gives delay times of 200ms-800ms
  • REC/PLAY: Records and plays samples
  • PLAY: Plays the previously recorded sample. The DSD-2 also has a TRIGGER INPUT that lets you use an external controller to trigger your samples.

This DSD-2 is in good cosmetic condition. The electronics work perfectly. The pots, jacks and footswitch are all clean and quiet. You can power this DSD-2 with a 9-volt battery, a Boss PSA ac/dc adapter, or your standard 9-volt pedalboard power supply.