Nakamichi had several models in this 6xx range, starting from 660ZX and ending with famous 682ZX. Produced at the end of 70’s.
This model – Nakamichi 680ZX is specific in the way it has two running speeds: standard 4.76 cm/s and the other which is half of it, around 2.4 cm/s or 15/16 ips.
Nakamichi 680ZX also has RAMM – Random Access Music Memory which is complicated name for track search, in case You want to move, say, three tracks forward or reverse. It also supports cue and review during which the used can hear output sounds in high or low speed mode, which is more used by professionals.
Nakamichi 680ZX has manual level calibration system. It is based on 400 Hz oscillator an 6 trimmers accessible from the front panel. The actual goal is to get VU/Peak meters get to the mark point for both channels. There are additional six trimmers designed for half speed level calibration.
Gone through by a certified technician, this deck works perfectly. Condition, both cosmetically and operationally is excellent. There are a few very light marks on the top from normal use.