sentences:  The Mitsubishi X-80 2-track 1/4 inch digital recorder from 1980 predated the ProDigi format and has many similarities, although it used an unusual 50.4 kHz sample rate, and is not directly compatible.However, Mitsubishi did build the capability to play back tapes created on an X-80 into the X-86 series machines.Only 200 X-80's were manufactured.