Synthesizers and Samplers
MODEL D
page 2 of 23
page 2 of 23
Calibration Procedure
The main printed circuit board (PCB) of the MODEL D has various test points and miniature potentiometers (trimpots) that allow
the various calibration and adjustment procedures to be carried out. This involves lifting up the front panel to allow access to the
bottom side of the PCB.
Three main calibrations can be carried out:
1. The PITCH CV can be calibrated using a computer to send a SysEx command, an external keyboard, and a digital DC voltmeter.
See PITCH CV Calibration.
2. The oscillators can be calibrated using a guitar tuner or the internally-generated A-440 concert pitch, and an external
keyboard. See Oscillator Calibration.
3. The Octave RANGE can be calibrated using an external keyboard. See Octave Range Calibration.
A-440 Reference
The MODEL D A-440 pitch is generated and regulated by the MCU and there is no adjustment required. This set frequency is
used as a reference in the following procedure to calibrate OSC1.
Important Note about Reset
If you have previously adjusted the MIDI IN Transpose or MIDI Note Zero Volts, you MUST reset the MODEL D to its factory
settings before doing the following procedures.
Preparation
Before doing the PITCH CV calibrations, become familiar with, and practice the procedures for sending SysEx
commands to the MODEL D. In this way, you will spend less time with the calibrations.
