Offered here is a rare and historically significant original Minimoog Model D (serial #4993) owned by Dr. Tom Rhea, longtime Moog Music employee and respected electronic music historian. In 2023, Tom wrote Electronic Perspectives: Vintage Electronic Musical Instruments, which includes all 52 of his celebrated "Electronic Perspectives" columns in Keyboard magazine during 1977-1981. This 400-page book shows the first century of electronic instruments in photos, stories, and soundson two audio discs. EP: VEMI includes the first-ever Moog and Buchla recordings, previously unreleased.

This Minimoog has the improved stability and pitch accuracy of a modern instrument, while retaining the sound of the original Trumansburg "phat sound" Minimoog.

The available switchable distortion profiles is of particular interest.

Below, from the service technician (slightly abridged):

REV 1 Jim Scott's circuit (Trumansburg) had the original "phat sound" distortion profile that is preferred.

REV 2 personnel at Moog Music "fixed" it sometime in '73 and removed practically ALL distortion. Very few production units from the factory were built with this "no distortion" circuit profile.

REV 3 Tom Rhea demands that the distortion be put back, and they OVERSHOOT Jim's Trumansburg circuit with the later (and final) Williamsville circuit, which ended up having the highest distortion of all.

This Minimoog on offer has internal switches allowing the user to switch between original "phat sound" REV 1 Trumansburg and later Williamsville REV 3 distortion profiles.

Service History

The instrument received a comprehensive overhaul that included:

• Keyboard removed for servicing, with buss bars and contactscleaned and polished.
• Key contacts aligned for proper trigger sequence (CV-before-S-Trig).
• Existing keyboard was already rebushed, so no rebushing was needed.
• The original 6-pin Cinch keyboard connector was replaced with a new Molex connector to eliminate intermittent connection issues.
• All PC boards removed and serviced.
• Power supply and Boards 1–4 fully recapped.
• Metal-can trimpots were replaced throughout with modern cermet trimpots on adapter boards.
• Oscillator board updated with new chip sockets, low-offset/high-stability 741 op-amps, and precision 0.1% CVsumming resistors to improve oscillator tracking, pitch stability, tuning, and temperature stability.
• Octave rotary switch wafers for parallel switch wafers to reduce switch resistance, add redundancy, and improve tracking and tuning.
• Octave-scale CV resistors (on rotary switches) replaced with new 0.1% high-accuracy types.
• Opamp in octave buffer board replaced with a low-offset, high-accuracy types.
• All non-sealed front panel controls were cleaned and flushed.
• Instrument fully reassembled, power supply adjusted, preliminary full calibration. Reassembled, tested, burned-in, touch-up calibration, retested.

Additionally, the decay front panel pot on filter EG was at one point replaced with a non-Allen-Bradley type pot, which had a slightly different log taper. This was discovered when Tom Rhea's Minimoog Sound Charts did not sound correct when set up as published. This pot was replaced with a genuine AB pot so that the filter envelopes would sound correct when using the sound charts.

And lastly, switch boards were added internally, allowing for quick selection between earlier Trumansburg "phat sound" and later Williamsville distortion profiles.

Condition & Notes

• Original ribbon controller installed in place of the standard pitch wheel. Hear Tom's 2-minute YouTube demonstrating this ribbon's capabilities at the link included.
• Noticeable cosmetic ding on the wooden cheek panel beneath the Mixer section (see photos).
• Includes a custom-built flight case.
• Owned by Dr. Tom Rhea, former Moog Clinician and internationally recognized authority on electronic music history.