Offered here is an exceptionally rare and historically significant Minimoog Model D (serial #4993), having been owned by Dr. Tom Rhea, former Moog salesman, respected electronic music historian, author, and one of the foremost authorities on the history of electronic instruments.

Beyond its historical importance, this instrument has undergone an extensive restoration and technical upgrade by an experienced technician. The work focused on preserving the instrument's original character while improving long-term reliability, tuning stability, and performance. The result is an instrument equally suited for serious collectors, recording studios, and tasteful musicians.

The switchable distortion profile of the VCA is of particular interest.

Below, from the service technician:

"1. REV 1 Jim's Circuit (Trumansburg) had the original moderate distortion profile.

2. REV 2 Luce "fixed" it sometime in 73 and removed practically ALL distortion. Very few production units from the factory were built with the Luce "no distortion" circuit profile.

3. 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 unit has internal switches allowing for the user to switch between REV 1 and REV 3 distortion profiles."

Service History

The instrument received a comprehensive overhaul that included:

• Keyboard removed for servicing, with buss bars and contacts cleaned 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% CV summing 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 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, the VCA switch boards were added internally, allowing for quick selection between earlier and later VCA distortion profiles.

Condition & Notes

• Original ribbon controller installed in place of the standard pitch wheel.
• Noticeable cosmetic ding on the wooden cheek panel beneath the Mixer section (see photos).
• Includes a custom-built flight case.
• Formerly owned by Dr. Tom Rhea, former Moog salesman and internationally recognized authority on electronic music history.