Development of the M-101 began while Estey was still in Torrance, California sometime in late 1964 or early 1965.
The design parameters called for a fully transistorized unit, with a 1/4" instrument output so the organ could be used with a guitar amplifier (there were no internal speakers). In production form, it would weigh 35lbs, and fold up so it could be carried like a suitcase.
Production of the M-101 was not easy to get off the ground. Development of it began in Torrance but took a hiatus of several months while the company relocated to Harmony, Pennyslvania. The M-101 represented several "firsts" for Estey, including using wave-soldered circuit boards (new technology at the time), and a transistor driven master octave oscillator and transistor frequency dividers.
Estey contracted with Royalite to fabricate the scuff-resistant hard shell plastic case just as they did for the M-series amps. Larry Ludwick made the tooling by first hand-shaping a mock-up of the cover from a large block of wood. Royalite copied it into steel vacuum-form tooling and produced the tops for Estey.
Several engineers worked on the M-101. Tony Price was chief engineer for much of the development of the project, but left the company before it saw production. Jim Evans was instrumental in the early design stages. The M-101 first debuted at the 1965 NAMM show as a prototype, and then again at the 1966 NAMM show with a clear top case, to showcase the PCB boards and transistorized approach. The year in between was spent refining the pedal operations, a redesign of the functions of the lower keyboard, and of course the massive company undertaking of moving from Torrance to Harmony.
Following the July 1966 NAMM show, dealers placed orders for about 300 units. Production of the M-101 probably didn't begin until sometime in late 1966. There were initial build problems with the M-101 in Harmony related to the wave solder manufacturing.
About this time, President Jack McClintock persuaded Jim Evans to visit Harmony as a consultant to help solve M-101 production problems. Evans was one of the California Estey engineers who refused to relocate to Pennsylvania. Evans was a resourceful and keen troubleshooter, and had solved many of the production issues that Estey faced in Torrance. Besides identifying some environmental problems that were causing the wave solder issues, Evans was put in charge of developing test devices to be used during and after manufacturing to ensure full functionality of the M-101.
In addition to Price, Ludwick, and Evans, engineer Bob Warren and Al Allen were closely involved in the M-101 project. It is unknown how many were produced, but figures are estimated to be low (under 500).
At one point, a M-101 package was put together that included a zippered carry case, music rack, bench, and a AM-101 amplifier. The details of the amplifier are unknown. It is likely to be a re-badged M-Series or Pro-Series amp that was in the current catalog, or possibly a new solid state Estey organ amp.
The M-101 keyboards were as follows: The Upper was 49-note with six voiced tones (latin,jazz,surf,blues,R&B,folk) and the Lower was laid out in reverse color keyed fashion as a 25-note keyboard switchable for chords or single-note bass. Two outputs, one for the upper keyboard/solo, and the other for lower keyboard.
A transistorized vibrato used a knob to control speed, and there was a bass percussive accent available for the lower keyboard.
Originally, a microphone input with seperate volume and tone controls was slated for the M-101, but that feature did not make it past the prototype phase. One of these early prototypes is pictured at right with four knobs at the right contorl panel. Later models used six tilting "fingers" for these controls (see picture at the top of the page).