Roland System 100M
A modular you could actually afford - if you were willing to patch it, tune it, and never let it leave the bench.
Overview
The System 100M arrived when a modular synthesizer could cost as much as an average house. Roland's pitch was blunt: build a synth studio from low-cost modular components. That framing comes straight from Roland's own advertising, which in 1977 billed the 100M as the answer for players who wanted modular flexibility without a modular mortgage, as seen in Modern Recording (May 1977, p.53). Whether the ad copy held up is another matter, but the price of entry was the whole point of the system.
Physically, the 100M is a set of compact modules in a metal case, sized to sit on a desk rather than dominate a room. The service documentation gives the scale: modules run roughly 104 mm wide by 230 mm high by 199 mm deep, and most of them weigh around 1.2 kg - about 2 lb 10 oz. That's small enough that a modest rack of them feels like an instrument rather than a piece of furniture, and heavy enough that the metalwork doesn't feel like a toy. Power comes from an external supply. The accessory lists show the system was sold internationally with region-specific AC adaptors, and 100V, 117V, 230V, and 240V variants all appear in the parts documentation.
The module names read like a taxonomy of subtractive synthesis: the M-110 VCO-VCF-VCA, the M-112 dual VCO, the M-132 dual CV/audio mixer and voltage processor, the M-140 dual envelope and LFO. Each module handles one job. The M-110 puts an oscillator, a filter, and an amplifier behind a single panel. The M-112 gives you two oscillators to stack or detune against each other. The M-132 is the utility hub, mixing signals and processing control voltages. The M-140 covers modulation and envelope duties. You buy the pieces you need and patch them together.
The specs that survive in the documentation are the kind a patcher cares about. The M-140's LFO runs from 0.05 Hz up to 30 Hz, with a gate/trigger input impedance of 50k ohms and control sensitivity of 1V/octave, so it tracks a keyboard CV like the rest of the system. Its output is 10V peak-to-peak into 1k, with a delay time adjustable from 0 to 7 seconds and sustain spanning 4 milliseconds to 15 seconds. That means very slow, long sweeps at the bottom end and a usable delay for swelling modulation in after a note starts. The M-132's signal path is a different animal: a 512-stage BBD delay line with delay time from 2.56 ms to 25.6 ms, a balanced modulator/demodulator built around the LM1496, carrier suppression of 65 dB typical at 0.5 MHz, and total harmonic distortion around 0.4%. That's a short delay - not an echo, more of a thickening and comb-filtering tool.
The tuning and calibration procedures in the service notes show what ownership involves. Roland's instructions call for leaving the test equipment powered for a 20 to 30 minute warmup before adjusting the M-180 and M-181, keeping the room at a normal, constant temperature, and checking the keyboard CV against a 1V/octave reference to within 1 mV. Adjustments are iterative. Turning one trimpot affects the previous adjustments, so the procedure loops back to step one and you go again. Oscillator range, triangle straightness, and rectangular duty cycle are all trimmed by hand with a nonferrous tool. This is not a synth you set and forget. The documentation assumes the owner has a digital voltmeter and knows how to read a Lissajous figure.
That's the honest shape of the 100M: a system that rewards patience and punishes neglect. It was never the cheapest way to make electronic music, and it was never the simplest. But it was, by the standards of modular gear in the late 1970s, an accessible one, and the people who committed to it tended to commit hard.
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