E-mu Modular System (1972–1979)
Before the Emulator, before the SP-12, there was this — the hand-built modular that put E-mu Systems on the map and rewired the sound of 1970s electronic music.
Overview
The E-mu Modular System was the company's first product, developed between 1969 and 1972 and first assembled in 1971-72, years before E-mu Systems was even formally founded in 1971. It was one of the first modular synthesizers ever built, and it remains one of the most respected. When Polyphony (November 1981, p.23) interviewed Dave Rossum, the magazine's intro noted that the E-mu modular system "has set the standard by which all other modular systems can be judged." That's a period assessment from a publication that watched the whole category emerge.
The system was fully modular, built from 19-inch rack-mounted modules installed in a wooden cabinet. Over 30 different modules were available at various points in the production run: VCOs, VCFs, VCAs, envelope generators, LFOs, mixers, sequencers, keyboard controllers, noise generators, slew limiters for portamento, ring modulators, sample and hold, reverb, and even analog delay modules. The 5-octave keyboard controller used a 10 V/octave control voltage standard, with gate and trigger control signals handling note on/off logic. It was a high-end professional instrument. You needed to know what you were doing before you patched a single cable.
Key Features
Over 30 Modules, All Designed by Dave Rossum
Every module in the system was designed by Dave Rossum. In that same Polyphony interview (November 1981, p.24), Rossum explained the philosophy: "We built modular systems first because with a big enough modular system, you can do anything. We have a huge variety of modules - if we think of something that can't be done with our system, we'll add the modules necessary to do it. For example, we have five different kinds of filters." The system wasn't a fixed instrument. It was a growing toolkit, and when a client needed something the catalog didn't cover, E-mu built it.
State-Variable Filters and 10-Octave Tracking VCOs
The filters were state-variable designs, which gave them a flexibility that simpler ladder filters couldn't match. The VCOs were the real stars, though. They were designed to track accurately over 10 octaves, which was extraordinary for the era. Most analog oscillators of the early 1970s drifted and wobbled; E-mu's tracked like a laboratory instrument. The output of the VCOs could be shaped, giving users additional timbral control beyond the raw waveform. This precision is why the system's sound was known for being very clean and precise, a deliberate contrast to the warmer, fatter sound of some competing modulars.
Color-Coded Front Panels
Each module had a dark gray front panel with white legends. The design was color-coded, with knobs and patch points marked in colors that helped you trace signal paths at a glance. With dozens of patch cables running everywhere, that made complex patches significantly easier to build and debug.
Transistor-Based to Integrated Circuit Evolution
Early units used transistor-based circuitry throughout, but as the production run continued, later modules incorporated integrated circuits. This wasn't a cost-cutting move. It reflected the rapid advancement of semiconductor technology through the 1970s. Rossum acknowledged the constant change in that Polyphony interview, noting that customers sometimes got upset because "our instruments are constantly evolving and improving." The modular architecture meant you could upgrade individual modules over time, mixing early transistor VCOs with later IC-based filters in the same cabinet.
Historical Context
The E-mu Modular System emerged while the synthesizer was still defining itself. It competed directly with the Buchla and Moog modulars, the two established giants of the field, and positioned itself as an alternative to both. The first system sold in 1972 was a large 16-module configuration, and it set the tone for what followed: serious, expensive, professional equipment.
The system was also one of the first synthesizers to use digital control in some modules. In that same Polyphony interview (November 1981, p.25), Rossum recalled how Dave Smith "had come to us for design help with other projects; when he decided to get into a synthesizer, he came over and basically started picking our brains from the beginning."
The list of notable users reads like a who's-who of 1970s electronic music: Klaus Schulze, Tangerine Dream, Kraftwerk, Herbie Hancock, Stevie Wonder, Weather Report, The Cars, Devo, and The Residents all used the system. That's an extraordinary range — from Berlin School sequencer runs to funk and new wave. The system's clean, precise sound made it versatile enough to fit into all of those contexts.
Production ran from 1972 to 1979, when E-mu replaced the modular with the E-mu Audity.
Collectibility & Value
These systems are extremely rare. Only a small number were built in the first place, and decades of studio use, shipping, and storage have taken their toll. When complete systems do appear on the market, they command serious money, though exactly how much depends on who you ask. Sources report systems selling for over $20,000 in recent years, while other documentation suggests complete systems typically trade in the $10,000 - $15,000 range. The truth is probably somewhere in between, depending on configuration, condition, and whether the system has been properly maintained.
Maintenance is the real concern. The electrolytic capacitors in old E-mu modules are prone to drying out and need to be replaced. That's standard vintage electronics care, but the stakes are higher when the modules are this rare. The power supplies on these systems are also known to fail, and replacement parts are hard to find. E-mu Systems itself stopped supporting the Modular System in the 2000s, so don't expect to call the factory for a schematic or a spare VCO board. Budget for a full recap and power supply rebuild before you trust one in a session.
A working, well-maintained system is a piece of electronic music history, the instrument that launched the company. These aren't museum pieces that can sit untouched. They need regular exercise and occasional surgery to stay alive.
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