E-mu Systems got their start from very humble beginnings in the early 1970's and they were based out of Santa Cruz, California. Founder Dave Rossum and a few of his friends made their first E-mu synth called the E-mu 25 in 1971 and only two were made and delivered. In 1972 they started building the E-mu Modular systems and they produced just over 250 of these modular synthesizers for famous artists, such as; Herbie Hancock, Hans Zimmer, Frank Zappa and Michael Boddicker to name but a few. They were also sold to several universities for their budding electronic music programs. These E-mu modular synths were all custom-assembled and they became known for their remarkable stability and these synthesizers were sturdier and would stay in tune longer than competitive models offered by Moog and ARP at the time. The E-MU Modular featured the world's first microprocessor-controlled polyphonic keyboard and sequencer (control voltage, of course, as this was years before MIDI), which was also one of E-MU's first patents. The E-Mu modular system is a true modular system, but it also featured a “firm-wire patch” in which any front panel patch could be made in the rear of the instrument. Inserting a front panel patch would then bypass the firm-wired patch, so you could store a favorite voicing or frequently used connections by using this unique firm-wire patches. These firm-wire patches were not permanent, and they could be easily changed by the user.

It is believed that today, there are less than 100 or so of these E-mu Modular synths still around. Notably these E-mu's oscillators were virtually drift-free because of E-mu's unique circuitry designs. Their filters were also cleaner than the Moog and ARP, however that wasn't always considered a good thing, because many people liked the grittier sound of a Moog Modular.