Electrocomp 100/101 Edit
The Electrocomp 100 was EML's first model, not counting the "blue meanie" educational synths whose construction EML took over from another company at its formation. The 100 was a four-VCO, semi-modular synth which competed with the ARP 2600. It had one more VCO than the 2600 and cost less, due in part to EML's pioneering use of early integrated circuits. Military-spec components were used generously in the Electrocomp 100's deisgn, giving it high reliability and stability. It had a duophonic keyboard, and the ability to assign different combinations of the VCOs to the two keyboard control voltages. However, like most EML synths, it lacked a pitch wheel or mod wheel. Three of the VCOs had continuously variable waveforms from sawtooth to triangle to square, and VCO1 had five selectable waveforms.
Two of the VCOs were switchable to low range to use as an LFO.
The Electrocomp 101 was an improved model based on user feedback, containing an improved VCF and adding several features including a sample and hold, and an amplitude modulation / ring modulation capability to the VCA. This became EML's most popular model, with about 1000 units sold.
In the early '70s time period, EML used two different panel color schemes. The earliest EML synths had panels with a cobalt blue background and white graphics. Others use a panel with a semi-gloss silvery finish, that can look either gray or beige depending on the ambient light; it uses black graphics. Most of the Electrocomp 100s have the blue panel, although at least a few were made with the silver panel. All of the 101s have the silver panel.
Electrocomp 200 Edit
This was an expander module for the 100/101. This contained three VCOs, low pass and high pass VCFs, a VCA with amplitude modulation capability plus a separate ring modulator (!), a preamp, and a mixer with stereo output. An oddity is that most of the input and output jacks are designated with numbers, for which the user most refer to the manual to see what the jack does if it isn't apparent. Both blue-panel and silver-panel 200s were made.
Electrocomp 300 Edit
This was an oddity; an expander module containing a single VCO. Its notable feature was a Buchla-ish control voltage generator consisting of a 4x4 array of pushbuttons and corresponding knobs. Pressing a button caused the module to output the voltage selected by the knob that went with that button. There was also a small group of signal routing switches and jacks. This was intended for experimental musicians and only a handful were made.
Electrocomp 400/401 Edit
This was a combination of a tabletop, semi-modular synth module (400) and an innovative analog sequencer (401). Although sold separately, the two were intended to be used as a package; their cases hinged together to fold into a single road case, and a multi-conductor cable conveyed signals from the 401 to the 400. The 400 was fairly conventional, with two VCOs, an LFO, a low pass VCF, and a VCA. The envelope generator was only an AR type; it was intended that the user would use an envelope generator built into the 401.
The 401 was a highly configurable sequencer capable of up to 64 steps. Notes were continuously variable or could be quantized by a digital quantizer circuit. The sequencer included a 16-segment envelope generator which could be synchronized to the sequencer clock; its output was automatically routed to the VCA in the 400.
Only a handful of these were sold. The 401 was probably too far ahead of its time for 1975; similar capabilities would not appear in other products until the first digital sequencers in the early 1980s. And because of the control voltage scaling that EML used (more on this below), the 401 could not easily be used to control other synths.
Electrocomp 500 Edit
This, the final product in the Electrocomp series (and EML's last product other than the Polybox and the ill-fated Synkey), this was a performance synth intended to compete with the Minimoog and the Odyssey. It was basically a re-packaging of the synth circuitry from the Electrocomp 400, with a keyboard and necessary interface circuity added. It came to market too late (around 1976) to make an impression against the other makes it was competing with, and acceptance was probably hindered by EML's odd aversion to pitch and mod wheels. About 200 were sold
EML Scaling Edit
WIth the Electrocomp products, EML attempted to establish an industry standard for control voltage scaling of 1.2 volts/octave. This makes sense when one considers that this scale amounts to 1/10 volt per half step in the chromatic scale; it would have made the math a lot simpler when adding control voltages to, say, transpose the output of a VCO; to transpose up a perfect fifth, one would add 0.7 volts. But it didn't catch on; 1 V/octave became the industry standard, and it left EML with a situation where their products were difficult to interface with analog synths from other manufacturers. The situation might have improved had EML offered a scale conversion box, but it never did.