There’s been a lot of attention paid of late to some of the classic analog synths from the early days (60s-70s), thanks to a number of recent hardware-related product developments. It started a while back when several companies released hardware reissues of classic synths, most notably Moog Music’s originally-limited-edition hardware reissue of the seminal Minimoog D, which subsequently became a regular part of the current Moog lineup.
More recently Behringer offered up a series of announcements of their intentions to develop several hardware clones of a number of classic models - including the Minimoog - at significantly lower-than-usual price points. This initiated a fair bit of comment and debate on the idea of cloning another company’s technology, but I’m not going to get into that here. Instead, this article will address the question “why did they choose the particular brands/models they did?”
Why Do It?
Long-time synthesists, especially those of us who came up when these classic analog synths were current products, have a pretty good idea why: these are many of the same models that have been emulated in software as virtual synths over last several years by various companies like Arturia, who offer virtual versions of many of the classic synths of yesteryear. Each of them is known for having a distinctive character and history that makes them unique and desirable.
And that’s what this article is about. For those who may not be so familiar with those classic designs, I’ll take a brief look at several of the companies and models that did their part to usher in the age of analog synthesis, starting with the offerings from the grandfather of modern synthesis, Bob Moog.
1. Moog Modular & Minimoog
Bob Moog is generally credited as the man who brought analog synthesis to the masses. Moog Music released many classic models over the years, and the company is still going strong. The earliest models were modular, consisting of separate electronic modules - oscillators, filters, envelope generators, sequencers, etc - which had to be hooked together with patch cables (hence the term “patch” to refer to a preset) by the user. The Moog Modular, which came in several versions, was a behemoth that offered not only a lot of flexibility but the specific “Moog sound”, a product of the oscillators and components used, especially the Moog-designed-and-patented 4-pole “Ladder” filter, which is generally credited with providing Moog synths with the fat, juicy sounds they’re famous for. (A recent article covered several different Moog Modular models, so I’ll refer to that rather than duplicate those descriptions here).
The earliest commercial release featuring a Moog is generally accepted to be Wendy Carlos’ Switched-On Bach, a 1968 album of Bach pieces realized exclusively on the Moog Modular, using the painstaking piecemeal techniques of early electronic recording. Later, rock keyboardist Keith Emerson toured with an especially elaborate custom model, and is credited with one of the first examples of a prominent synth solo on a pop record, the swooping portamentos of his solo on the 1970 song “Lucky Man”.
The Minimoog took a smaller set of those same distinctive components (the edgy oscillators and Ladder filter) and packed them into a smaller pre-wired design with a built-in keyboard - it became the first portable prewired analog synth, and possibly the most popular synth ever. It made its mark on the pop music industry, becoming the first-call synth for fat bass sounds, and as I mentioned at the top, a top-of-the-line reissue is currently available from Moog itself, as well as the announced budget clone from Behringer.
2. ARP 2500, 2600, & Odyssey
Back in the early days, Moog Music’s biggest competitor for a while was ARP, founded by Alan R Pearlman. ARP also offered a large modular synth, the 2500, to compete with Moog’s Modular designs. Rather than patch cables, the modules were mostly hooked together via a large switch matrix (see Fig 3). The 2500 had a somewhat different sound, not as fat as the Moog but a rich, bright overall tone, capable of a lot of different tonal colors. It’s most famous credit is probably its on-screen appearance in the climactic scene of the movie “Close Encounters of the Third Kind”, where it provided humanity’s musical counterpoint (the movie’s famous 5-note motif) to the visiting spaceship.
ARP also brought out a smaller, mostly prewired model, the 2600, and if the Minimoog is #1, then many would argue that the 2600 is a close #2. Though prewired, it had numerous optional patch connections that offered a great deal of flexibility for sculpting more unusual sounds, compared with the Minimoog, and it included some extra modules that offered features like Ring Modulation and Sample & Hold functions. Different versions utilized different filter designs, an aspect addressed by some software emulations (i.e. Arturia), and its companion sequencer unit was very popular. The 2600 was widely used by many 70’s musicians, notably Pete Townshend of the Who (Who’s Next) and Weather Report’s Joe Zawinul (Mysterious Traveler). Even more scaled-down models followed - the portable ARP Odyssey was a big hit, and has been emulated by a number of modern companies, in both software (GForce Oddity) and hardware (Korg).
3. Oberheim SEM & OB-Xa
The very earliest analog synths were monophonic, but of course eventually polyphonic models were developed. Another synth pioneer, Tom Oberheim, provided musicians with a number of classic designs. The SEM - it stands for Synthesizer Expander Module - was Oberheim’s way of offering a modular approach to polyphony.
The SEM was a self-contained two-oscillator synth in a box, with VCO x2, multimode VCF, & EG x2. The idea was that you could combine multiples of these with a companion keyboard to achieve polyphonic capability - this approach produced the Oberheim 4-voice (4 SEMs) and 8-Voice (8 SEMs) models.
Thanks to the SEM’s 2-pole filter the sound was a little thinner than some, but when played polyphonically, some nice rich, detuned synth pads could be had. The SEM-based models had one awkward aspect - since the modules were independent, you had to duplicate the settings on each one by hand if you wanted a big fat polyphonic sound. Oberheim’s designs evolved into more traditional polyphonic synths, with up to 8 and even 12 voices and a common set of controls - perhaps the most popular was the OBXa.
The OBXa was available with up to 8 voices, including a splittable keyboard. The design updated the SEM’s oscillators and filter with Curtis chips, and it continued the Oberheim tradition of rich polyphonic sounds, becoming known for its synth brass and string patches. Probably its greatest claim to fame (or infamy, as many would suggest) is it’s featured use on the Van Halen song “Jump” - it’s a good example of the Oberheim sound, even though the song has fallen out of favor with many listeners due to massive overexposure.
Currently, besides numerous software emulations of Oberheim models (including the free OBXD), Tom Oberheim offers hardware reissues of the SEM and 2-Voice, and in collaboration with Dave Smith (see below), the OB-6, all inspired by the classic SEM tone. And of course, a version of the OBXa is on Behringer’s list of proposed low-cost hardware clones.
4. Sequential Circuits Prophet
Dave Smith, the founder of Sequential Circuits, was another synth pioneer, and is also still active in the industry, creating modern instruments like the Evolver and PolyEvolver synths. One of his early claims to fame was as a strong proponent for the industry-wide adoption of the proposed MIDI standard for synth/keyboard intercommunication. His other big achievement was Sequential Circuits’ first Prophet synthesizer, the Prophet 5.
The Prophet 5 was a five-voice polyphonic synth with two voices per note for a rich sound. It combined a purely analog sound engine with a digital scanning keyboard and patch memories (only 32, but that was groundbreaking back then!). Its characteristic bright sound was a product of its flexible “poly-mod” option, which allowed Osc 1 to be modulated by Osc 2, and its Sync feature, which imparts an edgy sweep to Osc 1 - an analog synth effect called oscillator sync or “hard sync” (The Cars: Let’s Go).
The earliest versions used SSM chips from E-mu, but later revisions switched to Curtis CEM chips - some felt the older chips had a richer sound, but they suffered from unstable tuning (an issue with many early analog synths). Despite Dave Smith’s advocacy for the MIDI standard, the original Prophet predated it, but subsequent models were capable of being MIDI-retrofitted. A later version increased the polyphony (Prophet 10), and Dave Smith Instruments currently produces modern high-end versions, the Prophet 6 and Prophet 12, along with other innovative designs.
Besides the four companies whose products I’ve mentioned, there were plenty of smaller companies making synths in those heady days, and some of them have become cult classics in their own right. A British model, the EMS VCS3 (a.k.a. the “Putney”) was used by Pink Floyd, and a nice virtual emulation is available from French software company XILS-lab. Mini synths like the Wasp, and small synths like the OSCar brought their own sounds to the party.
The OSCar, from OSC, was a basically analog design but featured digital oscillators, and included a little additive synthesis capability, giving it its own unique sound. A software emulation, the impOSCar (get it?) has been around for a while, and it’s another model on Behringer’s wish list.
Since I had limited space, I kept this list primarily to just four of the earliest synth makers and their models, stopping short of including any of the many classic designs from Roland (several of which I was a proud owner of at one time or another), Korg (ditto), or Yamaha, let alone the advanced designs from Don Buchla. But back in the day, these were the big four - the models everyone wanted, but few could afford (at least initially) - and each one contributed something unique and special to the evolution of analog synthesis, making them perfect targets for modern emulations and reissues.