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The Moog Sonic 6

Call me a heretic if you wish, but I sometimes wonder why we make such a fuss over Bob Moog and the synthesisers that bear his name. Sure, they were good, and in one or two cases, they were excellent, but there were an equal number of flops and - to be polite - almost as many blunders.

In part, the reverence must be due to the fact that Moog was a pioneer, a trailblazer who, back in the 1960s, offered us magical new sounds and new musical experiences. Indeed, his early instruments helped to create entire genres of modern music where none had previously existed. But is this sufficient reason to worship Moog, and to afford him the title of "Godfather of Modern Synthesis" as many now do?

To answer this, I'm going to offer you an alternative view of the development of Moog's synthesisers. To be honest, many of the events described in this RETROZONE took place when I was barely out of short trousers, and I can't be sure that they are the only interpretation of the story that unfolded between 1969 and 1972. Nonetheless, I'm fairly sure that I've got it right, so I'm going to use this month's retro to explode some myths...


During the late '60s, R A Moog Inc. was based in Trumansburg NY, and employed an engineer and designer named Gene Zumchak. It was Zumchak, together with fellow engineer Bill Hemsath, who badgered Bob Moog to design an integrated synthesiser that players could use without resorting to a spaghetti junction of patch leads. Unfortunately, Zumchak and Moog were not what you could call chums, so Moog declined to develop these ideas, and Zumchak left the company. Was he pushed or did he jump? I don't know, but it seems likely that his exit was not wholly voluntary.

Following his departure from R A Moog Inc., Zumchak was approached by a chap named Bill Waytena, who claims independently to have had the idea that an integrated synth would be of interest to schools and colleges. Precisely how Waytena and Zumchak (who, legend has it, were both Ukranians) met is shrouded in history. However, there's no doubt that Waytena and his company, muSonics (small "m", capital "S") made it possible for Zumchak to design and build the Sonic V - the integrated synthesiser that Bob Moog had rejected.

This comprised a pair of oscillators, a diode ladder low-pass filter (which sidestepped Moog's patent on his transistor ladder filter) two LFOs, and a single contour generator. It was, as proposed, an integrated synthesiser that players could program and use without resorting to a spaghetti junction of patch leads.

With its sturdy wooden case, well-designed control panel and four-octave keyboard, the Sonic V should have been a huge success. Unfortunately, it wasn't. But Waytena was no mug, and he knew why... he realised that, without a recognised name to stick on the nameplate, he was going to sell very few synths*. At this point, fate - or, more accurately, incompetence - stepped in.

*And you thought that designer labels were a recent phenomenon?

Back in Trumansburg, not everything in the synthesiser garden was rosy. Bob Moog's engineering credentials may have been of the highest order, but his business acumen was not. Despite the explosion of interest in electronic music fuelled by innumerable, ghastly 'Moog' records in 1969, R A Moog Inc. was insolvent. By the end of 1970, the company had an empty order book, and there was significant competition in the shape of ARP, whose synthesisers offered significant advantages over the equivalent Moog instruments. Furthermore, Bob Moog had sunk large sums of money into one-off experiments, and seemed uninterested in the practicalities of running the business. Something had to change and, when Waytena discovered that Moog's company, and therefore the Moog name itself, was up for grabs, all the pieces of the jigsaw fell into place.

Waytena was an entrepreneur, a specialist at revitalising bankrupt or insolvent companies and then selling them for a profit. So he bought R A Moog Inc. for the cost of its debts ($250,000) and moved the company to a converted gelatine factory in Buffalo, a city near the Canadian border in upstate New York. Moog hated the place, but that didn't stop Waytena from merging his two synthesiser companies there to create Moog/muSonics, an entity that soon metamorphosed into Moog Music.

At this point, let's spare a thought for poor ol' Gene Zumchak. Having fallen out with Bob Moog once before, he again found himself working alongside the man, and was forced to leave the company. You have to pity the man's ill fortune.

Despite his personal antithesis towards Zumchak, Bob Moog obviously liked his design because, once Zumchak had departed for the second time, Moog decided to take the Sonic V and turn it into a Moog product. To do so, he made just one significant change; he returned to one of the rejected 1969 drawings for the Minimoog (one that never made it, even as a prototype), and installed the Sonic V's circuitry and keyboard into this. He then added a pitchbend wheel and glissando control. The result was the Zumchak Sonic 6... oops, I mean the Moog Sonic 6.

If you look at a picture of the Sonic V, you can see that Moog made no attempt to disguise the Sonic 6's origin. Indeed, the panels and facilities of the two instruments are all but identical. In some ways I find this quite surprising, because it's an open admission that the Sonic 6 was someone else's instrument. Maybe Moog didn't care, or maybe he was happy for Zumchak to take the credit for the design; I have no idea which (if either) is true. But, as a result, the Sonic 6 looks and feels quite unlike any other Moog synthesiser. Fully integrated, with the keyboard, controls and synthesiser circuitry built into a hinged ABS case, it is perhaps unlike any other synthesiser, period. (Sure, the EMS Synthi A and AKS are also built into an ABS case, but these lacked a real keyboard so, for the purposes of this discussion, they don't count.)


When you open the case that houses the Sonic 6 you find the keyboard, performance controls, and interfaces in the lower half, with the control panel and an integrated speaker system in the upper.

The four-octave keyboard is particularly generous, making the instrument as large as a small polysynth, but it allows you to make the best use of the Sonic 6's duophony (of which more, later). To the left of this, you'll find the limited number of performance controls. Gone are the characteristic Moog dual pitch/modulation wheels, to be replaced by a single, transversely mounted pitch wheel. Above this, you'll find the master volume control and the portamento rate control. But that's all.

Behind the keyboard lie two sets of interfaces: inputs to the right and outputs to the left. The left panel offers the main output (marked "monitor") and a headphone output, together with three switches: power on/off, monitor on/off, and speaker on/off. The panel on the right provides an external signal input (with associated gain control), a generous complement of CV inputs for the pitch, filter cut-off frequency, and output gain, plus a trigger input on a Cinch-Jones socket marked "Accessory". But none of this gives you an idea about the idiosyncrasies of the Sonic 6. To appreciate these, we'll have to take a closer look at the architecture itself...

Modulators, Oscillators and other signal sources

Starting on the left of the main control panel, you'll find the Sonic 6's twin low-frequency modulators. Named WAVEFORM GEN X and WAVEFORM GEN Y, each of these offers four waveforms (sawtooth, ramp, triangle and square) plus a RATE slider used in conjunction with either a MASTER frequency control or the Contour Generator. You can program the LFOs independently, and then mix and balance their outputs using the BALANCE X/Y knob. There are few early monosynths that offer dual programmable LFOs, and even fewer that allow you dynamically to control their rates using an envelope generator... but dual, mixable, dynamic LFOs? Right now, I can think of only one: The Crumar Spirit.

Moving to the right, we come to the oscillators, called TONE GENERATOR A and TONE GENERATOR B. Each of these offers sawtooth, triangle and pulse waveforms (the last with variable pulse width, but not pulse width modulation), coarse tuning (-2 Oct, "0", and +2 Oct), and fine-tuning. Underneath the panels holding these, there are secondary panels that contain the modulation options. For Oscillator A these include modulation using the X/Y mix from the LFOs, plus the output from the contour generator. For Oscillator B the inputs are the X/Y mix from the LFOs, plus the signal from Oscillator A (thus making the Sonic 6 a 2-operator FM synth). Furthermore, Oscillator B offers keyboard scaling from 0% to 100%, thus allowing you to play in micro-tuned scales such as quarter notes, or obscure avant-garde scales such as 17- and 19- notes per octave.

But that's not all. You can select the note priority that drives Oscillator A, choosing between low note, high note, or "off". Since Oscillator B is always high-note priority, this means that you can play the Sonic 6 duophonically.

Moving another few inches to the right of the control panel, we now come to the Ring Modulator, the pink/white Noise Source, and the Source Mixer. The Ring Modulator offers two carrier inputs: Oscillator B and the external signal input. The modulator input can be either Oscillator A or the mixed X/Y output from the LFOs. Given that, at their fastest, the LFOs stray well into audio territory, this offers yet another flexible range of facilities, especially since you can use the oscillators' FM capabilities simultaneously with any of the four RM combinations available. The Mixer then allows you to mix the outputs from the oscillators (balanced using the Balance A/B control) with the output from the Ring Modulator, the Noise Source, and the untreated signal from the External Input.

As you can imagine, this is a hugely flexible package of features, and it makes the Sonic 6 a natural choice for all manner of weird sound effects and spacey noises. But let me put one myth to bed right now. I've read in numerous places, both on paper and on the web that, due to outrageous tuning instabilities, the Sonic 6 is unusable as a melodic synthesiser, and that it is useful only as a generator of weird and wacky sounds. This is a load of bovine manure. My Sonic 6 is "in tune" within seconds and, thanks to its temperature-compensated oscillator circuits, it remains so whether left on for a few minutes or a few hours. OK, I'll admit that the octave selector is slightly out on oscillator B, and that the scaling differs between "A" and "B" by perhaps 1% across all four octaves. However, this is no worse than many other vintage synths I own, and an hour spent with a small screwdriver should allow me to correct even these slight errors. Indeed, my experience of the Sonic 6 suggests that it is among the most stable and reliable of the early monosynths, which may explain why Bob Moog used one as an educational aid when he toured the lecture circuit in the mid-'70s.

The VCA and VCF

Next in the signal path, we come to the filter. Except that we don't. Unlike every other pre-patched (i.e. not a modular) synth that I know, the Sonic 6 appears to present its VCA (or 'ARTICULATOR') before its VCF. If you think about it, there's no reason why this should not be a viable configuration, but it looks damn weird!

The VCA offers two signal paths... one whose gain is controlled by the Contour Generator, plus a switchable Bypass that appears to pass all the signal from the Source Mixer directly to the filter.

The Contour Generator itself is, however, the great weakness of the Sonic 6. There are only two controllable stages - Attack and Decay (which would, in normal parlance, be called Attack and Release) - plus a two-position switch that selects between an AR envelope and an ASR 'trapezoid' shape. Given the Sonic 6's huge range of modulation capabilities, and the number of envelope destinations, you have every right to expect at least two full ADSR generators, but there it is... we've identified the Sonic 6's Achilles heel.

Underneath the Contour Generator panel, you'll find the Trigger Input selectors, which offer keyboard triggering, and GEN X and GEN Y triggering (which operate regardless of the LFO waveforms selected). You can select and mix any combination of these to create strange polyrhythmic effects. That's nice. Unfortunately, once triggered, the Contour Generator will always complete its cycle, even when set only to Keyboard Triggering, and whether you hold a key or not. Sometimes useful for percussion synthesis, this can be a complete pain in the posterior when you use sounds that have a slow attack. You release the key, expecting the sound to enter its Release stage but it continues to swell, possibly in both volume and brightness. That's not nice.

Penultimately, we come to the filter. Early Sonic 6s retained Zumchak's diode ladder filter, but serial numbers above 1264 incorporated Moog's transistor ladder. Either way, the panel offered the usual control over the cut-off frequency and resonance, with cut-off frequency modulation provided by the Contour Generator, the mixed X/Y output, and/or the keyboard (0% or 100%).

At maximum resonance, the filter will self-oscillate. However, on my unit (serial number 1496) the Moog filter offers progressively less resonance at lower frequencies, to the point at which self-oscillation is no longer possible. This behaviour emulates that of my Minimoog, although to a more extreme degree. You should not be surprised by this similarity... after all, this is one of the Sonic 6s with the traditional Moog filter.

The final 'panel' contains the Direct Output Mixer. This allows you to mix the untreated output from Oscillator A, Oscillator B, and the Ring Modulator directly into the final output. Since these signals are not modified or articulated by the VCA or VCF, they offer quite different tones to those provided by the conventional signal path. Indeed, if you base the main synthesised sound just on Oscillator B, and then added low-note priority Oscillator A in the Direct path, you can not only play duophonically, but (within limits) duotimbrally. This was amazing stuff in 1972.

In use

In addition to its weird architecture, the Sonic 6 hides a few tricks that you probably won't discover when you first play one. My favourite involves the GEN X/Y Balance control. As already described, this balances the outputs from the two LFOs prior to applying the summed CV to the oscillators, Ring Modulator, and filter cut-off frequency. What is not apparent, however, is that if you turn this knob fully anticlockwise and click it "OFF", GEN X is directed exclusively to Oscillator A and the filter, while GEN Y is directed exclusively to Oscillator B. This is fantastic, allowing you to control the depth, waveform and rate of modulation independently for each oscillator. The richness of sound thus obtained has to be heard to be believed.

A second bonus concerns the implementation of the Glissando. When the keyboard tracking of Oscillator A is set to "High Note", glissando affects both oscillators equally, producing the portamento effect that you hear on almost all other monosynths. However, if you set the tracking of Oscillator A to "Low Note", glissando does not affect it. If you then play the Sonic 6 monophonically, Oscillator B glides between notes, while Oscillator A jumps directly to the new pitch. This is an uncommon effect, but very expressive.

The third bonus, for me, concerns the filter, which tracks the keyboard perfectly. When self-oscillating, it produces a gorgeous, delicate wave that is slightly more complex than a pure sine wave (and therefore more interesting) but which retains much of sonic purity and roundness of the sine. Played with a little glissando, a little vibrato, and a moderate Attack and Release contour on the VCA, this is a superb 'lead' patch, that would be perfect for much of today's New Age twiddling.

Hang on a second... if the VCA precedes the VCF, it should not be possible to articulate the self-oscillating filter. This means that that the signal flow depicted on the control panel is wrong! I can think of only one acceptable excuse for this: because the controls are mounted directly onto the synthesiser boards, it may have been necessary for electronic reasons to have the VCA components to the left of the VCF. Nevertheless, to draw the signal path incorrectly on the panel still seems irresponsible, if not downright loony!

But to concentrate on the niggles is, perhaps, to miss the point. In 1970 and in 1972, this was a remarkable design, and both the Sonic V and the Sonic 6 deserved greater recognition than they ever obtained.


When people tell the story of Moog synthesisers, there are many names that appear time and again. There's Bob Moog himself, of course. You're also likely to hear the names of Tom Rhea, Dave Van Koevering, and Bill Waytena (who almost certainly saved Moog from extinction). And, if you're researching the development of the Minimoog, you will probably encounter the names of Jim Scott, Bill Hemsath and Chad Hunt.

But what of Gene Zumchak? How many of us can hold our hands up and say that we fully appreciate his contribution to synthesis? Not many, that's for sure.

This is not surprising; Bob Moog doesn't even mention Zumchak's name when interviewed for reference books such as Mark Vail's highly regarded "Vintage Synthesisers". Neither does Peter Forrest in his excellent "A to Z of Analogue Synthesisers". Forrest merely says, "Whoever designed the Sonic V deserves praise: one of the earliest portable synths, it was good enough to avoid major reworking when Moog turned it into the Sonic Six". Yet it was Zumchak who - before the development of the Minimoog - hassled Moog repeatedly to design an integrated synthesiser. It was Zumchak who designed the Sonic V (and therefore the Sonic 6), and it was Zumchak who introduced the uA726 chip that Moog Music later adopted for its own oscillators. Likewise, Zumchak's contribution to duophony seems to have been forgotten.

So when we tell the story of Moog synthesisers - indeed, when we tell the story of all analogue synthesisers - I reckon that we should talk a little bit less about Bob Moog, a little bit less about ladder filters and modular synthesisers, and somewhat more about Gene Zumchak. Wherever you are now, Gene... well done, and thank you.

You can find my full review of the Moog Sonic 6 in Sound On Sound magazine, March 2002.

Copyright (c) 2002, Gordon Reid.

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