Buchla Music Easel

Photo: Tim Rafferty

Fifty years after Don Buchla first released his portable electronic music studio, is the world finally ready for the Music Easel?

The development of synthesizers into the myriad forms we know today can be traced back to the 1960s and two American designers, one whose name became synonymous with ’synthesizer’, the other who thought the word was too limiting for his instruments. The two men are, of course, Bob Moog and Don Buchla and both leave legacies far greater than implied by terms such as East Coast or West Coast Synthesis. Although it’s true they were geographically separated, Moog and Buchla invite as many comparisons as contrasts, but there’s no denying that Moog’s impact has been the most keenly felt across the industry. Even to this day, Don Buchla remains a much more elusive character, his contributions less widely understood and appreciated.

While I can’t hope to redress the balance in just a few thousand words here, I would like the opportunity to dally in the Buchla universe and check out a recently reissued classic, the Buchla Music Easel. Born out of the artistic melting pot that was the San Fransisco Tape Music Center, this was an electronic instrument designed for portability, patchability and live performance. It seems criminal that it’s not as well known and loved as the Minimoog, ARP 2600 or Synthi AKS.

Around eight years ago, having long been curious about Buchla and his instruments, I treated myself to an Easel — as a kind of retirement present. For reasons I’ll come to later, it was eventually returned, but I’ve always regarded it as the missing link in my personal quest to learn about every important synth. Without giving away too many spoilers, much has changed since then, not least that the Easel is now available in two updated versions: Retro and Modern.

First Steps

Drawing from modules Buchla had already designed, the Music Easel first appeared in 1972. While the bulk of this review will concentrate on the more feature‑rich Modern version, both it and the Retro have the same long pedigree — and have been given enhancements to extend their life far into the future. Both models are supplied in robust cases, ideal for the performing musician.

The Music Easel Modern comes in a squarer box and adds the EMBIO (Electronic Music Box I/O) module.

Upon connecting the external laptop‑style power supply, you’ll probably need to reach for the Quick Start patch sheet (unless you’re already up to speed on the Buchla way). Disappointingly, a full printed manual is not supplied. Indeed, you have to assemble its components yourself from resources on the Buchla website. Accordingly, to supplement the original 1974 ‘Operating Directive’, I added the 208c addendum, the 218e V3 user guide and the EMBIO manual. Incidentally, all the components of the Modern Easel (which I’ll refer to as simply Easel from now on) are available individually. The 208c or Easel Command is the main instrument, the 218e the updated keyboard and the EMBIO is the ‘Electric Music Box I/O’.

Ten banana cables are supplied, along with four shorting bars, a MIDI adaptor (Type‑A) and a TiniJax lead. This lead closely resembles a 3.5mm mini‑jack lead, but it’s not; it’s a fraction wider at 3.58mm. Before making any assumptions, it’s therefore worth taking stock of the sockets strewn about the panel, ready to baffle then hopefully delight.

Starting with the EMBIO, its CV and gate connections are 3.5mm, ready to talk to Eurorack. MIDI is present in TRS mini‑jack form and there’s another mini‑jack located on the 208c, the headphone output. Every other small jack, including the mixer on the EMBIO and the audio outputs on the 208c, are in the archaic TiniJax format — because that’s how Buchla have always done it. It would have been nice if they were more obviously different because, as you can imagine, it makes things slightly awkward when interfacing with non‑Buchla gear or when using the external audio input. I’m told TipTop’s stackable Eurorack cables work reliably in both types but haven’t tried them personally. There are a couple of USB‑C connections (also for MIDI), and the audio outputs and sustain input are reassuringly normal quarter‑inch. Everything else is, well... bananas.

The Easel is mostly modular in concept; there are some hard‑wired connections and a multitude of switches, but you won’t get far without patching. In a Buchla system, this means banana cables, which have one advantage over Eurorack (and 5U format) in being naturally stackable. Multiples are not required. The cables are colour‑coded for length and the sockets coloured by function, with black denoting a CV input and various hues representing the available modulation sources. Furthermore, pulse outputs, which are used for timing information, envelope triggering and so on are red, making it easy to see your options at a glance.

Unlike Moog, Buchla preferred to keep audio and voltage connections separate, considering the differences as ‘sound versus structure’. Thus, bananas carry control signals (0‑10 V) with shielded cables reserved for audio. One small exception is found in the Quick Start patch but we’ll leave that as a treat for later.

I should mention that the banana sockets are all pretty tight at first and tough to disconnect one‑handed, at least for this puny, partially retired knob‑twiddler. Fortunately, they do loosen up after about a week of regular use and, long‑term, I suspect they’ll prove more trustworthy than, say, Eurorack connections.

The Retro version of the Music Easel keeps things aesthetically closer to the original.

The Eclectic Electric Music Box

The Easel is a collection of tools assembled to serve electronic musicians from the tape music era — and beyond. Central to operations are two oscillators, the Complex Oscillator and Modulation Oscillator, the former notable for its wavefolding. The latter is a modulator in either low or high frequency ranges as well as being an audio source in its own right. In supporting roles are a voltage‑controlled envelope, a ‘Pulser’, a five‑step sequencer, a source of random voltages, two low‑pass gates, white noise and a spring reverb. Additionally, there’s a voltage inverter and an audio input (with envelope follower), plus a Program Interface slot. Volume controls for the two channels and a headphone output round things off.

Courtesy of the 218e keyboard, the Easel gains portamento, an arpeggiator, four assignable voltage sources and several control outputs. While both Retro and Modern Easels include MIDI, only the Modern’s EMBIO provides those handy CV and gate inputs, along with a set of extra utilities.

The Easel is one of those rare vintage synths capable of patch storage and recall. Thanks to voltage control and the Program Interface slot, prepared cards could be inserted and even hot‑swapped during performance, invoking radical shifts at the flick of a switch! That option still remains, but if you purchase the Program Manager, it will provide a solder‑free alternative, one which is supported by an app for Mac and Windows.

What, No Cutoff Knob?

The central playground of the 208c is a feast of helpfully coloured and responsive sliders. Admittedly, an over‑stacked banana can sometimes get in the way, but that’s where those shorting bars come in handy — for connecting common source and destination pairs without impeding access. Typically, the sliders are divided into two types, one providing direct access, the other for voltage control via an adjacent CV input. In the case of the Dual Lo Pass gate (LPG), raising the Level 1 or 2 sliders will open the gate and produce a drone. If you’ve played an ARP Odyssey or other synth with a VCA gain control, this will be familiar.

Before plunging in, it’s worth adjusting to the clean, raw tonality on offer. For those of us who grew up with synths from Roland, Korg and Moog, the Easel hints at an alternate reality, one in which filter cutoff and resonance don’t take centre stage.

Actually, the Easel does have filters — two of them; they’re components of the Dual Lo Pass Gate — but they behave rather differently to the low‑pass filters we’re used to. And, actually, the Lo Pass Gate module included isn’t even the one Buchla want us to have...

The tale goes like this: Easels sold today via the UK distributors are shipped with a Lo Pass Gate module that is fully RoHS compliant, meaning all its components can be legally tossed into landfill(!). However, Buchla’s standard vactrol is not RoHS compliant because it contains a very tiny amount of cadmium. And while it’s perfectly legal to buy an Easel direct from the USA, I suspect most of us would rather avoid the import process. Anticipating this, Buchla have decided to offer the ‘proper’ LPG free of charge, dispatched directly to the user. I duly requested one and, after a wait of just a few days, it arrived and I popped it in.

To my ears, the replacement LPG is an instant, audible improvement, one that new Easel owners should definitely make the effort to obtain. If you were ever curious about the famed ‘Buchla Bongo’ sound — the result of a very short envelope pinging a Lo Pass Gate — then you absolutely need the real thing. Substitutes do not cut it.

Via switches, you select the mode for each LPG channel, choosing either a (non‑resonant) 12dB/octave low‑pass filter, a VCA or a combination of both. It’s this Combination Mode — filter plus VCA — that produces the pleasing effect we’ve come to associate with vactrols. The resistance of these opto‑electric circuits depends on the measurement of light from an LED — a response sometimes described as ‘sluggish’. More importantly in this context, fast hits in succession translate to an accumulated brightness. The results feel somehow alive, or maybe suggestive of an acoustic instrument.

The second gate may be fed by the Modulation Oscillator, the aux in or the first LPG output. If no connection is made at the aux input, a white noise source is helpfully normalled in. Finally, while the Easel doesn’t have a high‑pass filter, routing the first LPG into the second produces some rather nasal, phase‑cancellation type effects.

Further Into The 208c

The Complex Oscillator and its wavefolding are key elements in the Easel’s sonic footprint. The process of flipping parts of simple waveforms to create new shapes has become better known in recent years, thanks to various Eurorack modules and standalone synths from Make Noise, Arturia and even Moog. Raising the timbre slider gradually warps the oscillator’s plain sine wave, turning it increasingly raspy and gnarly. If you sweep the fold amount with an envelope, it releases a rich seam of hard, biting tones. For extra depth, the sine can be mixed with a second waveform — either a thin pulse, a square or a triangle — and the mix modulated in a subtle, almost PWM way.

Moving on, the Modulation Oscillator might initially seem like the poor relation. After all, it lacks wavefolding and offers just a simple selection of sawtooth, square or triangle waves. Fortunately, these new Easels have a little extra something — as revealed in the Quick Start patch. There, the TiniJax cable is employed to patch the Complex Oscillator’s (audio) output to the Mod Oscillator’s FM input. And while it might seem contrary to the Buchla ethos, this bonus flavour of FM is well worth having.

As its name suggests, the Modulation Oscillator also provides a source of audio‑rate modulation. Working together, the oscillators conspire to produce analogue FM and ring‑modulation that wouldn’t sound out of place on classic Radiophonic Workshop soundtracks. You can apply AM to external signals too, an option I recommend even if you only have loose mini‑jack leads to hand. My first choice was to draft in a drum machine, because percussion’s clear transients are ideal for testing envelope followers. Then, by applying low levels of AM, a humble Korg Volca was transformed — Cluster‑style — by tremolo, while high AM levels yielded crunchy ring‑mod grooves. If at this point you were to patch the envelope follower to an LPG or oscillator, you might not emerge from your lair in time for tea!

In its Lo mode, the Modulation Oscillator behaves like a regular LFO, especially if you disengage the keyboard tracking. In the Modern Easel, a second LFO is available via the EMBIO, and it’s one characterised by its slowness (around 30 seconds at the lowest rate). So, while it’s never quite fast enough for vibrato, not even the wavery Boards Of Canada variety, this LFO can supply welcome life and movement to just about any parameter.

Positioned to the left of the oscillators, the envelope suits a right‑hander who’s forever adjusting note shape while playing (eg. me). The envelope is comprised of three stages — attack, sustain and decay — with switches to determine the mode and source. Unusually, it needn’t be triggered exclusively by the keyboard — the Pulser or the sequencer can serve instead. Its versatility is further extended by voltage control of each stage, and by the choice of sustained, transient or looping operation. When looping, the decay value sets the speed of repeats.

The adjacent Pulser is a decaying sawtooth that can function either as a trigger source or a basic envelope. It, too, offers transient or sustained modes, so it can remain on during a keypress. A small button will manually start it and, in self‑triggering mode, the Period slider sets the loop speed. This, naturally, is voltage‑controllable.

If we rope in the EMBIO’s Slew processor, the Pulser becomes a quite different animal. By slewing the start and end phases of a control signal separately, you can soften the Pulser’s otherwise instant attack and/or blur its release. And thanks to the stacking power of banana cables, you never lose access to the raw Pulser output, so, at times, it seems like you’ve got three envelopes.

Most of the coloured CV outputs are identical copies of each other, distributed around the panel for convenience. However, this is not the case for the Random Voltage source, which generates a unique random value at each of its four outputs. You’re therefore free to exploit the many possibilities this presents, with new values created for every trigger of the keyboard, Pulser or sequencer.

It’s easy to be dismissive of a mere five‑step analogue sequencer, given the ubiquity of eight or 16 steps in classic sequences and bass lines. But this is a timely reminder that sequencers are also useful voltage sources with a variety of uses. For example, when driven by the keyboard, this one can supply accents, stepped timbral changes, variations in envelope length and more. And, given that panel space is finite, Buchla deserve kudos for choosing five rather than four stages.

Switches above each slider play their part when the sequencer is used as a trigger source. It offers the possibility of triggers that occur only on every other note, or in other patterns within the five‑step limit. Sequence length may be set by switch or CV.

Finally, a single knob is provided for the spring reverb — a splendid‑sounding example of the species with a range stretching from completely dry to a dense, reverb‑only mulch.

The 218e

Once upon a time, I tried and failed to get the older keyboard model to work reliably, so I’m very relieved to find the 218e a massive improvement in responsiveness. Indeed, I have yet to resort to the supplied earth cable, worry about what type of slippers I’m wearing or blame my weed‑infused carpet for the static it generates.

A somewhat avant‑garde musician himself, Don Buchla was a keen advocate for innovative controllers, preferring them to conventional musical keyboards. Nevertheless, the ‘almost normal’ 218e is a pleasant alternative to regular keys and, at just under 2.5 octaves, is fast and fun to play. If necessary, it can serve as a MIDI controller and is even fitted with pressure and velocity outputs.

In case you were wondering, keyboard pressure is generated by measuring the surface area of finger in contact, whereas velocity is a product of finger speed. Admittedly, there’s not a massive range of either available but, via calibration routines detailed in the user guide, pressure sensitivity can be tailored to distinguish between light finger‑tip contact and a more full‑on press. Similar routines fine‑tune the velocity response, add slew to the pitch Strip and generally make the Easel your own.

The four Preset Voltage Sources are invaluable for numerous roles throughout the Easel and even within the 218e itself. They can supply favourite portamento amounts, quirky pitch transpositions or specific arpeggiator speeds. And in another user customisation, the fourth knob can be assigned to octave transposition, and over a wider range than is otherwise possible.

New to this keyboard, the Strip is a convenient source of pitch‑bend and finger‑wobbly vibrato. For each contact, a pulse output is generated, which is useful for actions such as triggering the envelope or stepping the arpeggiator.

Dedicated controls supported by a few hidden powers bestow a wider appeal on the arpeggiator than its simple ‘up’ and ‘random’ directions promise. It can be latched with a sustain pedal or a long press of two buttons and earns bonus points by including random velocity variations. When cranked to maximum speed, the arpeggiator can go very fast indeed, turning the Easel’s output into a shimmering wall of sound. For added complexity, it can be paired with the step sequencer or Pulser, and external synchronisation is available from the pulse input or MIDI Clock. Finally, another user configuration option, ‘directed random’, uses the Preset Voltage Sources to fluidly switch between up and down or descending random motions.

Retro & Modern

The larger of the two models, the Modern Easel (58cm x 39cm x 16cm) is housed in a hard black plastic suitcase with a blanking panel indicating its capacity to house an extra module. The Retro has an even more solid aluminium case (55 x 42 x 15cm) as well as old‑style knobs, but it sacrifices the EMBIO, additional module space and the CV/gate inputs. Otherwise it has all the enhancements of the modern 208c and 218e.

It’s OK to want a Music Easel just for the cool Buchla branded case.

Although I’ve mentioned the EMBIO throughout the review, there are still a few points about it worth making. The first is that the slew knobs were rather wobbly, evoking memories of my earlier, less satisfying Easel encounter. The second is that its CV mixer is wonderful. The primary CV input can be attenuated and/or inverted and the crossfader (complete with CV input) facilitates patching marvels such as velocity‑driven envelopes, the morphing of CV sources and much more. Lastly, I should briefly draw your attention to the CV to pulse converter. From triangle or sawtooth input, it generates a square/pulse wave suitable for clocking and triggering operations.

Conclusion

It’s been a real pleasure to once again spend time with a Buchla Easel and ponder its place in the grand scheme of things. My overwhelming impression is of an instrument that inspires you to think and work differently — and maybe even to revise your approach to analogue synthesis.

Buchla have succeeded admirably, refining features and boosting flexibility without compromising the essential Easel nature.

It’s always a challenge, updating classic gear without breaking what made it classic in the first place, but in this respect Buchla have succeeded admirably, refining features and boosting flexibility without compromising the essential Easel nature. It also looks strikingly attractive and is one of those instruments that just sounds great, even in relatively simple patches.

In a recent book about the Minimoog, many users agreed it was ‘good for bass’, but I doubt there would be such a broad consensus for the Easel, which is more open‑ended and therefore harder to pin down. Yes, it happily delivers bells, basses and buttery solos, but there’s no denying its gravitational pull towards the experimental and weird. If you’re curious about just how ‘out there’ it can get, it’s well worth trawling YouTube for self‑playing instances of the ‘Krell patch’.

Compared to the Easel I bought some years ago, these updated models have been a delight and I’m really going to miss them. Finished to a much higher standard and with a keyboard that actually works, so many of the issues I experienced have finally been laid to rest. And while this is obviously not a budget instrument, neither were the reissues of the Minimoog or ARP 2600. Ultimately, both of the new Easels are a fitting tribute to Don Buchla. Old designs they might be but they still hint at fresh and untapped possibilities, which isn’t bad for an electronic music box from the 1970s!