Electric Music Box

This is my instrument, mainly equipped with contemporary clones of the Buchla 200 series (Bj. 1970-82). The low count of Buchla-modules (e.g. in comparison to Eurorack and MOTM) appears as being rather limited (almost like a de-individualization), nevertheless it shows instrumental charm and unmistakable character, which however isn't limited to a sound.

Clones do have the advantage of not being 45 years old and are considerably less expensive compared to the very rare originals. In some cases even defects or weaknesses have been corrected. How the differences to the originals are in detail, I can't judge, but I am extremely happy with these modules.

Buchla Modular Series are roughly divided into the 100-Series (60s), 200-Series (70s) and 200-e-Series (since 2005). In the 80s there also were the 400- and 700-Series, which are however extremely rare.

One point why these modules are so interesting and different is, among other things, the fact that mixing (audio) takes a "different rank". Most functions are designed for adjustable weights. Also, very beautiful distortions are produced - almost an extension of the Waveshaping, the other Buchla specialty. Very intuitive.

I've owned many synths - none of them has tied me like this.

Don Buchla


  • With this format I'd like to begin with the person Don Buchla (1937-2016). He is (for me) one of the “Big Four”, which are Don Buchla, Peter Zinovieff (EMS), Robert Moog und Alan R. Perlman (ARP) - they might have appeared on the scene also in this order (ca. 1960-70). I think, all four had assistance of important coworkers, whose existence shouldn't be unmentioned. Such things are developed in dialogs.

    Don Buchla always appeared early with his developments - the modular 100 series was e.g. already introduced in 1963/64 (picture on the left/with the Maestro - photographer unknown). For several reasons the company had never achieved the “commercial break-through”, which surely has to do with the fact that Moog and ARP found a wider group of customers in Rock and Pop music particularly with smaller stage-synthesizers, while Buchla operated with composers and universities, which required completely different conditions/biases. Furthermore, synthesizers were already expensive, Buchla however was very, very expensive. Since Don Buchla, the eponym and creator of this format, perceived the term “synthesizer” as misleading, he called his instruments “Electric Music box”.

    The instrument behaves amazingly similar (LPGs) to an acoustic instrument and is very pleasant and intuitive to control. The module panels layout was often designed first at Buchla, which is very unusual. The size of the modules (4U), the functional density, the physical distances between the controllers and the arrangement of the switches / controllers are the most successful for me (compared to other formats). The intuitive access is additionally supported by the striking arrangement and the easily distinguishable appearance of the modules. Because of the different layout (Waveshaping/LPG) and the California origin, the term “Westcoast” established for these instruments.

Buchla 200-e

The current Series

    A very nice system - unfortunately not cheap: the pictured Case (18U) costs depending on the configuration from $ 22.000.- (configurations are possible up to more than 30.000). A very adored instrument! Derived from the options almost without competition. I have little experience with this system and can only describe my onetime "experience" - it wasn't that positively, but the report still includes "neutral" information on the System 200e.

    In spring 2012 I wanted to start with a Buchla instrument - but with the e-Series. After trying a Skylab (10U) no joy came into existence. Processing seemed suspect, many knobs felt very shaky. 2 of the 10 modules did not work, i didn't like the sound of the 261e (compared to the previous series' oscillators) and unfortunately it was the only built-in VCO.

    But above all, the (quite interesting and unique) Preset Management is in my way, because I just want to do this with Max. It would be a completely controlled sub-level that would bring only more complications to my work, I would also like to avoid modules with firmware. The e-Series is also highly adapted to the Random and Sequencer Pulse-world, witch is quite far away from what i would like to do. There are much more Pulse I/O's in the e-Series, as in the precursors - they are also used for calling up Sub-Presets directly in the modules. In the Triple Morphing Filter 291e are e.g. 3 "Nodes", each with 8 "Stage Numbers". That is an integrated Step Sequencer with 8 steps and 3 buses which is used for storing the 3 Filter Values. With Pulse it is "stepped" and with CV interpolated (I think it's interpolation and not morphing). Again - this I want to do with Max/Computer.

    The e-Series has grown in terms of performance and compressed in size at the same time (compared to the 200 series). The Dual BPF 291 has become a Triple Morphing Filter 291e. The System Interface 227e has shrunk and still offers additional options (the only e-module in my system). A highlight (for me) is the Matrix-Router, but (fortunately) probably i do not need it.

    So - a great concept - but not for me. Maybe someday more e-Series will show up in my system but i prefer building my base system on the basis of the 200 clones, which I also prefer sonically.

    [edit 2019] Meanwhile, the company is in other hands and very well staffed. For future and quality it looks much better now.


  • Buchla modules (4U) make no synthesizer but an Electric Music Box. Since Don Buchla did not consider keyboards as ideal controllers, there were alternative control modules from the beginning - for CV, there were different Touch-Plate Attenuator variants and very individual Sequencers, for audio more complex Matrix Mixers.

    The Audio Connector Format is the rare Tini-Jax .141 from Switchcraft. Tini-Jax is minimally larger than 3.5mm Mini-Jack and looks similar to the confounding. Tini-Jax plugs are available in metal and plastic versions.

    Mini-Jacks do not sit quite so firmly, but function also and can therefore be used without hesitation on the Buchla.

    Buchla uses Line Level 0dB/600 ohms for Audio (instead of +12dB/150 ohms, like Eurorack).

    Buchla uses 1.2V/oct (instead of V/oct or Hz/V).

    Buchla Electric Music Boxes work internally with 15V - even if they are supplied with 12V power supplies! The original 100-Series and the very early 200 modules were still supplied with 15V (and partly more).

    The Banana Sockets are subject to a color code. Orange for Pulse Inputs and red for Pulse Outputs, black and gray for CV-Inputs, blue and violet for CV-Outputs.

    The alternatives (Gray/IN and Violet/OUT) are only used when inputs or outputs are in a large number in the module.

    In the 200e series, the buttons are color coded too: the positions of the blue buttons are stored in the preset - the white not.

    A particular peculiarity is the length and strength of the Pulses. The modules (especially in the 200e series) produce very different pulses with different shapes (rectangle/triangle), lengths (0.5ms to 4ms) and strengths (9-14V). I'll go back to this (see: BUCHLA peculiarities in the CV control by other formats).

    Buchla - buchla.com

    Buchla 200 Series - electricmusicbox.com

    Buchla - all Series - encyclotronic.com

My Buchla

200 Series Clones
  • Since I prefer the (historical) "200 Series" and the Programming Environment "Max/MSP" is of central importance for me, I skip a large area of modules. Especially in the e-series this area plays a central role (e.g. sequencer, touch panel, matrix router and preset management).

    The modules are undoubtedly interesting - but not for me. I want to do these things with Max. So even if these modules are attractive for as many Buchla friends as possible, or are the reason for choosing Buchla - I have no ambitions whatsoever to acquire them and will report only on the details of my instrument in the following. I will discuss the computer connection (Audio to CV) here: My hybrid modular synthesizer.

    The Eurorack modules (mainly Expert Sleepers [Audio to CV]) are located underneath the upper Buchla-Boat. Power and ES-40 (SPDIF I/O) are placed on the rear, because I don't need them for playing. These are "valuable" 10HP, which also make it possible to maintain the low height of 8HP for the Eurorack "strip" in front.". Besides the Expert Sleepers modules there are Pedal Interface (sustain and expression), Dual VCA and Gate-to-Pulse Converter. In addition, there is a mini-case with two Vector Mixers (joysticks), which are connected to the instrument via two Ethernet audio multicore cables. Of course the Eurorack modules have their own power supply.


  • Programmable Complex Waveform Generator Model 259

    The "Programmable Complex Waveform Generator Model 259" (left) is a Dual Oscillator with Timbre Modulation.

    In particular, the 259 makes clear why Buchla needs fewer modules. Of course, the circuits are also possible in other formats - but they require 3-8 modules for the same tasks (ie 2x VCOs, VCAs, Attenuators, Waveshaper etc.). The division of Shaping into Timbre and Harmonics with Order and Symmetry came only with the Model 259 and makes this Waveform Generator a truly royal module. The Banana CV-Out of the left Oscillator is another advantage of the 259.

    Buchla VCO's are designed for Frequency Modulation and Waveshapping, and Buchla is arranged "differently" - also modular, but the groupings of the functions are combined in selected combinations in such a way that a basic instrumental characteristic arises.

    Dual Oscillator Model 258 and Model 258v

    The "Dual Oscillator 258" (right) is perhaps "the" classic Buchla VCO. The upper Oscillator is Sine to Sawtooth, the lower Sine to Rectangle. Model 258 has at least three Clone versions, the Model 258r, the Model 258r with historic components and the Model 258v, by Mark Verbos. I own the two last-mentioned variations, which, in all diversity, both have their merits. The Model 258v has CV inputs in place instead of the "Fine Tuning" axes. My favorite is the model with the historic components, because it is somewhat "eggier". ;-)

    What fascinates me about this Double Oscillator is how immensely "straight forward" it is. It raises no questions, has clear playing fields (top sawtooth / bottom rectangle), allows cross modulation and sounds just like the "VCO for the island".

    Harmonic Oscillator Model 262v

    The "Harmonic Oscillator Model 262v" (left) is an additional oscillator with 10 Partial Tones. Apart from the single Outs of the Partial Tones, it (of course) also has a mix output for all Partial Tones. At least Saw, Tri, Square and Pulse have dedicated outputs. The Volume of the Partials can be controlled with the sliders or via CV Inputs (black).

    Since Mark Verbos now has a well-known Eurorack series, in which there is also a Harmonic Oscillator, many will ask where the differences lie. Obvious are the two additional sliders on the 262v. They are not just two sliders: they are two important overtones that extend the harmonic spectrum considerably, because they go beyond the octave (and thus over the "triad characteristic).

    The 262v is better controllable (the Eurorack module is somewhat obscure) and the Euro VCO is based on the Model 258 Oscillator, while the 262v is based on the Model 259 Oscillator. Well - and Euro is 12V.

    Dual Sine-Sawtooth Generator Model 158

    This Double VCO is the replica of the 100 Series (1963-70) Oscillator, the "Dual Sine-Sawtooth Generator 158" - the predecessor of the 258. The 100 Series always appealed to me because of its crudity. The replica does not attain this entirely, but has other advantages, e.g. a much better tuning stability. Also, the 100 Series is not as completely CV-controlled as the 200 Series and therefore needs to be operated more manually. Oscillator 158 is just as straightforward as its successor, but has only the Sine and Sawtooth waveforms, while the 258 provides one Saw to Sine and one Sine to Rectangle. The 158 Oscillator is just wonderful and I do not want to do without it. 158 and 258 have the "famous" Buchla trembling. I like that. Sounds like the big time of electronic music.

    Quad LoPass Gate Model 292c

    Filters do not have the central position, as with VCO/VCF/VCA/ADSR "Eastcoast" systems (Moog, ARP). There are still some. The reason for the less central importance of the Filters is mainly due to two things: firstly, the Waveshaping is to be regarded as an alternative to filtering and Buchla works with Lowpass Gates instead of VCA's - this creates "more natural" ins and outs - overtones change with the volume (or opening of the LPG). Therefore, I would call the LowPassGate 292 as the "typical" Buchla module - it also visually stands out clearly by the diagonally arranged buttons.

    LowPassGates are, technically speaking, VCFA - whereby Filters and Amplifiers are controlled coupled. The module also offers a VCA and a Combo Mode. In the Lopass-Modes, the 292 is one of the most sonorous modules and is highly responsible for the "Buchla sound". At the 292, it is also time to mention the weaknesses, since some applications may require a workaround: the 292 does not completely close and should therefore be lengthened by a Gate or another VCA. Another "weakness" that is perceived as an award, is the Vactrol control: it works through optical resistors and is quite slow.

    Dual Voltage Controlled Filter Model 291

    Model 291 (right) is a Double Bandpass Filter and it's not for everyone. It is very characteristic, therefore easy to recognize and it sounds "very old-fashioned". Such pure / exclusive bandpass filters were the first filters used in electronic music (e.g., the Maihak W49 radio play distortors from the 1950s). Pure bandpass filters are rare today and are usually only part of a "variable state filter". If high and low pass are coupled, they also produce a bandpass. The Vactrol control (light source and optical resistance) of the Model 291 also creates the very own character. Lightguides are rather slower, contrary to the assumption. Vactrol controls have a noticeable inertia.

    Frequency Shifter Balanced Modulator Model 285

    The Model 285 is Frequency Shifter and Ring Modulator. This combination is obvious because for Shifting the waveform is halved and only the positve values are heard. By increasing the offset-voltage the pitch raises (Shift). By connecting the negative wave component, the "counter-oscillation" comes into play and the Ring Modulation effect is generated. I call it effect, because it does not quite correspond to a "typical" Ring Modulation - it remains more to Ring-Mix.

    There are two models of the 285 Clone. The more common model is digital - recognizable by the 4th power cable, which carries 5V and it is probably a reprogrammed chip of the TipTop Audio Z-DSP. I am not convinced by the sound of this module and think that both shifting and ring modulation with Max / MSP sound much better. Above all, this module does not generate low frequencies.

    Much better sounds the quite rare, fully analogue version of the module (sometimes called V2), which looks identical when installed. The analog module is more densely populated and has one more pcb - there are 27 trimmers - I haven't seen anything like it before. I am glad to own this module - I was on the verge of taking the digital 285 out of the instrument without replacement. Many "Buchla people" don't even know that this (analogue) module exists - the quantum difference of these modules isn't discussed very and the analog module loses - mainly because of the significantly higher costs and the much more complex setting (27 trimmers!). I don't regret buying it.

    Programmable Spectral Processor Model 296

    The Model 296 can be used as a Filterbank or, as the name "Programmable Spectral Processor" suggests, in a variety of ways for "audio processing". Actually, the 296 accommodates three modules. The sliders are exclusively connected with the function as a Filterbank. The corresponding outputs are in the middle. Soundwise the most interesting part is the "Programmed Spectrum" area - Audio Out top right. The sliders have no influence here, but the (black) CV inputs. For all 16 frequency bands, there are Envelope Follower CV Outs (blue/violet) and individual Audio Outputs. Almost as an addition I see the Comb Filter - Output in the upper left. The combination of the functions, I/O's and the distribution of the Audio Inputs in "Even" and "Odd" (2x8) also allow a Vocoder-like use of the 296 - that is precisely the Spectral Processing.

    The Model 296 also makes it very clear why Buchla is well suited to work in conjunction with computers, tapes or instruments (the line audio levels are also very beneficial). Buchla modules have the inputs usually located at the bottom and the outputs at the top of the modules.

    Dual Matrix Mixer Model 205

    Even if the "Dual Matrix Mixer 205" completely contradicts my requirements - it is huge and can not be CV-controlled - I could not resist it. Each of the 10 inputs can be controlled on 4 buses. The 4 buses are each in pairs as "left" (1-5), "right" (6-10) and "all" (1-10).

    The Switches are actually Monitor Switches for an internal connection to the Model 227 (System Interface). Input 1-5 are Monitor Left and Input 6-10 are Monitor Right. I use "Monitor-Right" as an Aux output and have a Jack Output attached to the rear of the instrument. There my Pedalboard is connected with Boost, Overdrive, Fuzz, Phaser, Delay and Reverb.

    The Mixer 205 is to be looked at as a sub-mixer. It makes a much better use, especially for the Model 296 "Spectral Processor". The inputs are at the bottom, the outputs at the top, the vertical order are volume knobs for the outputs A, B, C and D.

    Signal Delay Unit Model 277

    The "Signal Delay Unit Model 277" I have for testing in my instrument. This delay is also a special module, because there was never such a thing from Buchla. If I am properly informed, it has been developed by Roman Filipov (Sputnik)! The 1/4, 1/2 and 3/4 outputs are designed to provide feedback.

    I wanted to have a Delay in the instrument to avoid a double ADDA conversion. With the TC Electronic Flashback I already have a Delay and thus also a benchmark. I'm not convinced by the sound of the Delay 277 - although it may have many followers. I think it has to do with the digital components or the programming, because both digital modules (285 and 277) in my instrument can not convince me for the same sound reasons. In everyday life, I tend to use the Pedal of my Pedalboard - also because it can be further shaped by Boost.

    Source of Uncertainty Model 266

    A particularly popular module, which is inextricably linked to the name Buchla, is the "Source of Uncertainty Model 266". This module is probably the model of most Random Generators produced today.

    From top to bottom:

    In the top row are 3x2 Noise Outputs in the steps -3dB, 0dB and +3dB. This is very "nice" and many Random Generators do not offer that. The Random in these generators is generated by White Noise. In the second row, 2x "Fluctuating Random Voltages" are output - even without being triggered. The intensity of the movement is set via the CV inputs or controls.

    The middle "Quantized Random Voltages" and "Stored Random Voltages" represent the actual Random Generator. The lower Outputs give the "main values", the upper ones a more restricted movement.

    In the bottom row is the "Integrator" (left) and bends CV from * 0.1 to * 10. On the right, an S/H unit makes the module perfect! The Pulse outputs are different: the ascending curve and the right descending curve as the trigger (On/Off).

    The Pulse inputs (Trigger) are orange, the Pulse outputs are red. The CV inputs are black and the CV outputs are blue/violet. The metallic sockets are audio jacks - here solely noise outputs.

    Quad Function Generator Model 281

    The "Quad Function Generator Model 281" (left) makes exactly what the name says: it produces four Function curves (AD) in three variations. Once as a loop (quasi LFO), once as a single AD curve on a pulse signal (trigger) and once as ASR, the Sustain as a 5V Gate behind the 10V Trigger (Pulse) is released by 0V (releasing the key) the Release curve. In the quadrature mode, two curves are combined and two, more complex curves can be generated with this module.

    Quad Voltage Processor 254v

    The "Quad Voltage Processor 254" (right) is essentially a doubled "Model 257" and has been developed by Mark Verbos. Incoming CV values can be bent and modulated here according to all rules of art. I have it to keep a little "modular feeling" in the instrument, because I send CV mainly via my Max patches from the computer. So I have 4 computer-independent benders with offset regulators that provide the autonomy of the instrument.

    Infinite Phase Shifter Model 297

    The last module I added to my instrument is the "Infinite Phase Shifter Model 297". This module is an original by Buchla and is still being built today. Nevertheless, it does not belong in the e-Series because it can't store values. This can be recognized through the original white pot caps (white = not storable). On my module I have attached the blue Rogan caps because of the uniform appearance. The blue tape (picture) covers the blue LED of the Env follower, which almost blinds you if it is not covered.

    A really well-equipped phase shifter: beside the audio input is an envelope follower to use amplitude-related values. The size of the phase is set below, at the "Phase Shift Center". In addition, the number of stages is defined and on the right a Notch Filter can be set. For stronger internal movements is the "Sweep Oscillator" whose intensity can be controlled by Depth. Last not least is the Resonance pot (for the Notch) - quite a power gain of the modulator. All parameters can also be modulated via CV inputs.

    The lower part of the module makes this phase shifter special: "Dave's Barber Shoppe" allows to create only up or down moving phases - called "barber pole effect". Variations of up and down movements are also possible. The large knob is for the velocity or as an offset control for incoming CV signals.

    System Interface Model 227e

    The only module from the current "200e Series" in my instrument is the "System Interface 227e". Mine is however optically (Pot-caps) adapted to the historical "200 Series". I preferred the current Model 227e to the historical 227 because it is only half as big and much easier to get. It also fits even better to current, digital equipment. The 227e offers a Mic-Pre with Envelope Follower, a Headphone Amplifier, a 4 in 1 Submixer and 4 Inputs and Outputs. Each Output can be separately controlled and has its own "Swirl" Generator for 4-channel movement/rotation (direction / rate / amplitude). Output 1+2 and 3+4 each have a 3-band Equalizer and Master Volume. Four Meters with 6 LEDs each indicate the Level. Although the Outputs could be easily replaced by a Max-Patch, the additional functions (Mic-Pre, Submixer, Headphones) would be very missing. Also the EQ's before the exits are welcome.

    The "System Interface 227e" also includes a breakout panel on the rear of the case. The four Outputs are available as 6,3mm TS Jacks and it has a XLR Microphone Input.


more tiny stuff


    Inch screws are always a problem in Germany. To fix the modules I have blue allen screws. They are a little longer than the Buchla screws (but shorter than in the photo), which is very good to me, because the short Buchla screws with short threads like to jump out too easily. Shipping was easy and went very fast.

    Socket Head Cap Screws - Blue


    With the 200 Series, Buchla switched from the black Davies Knobs to the blue and red Rogan Knobs. Although the black Davies Knobs look better visually and also feel better in the twisting, I, triggered by the 205 Mixer, exchanged the Davis Knobs for Rogans on all modules, except for the VCOs because the position line of the Davies is recognized incredibly badly. That "consumes" too much attention while playing. In the dense colonization of the Model 205 (with 40 Pots) also more room for the fingers remains with the Rogans, because they are not as thick as the Davies.

    The red skirted caps, as far as I know, were first taken only for Volume Control, but already on the Easel that rule was broken. (I've seen the small red pot so far only at the Easel for Fine Tuning and Waveshaping.) I have however, with my instrument, this color coding taken into account (red = Vol). It relieves and simplifies the interface!


    All these special parts are hard to come by and often the prices are astronomical! Therefore it is all the more pleasing that there is an address in Germany.

    Whether Rogan Knobs, Tiny-Jax, Boats (in different sizes!), Busboards or Patch Cables - also with Sommer Goblin cable.

    WeedyWhizz also offers parts for other formats and builds very nice cases.

    WeedyWhizz Website

  • Tini Jax

    Buchla patch cables are hard to find and very expensive. That's why I first had only Mini-Jack patch cables. Finally, I soldered myself Patch Cables with Tini Jax.

    Because I don't like the cheaper models with plastic cap 740 .141, I decided for the 780 .141 metal (shielded). Tini-Jax .141 plugs are only available from Switchcraft.

    Switchcraft Website

    Since the cable opening of the connectors is only about 5.5mm, the cable selection is somewhat restricted. My choice fell on The "Goblin" by Sommer Cable in the (moderate) colors red and ice gray. Great cable - and it fits perfectly with a shrink tube.

    Sommer Website


    Buchla likes Pomona cables - and Pomona Electronics sells the nicest Banana-patchcables. In Germany they can be purchased via Mouser oder Digikey.

    Also with the cables Buchla follows a color coding.

    Pomona-Kabel on the Digikey Website

    Pomona-Kabel on the Mouser Website

    There are also cheaper cables from other manufacturers. I recommend to choose the plug length of 15mm (there is also 17mm).

The Eurorack in my Buchla

Audio-to-CV, Foot-Control and Vector Mixer
  • To control the Buchla from Max, I use Expert-Sleepers Audio-to-CV modules, which are only available in Eurorack format. Since I built the Expansion-Boat myself, I took the chance to integrate the Eurorack discreetly (and horizontally). The power module and the ES-40 (SPDIF I/O), 10HP, are located on the rear of the instrument.

    The upper case on the picture shows the modules that are in the Buchla (including the modules on the back):

    To generate the special Buchla Pulses (4ms 10V Peak with 5V Gate) there is a Gate-to-Pulse Converter from Synovatron connected to the Gate Expander (8x Trigger/Gate) of the Expert Sleepers Block (red) . Since my instrument has hardly any Pulse inputs, I just require those 5 pulses. More about Expert-Sleepers and the Pulse-Converter below (Buchla peculiarities.

    I use the remaining 8HP on the front for a foot control module from ADDAC. An Expression- and a Sustain pedal can be connected. Next to it is a µVeils Dual VCA for the "Mix" outputs of the two Vector Mixers (in the Mini Case). I control one of the two VCA with the Espression (Volume) Pedal.

    The two Planar Vector Mixers (with joystick) are in the Mini Case in front of the Buchla. I get the 8 audio inputs into the Mini Case via a Doepfer "Multicore" set, so that the 8 channels are sent via an Ethernet cable (and the mini patch cables can be hardwired to the modules). The alternative would be a real cable chaos with 8 long cables criss-crossing the instrument. The mix-out of the Planar modules is fed back over another Ethernet cable - into the Dual VCA, which I use to control the volumes of the mix-outs.


Original Buchla Case
  • 201e-18

    My Case is a 201-e 18U Case - the same as in the photo above. The "U" units denote the width of the modules. So it fit 3x6 = 18 modules in this case - but there are also double- and triple module sizes. With closed/folded case the three "6U Boats" are closely interlaced and the median Boat is behind the sides of the outer Boats. This makes the removal of the patchcables unavoidable.

    This folding-case concept is so consistently oriented to reduction with a low weight, that it made the "race" against a cabled transport.

    Because of the segregation of CV and Audio (Banana, Tini Jax) and a lower module number the effort of patching is not comparable with MOTM or Eurorack. It's noticeably faster. So you do not forget where cables are patched.

    Buchla Cases have small holes in the boats, which are intended for rear panel connectors. The Breakout Panels are installed from the inside, such as the Back-Panel of the 227e System Interface (see picture). XLR Mic In and 4x Jack (6.3mm) Out. Good thinking!

    The 201e-Case is incredibly light weighted! That too was a criterion for me, but it's not difficult to recognize that the instrument is not well protected. There are special Hardcases, though a lot of air make them much larger than the folded instrument.

    201e-18 Case on Buchla.com

    That's why I got a cover from Hot Covers (UK) for transport: a tailor-made "sweater" that protects the instrument and is super-light and practical. The cover also has a bottom with Velcro closure, which is easily opened and closed. With £ 48.-, this cover was also much cheaper than a hard case! It is enough to send the measurements (of the case) to Hot Covers by mail.

    Hotcovers Website

    Expansion Boat

    The 4U Top-Boat on my Buchla 201e-18 case is a Buchla-6U boat from a third-party manufacturer. The wooden side panels I made myself. On the rear I have built-in a 4-pin XLR socket for the current. I also installed such a socket into the 201-18 case and therefore can connect the boats with a 4-pin XLR cable. Next is a banana socket with ground (black) and the On/Off Switch (Row Power) for the Eurorack modules.

    The grounding of the Eurorack I have laid out externally - in order to be able to easily separate the systems (Buchla + Eurorack) for testing, in case of a humming problem. The ground cable runs to the grounding output of the 201e case.

    Because the 201-e 18U Case is too small to carry all my modules I built the removable top boat that includes a U-profile for the Expert Sleepers Eurorack modules (across the width / 65cm). The top boat is attached to the Buchla Case with 2 drawbolts on the side panels. They keep both floors bomb-proof and the mount and removal couldn't be easier.

BUCHLA peculiarities

in the CV control by other formats
  • Unipolar vs. Bipolar

    The big difference to other modular formats is the uni-polarity. This means that Buchla only wants positive values (0-10V), whereas Bi-polar systems are ±5V. Both are therefore 10V pp and theoretically a 5V offset shift would suffice. In practice, however, it is a bit different.

    If an external system is connected, it is first necessary to connect the grounding of both systems. On Buchla instruments is therefore a Banana-socket (on the rear). How a suitable cable is set up in the other system is shown on the left, using the example "Eurorack" (16 and 10 pin ribbon cables are the typical connections in Eurorack). This is also the most important step for a good connection.

    Grounding problems would show up through hum. For a quick analysis of such disturbances, I recommend not to make this connection internally, but externally - with a Banana Patchcable. With the external connection, the systems can be electrically isolated from each other for easy testing.

    For connections from the Expert Sleepers modules I made my own adapter cables. Since only the TIP connection must be connected, this was very simple and very cheap. From one banana cable iI created two adapter cables. At the same time, I have introduced the color code "green" for CV cables from Computer.

    0-10V - Unipolar

    CV control brings the ±5V comes into play with the Eurorack Expert-Sleepers Expanders: Buchla wants 0-10V and the ESX-8CV module delivers ±5V in the delivery state. The first thing I noticed was the jumper - it changes the current in ± 9.13V. Taking only the positive values would be 0-9.13V. This would be sufficient for most applications, but two problems remain: The "last volt" is missing, or 0.87V, and, by elimination of the negative values, only 11 bit (0-2047) remain. The resolution is still high enough - nevertheless, I would have rather 12 bit - and this is much easier than originally thought.

    The picture (right) shows that in my instrument are actually only 16 inputs, which absolutely need 0-10V (because they are not connected with the sliders). My compromise is (because I have never used all 16 inputs at the same time), that I use one of five Expanders (8x CV) on the 9.13V / 11bit control. Since (in this case) 10V stand for + 6dB, it isn't painful that I can't generate the 10V. Should I use these CV channels on other modules, I only need to adjust the offset (and may have to remind the 11bit resolution). A very comfortablse situation.

    Since most CV inputs on the Buchla are connected to a potentiometer, the offset can be adjusted with the potentiometer. In most cases this is even better than 0-10V, for e.g. the "LoPass Gate 292", the potentiometers should be in the 0 position to be controlled by CV. By the +5V shift, the 0 position changes to 12 o'clock and this has the effect that the envelope curves can be reduced when the potentiometer is controlled to values below 12 o'clock. I am very much in favor of this.

    A view with the settings of my Expert Sleepers Expanders. It is one ESX-8GT MkI Gate Expander and four ESX-8CV CV Expanders.


    On the ESX-8GT MkI one of the level jumpers is set, so 4 outputs have 11.54V output (instead of 5V) - but this is only possible with the MkI modules as they are powered (ESX-8GT MkII modules are passive).


    Only one ESX-8CV expander is not in the delivery state: the jumper is set to ±9.13V and with the trimmer the output was maximized to 9.54V.

    Buchla Pulses

    Buchla produces very different Pulses. On the Sketch from Chris Muir it becomes clear. One problem is, that the Gates/Trigger/Pulses should not be longer than 4ms. The Pulse of the "Function Generator 281" is even only 0.5 ms short. The second problem is that the typical Buchla "Stepped Pulse" consists of a >8.5V Trigger and a 5V Gate.

    To make it short: the best solution is the Synovatron GT Elements. To the right, the incoming gate is to be seen, and the Buchla Pulses generated therefrom. Audible better!

    Synovatron Website


    Synovatron has a solution too, but I do not need it, since I work with Max. Only the 4ms at the trigger length are problematic and a swallow of single signals is likely, which can only be controlled by the "Audio Interrupt Mode" (in Max). I don't want that because the name is also program.

    Read more on my hybrid synth page.

    My hybrid Synth