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.
The Model 285 is a development of Roman Fillipov and is not completely analogous - this can be seen on the 4th power cable, which leads 5V. I'm not really convinced of the sound and find that both, Shifting and Ring Modulation sound better with Max/MSP (more about Ringmodulation is here).
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.
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.