The Buchla One Hundred Series

 

 

Welcome to the online resource for the Buchla 100 modular music system. Designed by Donald Buchla in the 60’s for the San Fransisco Tape Music Center to replace their ageing equipment which were described as ”…ingenious application of surplus equipment that saw service in World War II bombers…”. The basic objectives were to build something portable, flexible, cheap, and transistorised. The 100 system was later sold to the, now defunct, music division of CBS. This is however not a history not a history lesson regarding the Donald Buchla legacy — This site is a  catalog of the modules made in the 100-series. If your aim is to know more about the STMC and electronic music in the 60’s and  it’s better to find literature about the subject.

The One Hundreds is a resource and personal endeavour. As such it’s not a commercial project and nothing will be made available to the general public.

Technical Specifications

The 100 series are made out of modules which are 7″ high and 4.25″ (or any integral thereof) wide. The system employs three varieties of signals, each with a distinctly different function :

Audio signals, the raw material of electronic music, are formed by various sorts of generators (sine, square, sawtooth, harmonic) or are produced externally (tape loop,
radio, microphone). In constructing a piece, they may be filtered, gated, mixed, modulated, or otherwise processed. The patch cords carrying audio signals within the system are grey, shielded cables terminated with miniature phone plugs. A standard level of Odb (ref.600Ω) isemployed for audio signals within the system.

Control voltages, used to determine frequencies, envelope characteristics, amplitudes and other parameters, are generated by keyboards, programmable voltage sources, and format generators. Black banana plug patch cords are used to interconnect control voltages. The standard control voltage range is from .5 to 15 volts.

Timing pulses are originated by keyboards, programmable sequencers, and pulse generators. They are used to trigger notes, open gates, or initiate chains of musical events. Timing pulses are about 10 volts in amplitude and are interconnected with red banana plug patch cords.

The rules for interconnection are straight-forward. Any number of inputs may be connected to a single output. Timing pulse outputs may be paralleled and con- nected to one input. The system output may be derived from any module; output is of sufficient magnitude to drive line inputs on tape recorders or sensitive inputs on power amplifiers.

Power is +15V for all modules with an additional +24V for some.

 

Modules

All known modules are presented with text from the 1968 catalog. Price from the same catalog with the price in brackets are adjusted for inflation (2018). Images of some modules are missing: 117 because it’s unknown what it looked like (The 157 was listed before, but I have received a picture of it since, so now I just have to build it). 150, 172 and 176 because of lack of schematics. 185 is built with 2 x 196, 1 x 110, and a 106 — All stock, except the 106, which is modified to get the inverting function for the down shift. What this modifications looks like is unknown. The 113 and 120 seems to be left out of the catalog, perhaps because only one set were built for David Tudor, a guesstimation would be that it’s two 114 and two 107 in a different outfit. The 132 is also missing, only one was ever built. If you have any information regarding any of the previously mentioned modules — please let me know. All modules represented here are copies of the originals, built from the original schematics.

 

 

 

MODEL 100 — CABINET

Specially designed walnut cabinet accommodates power supply and 15 panel units . (Most modules are 44″ x 7” and occupy one panel unit, but some are 82″ or 17″ wide and occupy two or four panel units .) Overall dimensions are 23″ x 23″ x 8″ .

Units — 15
Price — $70 ($499)
Supply — n/a

 

MODEL 102 — DUAL STEREO LOCATOR

Dual panning controls.

Units — 1
Price — n/a
Supply — +15V, 1mA / +24V, 4mA

 

MODEL 106 — MIXER

Two 3-channel mixers with both separate and common outputs and level controls for each input.

Units — 1
Price — $75 ($535)
Supply — +15V, 14mA

 

MODEL 107 — VOLTAGE CONTROLLED MIXER

Two 5-channel mixers with both separate and common outputs . Input levels are controlled by externally applied control voltages usually derived from a Model 114 touch controlled voltage source.

Units — 2
Price — $350 ($2,500)
Supply — +15V, 191mA

 

MODEL 110 — DUAL VOLTAGE CONTROLLED GATE

Two voltage controlled amplifiers generally used in conjunction with a Model 180 attack generator to control the envelope of applied signals.

Units — 1
Price — $100 ($710)
Supply — +15V, 37mA

 

MODEL 111 — DUAL RING MODUALTOR

Two independent ring modulators. Each output consists of the sums and differences between frequency components of two input signals. Original signals are suppressed about 55 db.

Units — 1
Price — $165 ($1,175)
Supply — +15V, 62mA

 

MODEL 112 — TOUCH CONTROLLED VOLTAGE SOURCE

Touch activated keys produce one of twelve preselected voltages at each of two outputs. A third output voltage is proportional to finger pressure, and a fourth output is a pulse generated whenever a key is activated. Generally used to initiate notes and control their pitches.

Units — 5 (16 step)
Price — $310 ($2,200)
Supply — +15V, 85mA

 

MODEL 114 — TOUCH CONTROLLED VOLTAGE SOURCE

Ten independent, touch activated keys, each with a corresponding control voltage output and pulse output. The voltage outputs are particularly useful for controlling gates (110 or mixers 107), and the pulse outputs for initiating attack waveforms 180) or other events.

Units — 4
Price — $310 ($2,200)
Supply — +15V, 89mA

 

MODEL 115 — POWER SUPPLY

Regulated supply for powering a cabinetful of modules plus one or two keyboards. Installed in Model 100 cabinet, unit occupies no panel space.

Units — n/a
Price — $100 ($710)
Supply — n/a

 

MODEL 117 — DUAL PROXIMITY DETECTOR

Two capacitance-actuated control voltage sources for enabling spatial control of sound parameters. Theremin-style antennas may be remotely located. (Note: Schematic marked with ”Ask Buchla about this circuit, what is it used for”).

Units — 1
Price — $250 ($1,780)
Supply — n/a

 

MODEL 123 — SEQUENTIAL VOLTAGE SOURCE

Produces a sequence of two to eight programmed voltages at each of three outputs. Switching is accomplished by applying a pulse, usually from a Model 140 pulse generator. Indicator lamps show which of the 24 potentiometers are in control. Eight pulse outputs are energized as corresponding segments are switched. Unit may be used to simultaneously program pitch, amplitude, and duration of single or repetitive sequences of notes.

Units — 2
Price — $280 ($1,995)
Supply — +15V, 37mA

 

MODEL 124 — PATCHBOARD

Consists of 24 miniature audio jacks mounted on a panel. Used in studio installations to facilitate connection to tape recorders, monitors, and other auxiliary equipment.

Units — 1
Price — $35 ($249)
Supply — n/a

 

MODEL 130 — DUAL ENVELOPE DETECTOR

Produces a control voltage proportional to the instantaneous amplitude of an applied signal. Detector time constant is variable from .01 to 1 second.

Units — 1
Price — $135 ($960)
Supply — n/a

 

MODEL 140 — TIMING PULSE GENERATOR

Produces repetitive pulses at intervals of .005 to 20 seconds. Period and duty cycle may be controlled internally or by applied control voltages.

Units — 1
Price — $150 ($1,070)
Supply — +15V, 38mA

 

MODEL 144 — DUAL SQUARE WAVE OSCILLATOR

Two independent oscillators in one unit . Frequencies are continuously variable from 5 cps to 20 kc and may be controlled internally or with externally applied voltages. There is provision for wide band amplitude and frequency modulation.

Units — 1
Price — $190 ($1,350)
Supply — +15V, 71mA

 

MODEL 146 — SEQUENTIAL VOLTAGE SOURCE

Produces a sequence of two to sixteen programmed voltages at each of three outputs. Otherwise identical to Model 123.

Units — 4
Price — $460 ($3,275)
Supply — +15V, 53mA

 

MODEL 148 — HARMONIC GENERATOR

Generates a fundamental and its first nine harmonics (harmonic numbers 1 – 10). Fundamental frequency is continuously variable
from 5 cps to 5 kc and may be controlled internally or with an externally applied voltage. There is provision for wideband frequency modulation. The 148 is frequently used in conjunction with mixers (106, 107), gates (110), and attack generators (180) to enable precise programmed envelope control of individual overtones .

Units — 2
Price — $950 ($6,790)
Supply — +15V, 7mA  / +24V, 106mA

 

MODEL 150 — FREQUENCY COUNTER

Four digit counter measures frequencies to 100 kc with a preci- sion of 10 cps. Frequencies below 10 kc are measured with a precision of 1 cps.

Units — 1
Price — $550 ($3,920)
Supply — n/a

 

MODEL 155 — DUAL INTEGRATOR

Produces continuous control voltage functions when used in conjunction with sources of discrete control voltages (e .g . key- boards, sequencers). Positive and negative slopes may be individually and continuously varied from 15 volts in .0025 seconds to 15 volts in 10 seconds; either or both slopes may be voltage controlled. Particularly useful for generating complex voltage controlled envelopes, frequency glides, and repetitive control functions.

Units — 1
Price — $225 ($1,600)
Supply — 15V, 23mA

 

MODEL 156 — DUAL CONTROL VOLTAGE PROCESSOR

Serves to mix, compress and invert control voltages. Each channel has two control voltage inputs and an internal voltage
source. Particularly useful for obtaining fine pitch control, transposition capability, and range compression of control voltage sources.

Units — 1
Price — $95 ($675)
Supply — 15V, 48mA

 

MODEL 157 — CONTROL VOLTAGE INVERTER

Four channel unit complements control voltages to accomplish a variety of inverted functions.
(Note: Schematic has been marked with ”Need inverters / Why can’t we make this circuit”)

Units — 1
Price — $95 ($675)
Supply — n/a

 

MODEL 158A — DUAL SINE • SAW GENERATOR

Two independent oscillators in one unit. Frequencies are continuously variable from 5 cps to 20 kc and may be controlled internally or with externally applied control voltages. Waveshape is continuously adjustable from sine to sawtooth; oscillators may be wideband frequency modulated.

Units — 1
Price — $200 ($1,425)
Supply — +15V, 70mA

 

MODEL 160 — WHITE NOISE GENERATOR

Produces white noise with a flat frequency distribution from 5 cps to 20 kc and weighted noise with a constant power per octave distribution.

Units — 1
Price — $75 ($535)
Supply — +15V, 23mA

 

MODEL 165 — DUAL RANDOM VOLTAGE SOURCE 

Produces two uncorrelated, random output voltages, each of which is changed by applying a trigger pulse . Used to randomize frequency, amplitude, and time.

Units — 1
Price — $175 ($1,250)
Supply — +15V, 104mA / +24V, 35mA

 

MODEL 170 — DUAL MICROPHONE PREAMPLIFER

Two high-gain mike preamplifiers. Input connectors are 3 pin XLR. Input impedences are selected by a panel mounted switch.

Units — 1
Price — $125 ($899)
Supply — +15V, 7mA

 

MODEL 171 — DUAL INSTRUMENT PREAMPLIFER

Two preamplifiers for electric guitars, contact microphones, and other low-level signal sources. Input impedences are 200 kΩ; input connectors are standard phone.

Units — 1
Price — $125 ($899)
Supply — +15V, 5mA

 

MODEL 172 — DUAL SIGNAL LEVELER

Two high-gain, constant-output amplifiers . Output signal levels are maintained at 0 db (± 1 db) for input variations of from -40 db to +10 db. Time constants are variable from .05 to 5 seconds.

Units — 1
Price — $190 ($1,350)
Supply — n/a

 

MODEL 175 — DUAL EQUALIZER – LINE DRIVER 

Used in studio installations to drive 600Ω headsets or unbalanced lines at a nominal +4 db (max. +20 db). Unit incorporates bass and treble controls of the variable turnover variety.

Units — 1
Price — $165 ($1,175)
Supply — n/a

 

MODEL 176 — DUAL HISS CUTTER

Reduces tape hiss by restricting bandwidth of signals that would otherwise be masked by high frequency noise. Signals above a certain threshold (including fast transients) are unaffected.

Units — 1
Price — $175 ($1,245)
Supply — n/a

 

MODEL 180 — DUAL ATTACK GENERATOR

Two independent units produce envelope control voltages initiated by pulses. Attack time is variable from .002 to 1 second; decay time from .002 to 5 seconds; duration from .002 to 5 seconds. Duration may be optionally controlled by trigger pulse length.

Units — 1
Price — $140 ($999)
Supply — +15V, 40mA

 

MODEL 185 — FREQUENCY SHIFTER

Shifts frequencies contained in input signal by an amount equal to the applied carrier frequency. Raised and lowered signals are simultaneously available.

Units — 1
Price — $420 ($2,999)
Supply — n/a

 

MODEL 190 — DUAL REVERBERATION UNIT

Two independent spring type reverberators. Degree of reverberation is continuously variable.

Units — 1
Price — $200 ($1,425)
Supply — +15V, 16mA / +24V, 100mA

 

MODEL 191 — SHARP CUTOFF FILTER

Voltage controlled highpass and lowpass filters with 24 db/octave slopes. Cutoff frequencies are variable from 5 cps to 20 kc with no range switching. Also functions as a bandpass filter with voltage controlled center frequency and bandwidth. (Note: Schematic has been marked with ”Discontinued / Very poor design”)

Units — 2
Price — $450 ($3,200)
Supply — +15V, 88mA

 

MODEL 192 — DUAL LOPASS FILTER

Two lowpass filters with cutoff frequencies variable from 200 cps to 20 kc. Slopes have sharp knees and are 12 db/octave.

Units — 1
Price — $140 ($999)
Supply — +15V, 74mA

 

MODEL 194 — BANDPASS FILTER

Divides an input signal into four frequency bands. Cross-over frequencies are 200 cps, 900 cps, and 4 kc. Slopes have sharp knees and are 12 db/octave .

Units — 1
Price — $135 ($960)
Supply — +15V, 30mA

 

MODEL 195 — OCTAVE FORMAT FILTER

Divides an input signal into ten frequency bands centered at octave intervals from 31 cps to 16 kc.

Units — 2
Price — $225 ($1,600)
Supply — n/a

 

MODEL 196 — PHASE SHIFTER

Shifts phase of input signal such that a 90° (±5°) phase relation- ship between the two outputs is maintained from 5 cps to 20 kc. Used in conjunction with ring modulators for frequency shifting or for exotic visual displays .

Units — 1
Price — $140 ($999)
Supply — n/a

 

 

 

My Own Modules

I’ve designed and built two modules to fit the 100-series. They’re both built using only resistors, capacitors, and transistors in the spirit of the older modules.

 

MODEL 154 — DUAL COMPARATOR

Two control voltage inputs are compared against each other. If respective input value is larger than the other, the corresponding pulse output jack will be high.

Units — 1
Price — n/a
Supply — n/a

 

MODEL 197 — DUAL HARMONIC ADDER

A discrete wave folder, input a sine and outcomes a single rich in overtones.

Units — 1
Price — n/a
Supply — +15V, 46mA

 

 

Thanks to Adam, Daniel, Mike, Mark and the other people who’ve helped out along the way.