MODULES

The SW901 Voltage-Controlled Oscillator is a widerange generator of repetitive waveforms, the frequency of which is controlled by the sum of applied control voltages. The total frequency span of the oscillator is 0,1 to 15.000 Hz in six overlapping ranges. Four waveform outputs are available: sawtooth, triangular, sine and pulse. The width of the pulse waveform is continuously variable, by means of a front panel potentiometer, from complete symmetry to 8.1 asymmetry. One fixed and one variable output are available for each waveform.

This Module is based on the original design from 1964

The SW901A Oscillator Controller and the SW901B Oscillator are, respectively, the controlling and the oscillating / wave-shaping sections of the SW901 Voltage Controlled Oscillator. The separation of the functions of the SW901 into two modular instruments allow the assembly of a bank of oscillators, all of which are controllable from one controller. The SW901A panel contains the control voltage input jacks and potentiometer which vary the frequencies of all the controlled oscillators simultaneously. The SW901B panel contains frequency range controls and fixed level output jacks for each waveform. One controller may control up to 7 Oscillators. A bank of oscillators in which the intervals between the frequencies remain constant as the frequencies themselves are varied obviously has great musical value.

This Module is based on the original design from 1964

The SW921 Voltage Controlled Oscillator is a variable waveform generator which produces frequencies ranging from 0,01 to 40.000 Hz. Four waveforms are available: sine, triangular, sawtooth and rectangular with variable duty cycle. Both fixed and variable levels can be obtained from front panel output jacks.Voltage controlled
rectangular width is set by a knob and with accompanying voltage input jacks. Clamping point (waveform reset control) may be set by a knob and accompanying trigger inputs. Multiple frequency control inputs can be plugged into this module in parallel. This module functions as both an audio or control voltage generator.

The SW921A Oscillator Driver is a control voltage processor which runs associated SW921B oscillators through internally wired connections. The SW921B generates frequencies from 1Hz to 40kHz minimum. This oscillator generates both sub-audio and audio frequencies for control and audio signal use. Fixed level outputs for sine, triangle, sawtooth and rectangular waveforms are available. DC Modulate is a linear frequency control input, AC Modulate input is a capacitor coupled circuit. SW921B Oscillators may be phase locked together via the Synch Input Jack and the associated three position Synch Switch. A sawtooth waveform is recommended for best synchronization results. This Module is based on the original design from 1974.

SW904A Voltage-Controlled Low Pass Filter attenuates frequencies above the fixed control voltage cutoff point at a rate of 24 dB per octave. The cutoff frequency is voltage controlled through the control input jacks. The sum of the applied control voltages doubles the frequency of the cutoff point for each one Volt increase. The regeneration potentiometer varies the amount of internal feedback, creating a resonant peak at the cutoff frequency. This resonant peak will break into oscillation at clockwise settings of the regeneration potentiometer, creating a voltage controlled sine wave generator. The fixed control voltage potentiometer covers a 12 Volt (octave) range. The overall range of the FCV potentiometer is determined by the Frequency Range switch, which moves the frequency cutoff range in twooctave steps.

This Module is based on the original design from 1970

The SW904B Voltage Controlled High Pass Filter attenuates input signal frequencies below its nominal cutoff setting. The attenuation below FCV cutoff setting is 24 db/oct. As the fundament is generally the loudest frequency component of a complex tone, deletion of the lowest frequency range can radically alter the timbre. The FCV cutoff point is raised or lowered in octave per volt control inputs. The Frequency Range switch sets the overall range of frequencies covered by the Fixed Control Voltage potentiometer. The Low range encompasses 4 Hz to 20 kHz, while the High range shifts 1,5 octaves up to 10 Hz through 50 kHz.

This Module is based on the original design from 1966

SW904C Filter Couples is a connecting module which combines the functions of the 904A Lowpass and 904B Highpass Filters together. In the “off” position, the Highpass and Lowpass Filters are disconnected from the 904C and may be used independently. When switched to the “Brandpass” mode, Highpass and Lowpass Filters are coupled in parallel to process a central band of frequencies – deleting both bottom and top. The bandreject mode presents the inverse relationship, rejecting a central frequency band, and passing only the lowest and highest frequency components. Voltage controlled bandwidth and center frequency controls are included on the coupler. Bandwidth can be etended to three octaves with manual settings or control voltage. Center Frequency ranges from 5Hz to 20kHz, via manual or voltage controlled settings.

When using the 904C for Bandpass or Bandreject filtering, the following standard settings should be obeserved:

Note: 
Passband settings = Bandwidth knob plus control voltage.
Notchwidth = Minus bandwidth knob minus control voltage.

The SW907 and SW907A Fixed Filter Bank are non-voltage controlled modifers, who emphasize or reduce the gain of the center frequency bands indicated on each of the eight center potentiometers, in addition to the cutoff points set by low pass and high pass lters at either frequency extreme. A total of 10 overlapping LC networks are included.

The SW907A Fixed Filter Bank is a non-voltage controlled modifier, which emphasizes or reduces the gain of the center frequency bands indicated on each of the eight center potentiometers, in addition to the cutoff points set by low pass and high pass filters at either frequency extreme. A total of 10 overlapping LC networks are included.

This Module is based on the original design from 1968

Similar in function to the Moog 907 Fixed Filter Bank, the SW914 Extended Range Fixed Filter Bank is a non-voltage controlled modifier with 14 separate passband controls: high-pass, low-pass, and 12 center frequency knobs. Each passband range has an attenuation slope of 12 dB per octave above or below the center frequency indicated.

The White and Pink noise outputs of the 923 Random Noise/Filter module produces continuous bursts of random frequencies and wave shape throughout the audio spectrum. The two manual sweep filters, Lowpass and Highpass, are single pole circuits with a frequency cutoff slope of 6dB/octave.

The SW902 Voltage-Controlled Amplifier is a differential input and output circuit which gives an overall voltage gain of 2 (6 dB) when manual control potentiometer is at maximum, or when a control voltage of 6 Volts is applied to the control input. Two modes of gain are available: Linear and exponential.

This Module is based on the original design from 1969

The SWCP3 module is a 4 x 1 mixer with positive and negative outputs and a maximum gain of 2. This mixer can combine both AC and/or DC voltages.

This Module is based on the original design from 1968

The SWCP3H half size module has has the same function like the SWCP3 plus a multiple in addition.

The SWCP3H-Switch has the same functionality like SW CP3 but in addition it containes routing switches for 4 external CV´s to the above Oscillator Bank like on the SW 3P-2020.

The SW984 Four Channel Matrix Mixer is an AC coupled 4-input, 4-output matrix with bass and treble tone controls for each output channel. Each input has a separate attenuator for each of the four output channels. Thus, a matrix of 16 input attenuators provides maximum channel separation, or variable combinations of volume balance. Tone controls for each of the output channels can attenuate or emphasize bass or treble signals. Flat signal response is achieved with the control settings kept at “5” on the potentiometers. These are 2-pole active tone controls.

At the introduction of a V-trigger signal from an external source, the SW911 Envelope Generator produces a single voltage contour whose time/voltage variation is determined by potentiometers T1, T2, T3, and a time constant sustaining level potentiometer (Esus). The release of the V-Trigger signal will direct the voltage contour to T3 (final decay) regardless of what stage (T1, T2 or E) was in current operation.

This Module is based on the original design from 1968

The SW911A Dual Trigger Delay is designed to be used with 2 or more SW911 Envelope Generators. It provides one or two time delays on an input trigger voltage – bound for the activation of an envelope V-trigger. Delay stops immediately upon termination of input trigger.

Three different modes of operation are available via coupling mode switch:

OFF: Delays are activated independently through individual trigger inputs

PARALLEL: Trigger input on top SW 911A activates timing circuit on both simultaneously.

SERIES: Trigger input on top 911A activates top timing circuit, then triggers second timing circuit upon delay time of first.
 

This Module is based on the original design from 1968

The SW912 Envelope Follower produces two functions, which can be used separately or in conjunction. The follower circuit signal input presents a control voltage output (DC) proportional to the average amplitude of the AC input signal. The second function, a Schmitt trigger, generates a V-trigger above a threshold voltage (comparator), when a slowly varying or DC voltage is introduced at the control input jack. The normalling of the control output of the follower circuit to the control input of the Schmitt trigger circuit allows both control voltage and trigger to be generated from a single variable source.

The Random Signal Generator produces continuous bursts of random frequencies and waveshape from approximately 25 Hz to 20 kHz. Two types of energy distribution are provided: White noise and pink noise. The former distributes amplitude evenly throughout the indicated audio spectrum. The latter reduces the amplitude of each frequency increment proportionally to produce equal energy per octave. Pink noise, thus, sounds “lower” in pitch to the ear.

This Module is based on the original design from 1969

FUNCTION DESCRIPTION SW REVERSIBLE ATTENUATOR

The Reversible Attenuator processes a control voltage destined for the CV input of a speci c module. As the knob rotates counter-clockwise from 10 to 0, the proportion of the control voltage applied to the input jack that appears at the output jack decreases from 100% to 0%. As the knob rotates past 0 toward -10, the output voltage will rise to 100% of the input voltage but the polarity will be reversed.
 

FUNCTION DESCRIPTION SW995

The SW995 Attenuators panel consists of three „passive circuits“, each made of a 25k potentiometer between input and output. The signal input to the top attenuator is chained to the bottom two in series. Introduction of a patch cord into middle or bottom input breaks the normalling system. Attenuators reduce the gain or amplitude of any applied input signal, con- trol or audio.
 

FUNCTION DESCRIPTION SW994

The dual multiple panel consists of two sets of four jacks. Each set of jacks has been wired together. The multiple is a “device” which permits multiple distribution of one signal to several different places. This process is often called signal splitting. Multiples are used for many purposes; from linking two patch cords together, sending a single signal to several differ- ent modules at the same time.

The multiple part consists of three sets of four jacks. Each set of jacks has been wired together. The multiple is a “device” which permits multiple distribution of one signal to several different places. This process is often called signal splitting. Multiples are used for many purposes; from linking two patch cords together, sending a single signal to several different modules at the same time.

The Attenuator part consists of three „passive circuits“, each made of a 25k potentiometer between input and output. The signal input to the left hand attenuator is chained to the right hand two in series. Introduction of a patch cord into middle or right hand input breaks the normalling system.

Attenuators reduce the gain or amplitude of any applied input signal, control or audio. Moving clockwise from zero gain to unity gain with input, these attenuators can be used for reducing the effect of a control upon a voltage controlled module, providing up to three variable outputs from a single source input or reducing the gain of an entire signal complex.

The SW905 Reverberation Unit utilizes a dual springtype acoustic delay line to produce a succession of decaying echoes of an audio signal. A single panel control determines the ratio between the amounts of reverberated and non-reverberated signals that appear at the output jack. In addition the SW905 offers two modes of operation:

Regular mode
the relative amount of the echo signal and direct signal can be continuously changed from 100% direct signal to 100% echo signal.

„Emerson“ modification
the output signal is continuously mixed with the direct signal and the knob on the faceplate controls the level of the mix. The direct signal is passed through unaffected.

Both modes of operation can be selected on the board of the module.
 

The SW 960 Sequential Controller has a wide variation of functions, both as an independent module and in combination with the SW 961 Interface and SW 962 Sequential Switch. The sequence module consists of a voltage controlled clock oscillator which drives three rows of eight steps each. Voltage range switches for each row determine the DC voltage range of each pot. Jacks for trigger inputs and outputs appear below each column. Timing control for the eight steps is accomplished via the Third Row Control of Timing switch.

Four independent circuits are found on the SW 961 Interface: One Audio-In to V-trigger Out circuit, one S-trigger In to V-trigger Out circuit and two V-trigger In to S-Trigger/V-trigger Out circuits. All interface circuits may be used simultaneously, in combination or separately.

The SW 962 Sequential Switch selects between two or three signal inputs, coupling one signal to the output at a time. A V-trigger pulse introduced to the Shift Input initiates the sequence.The sequential switch will alternate between stages one and two until a standard phone plug is patched into Signal Input Three.