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System A - 100

RCV

A-149 /1

1. Introduction

Module A-149-1 is a Random Control Voltage

Source based on the idea of Don Buchla's "Source of

Uncertainty 265/266" modules. It has available 4 ana-

log random voltages, that are generated in different

ways.

The Quantized Random Voltages section has avai-

lable the outputs N+1 and 2

States. N is an integer

number in the range 1...6 that can be adjusted manu-

ally (Man N) and by an external control voltage CVN.

The voltage steps are 1/12 V for the 2

output (i.e.

semitone intervals) and 1.0 V for the N+1 output (i.e.

octave intervals).

The

Stored Random Voltages

section has available

an output with

even voltage distribution with 256

possible output states and another output with

ad-

justable voltage distribution probability. The distri-

bution of this output can be adjusted manually (Man D)

and by an external control voltage CVD. The voltage

range is 0...+5 V for both stored random outputs.

The rising edge of the corresponding Clock input

signal triggers a new random voltage value at the

outputs.

Each output is equipped with a LED that displays the

current output voltage.

CV N In Man N

A-149

Clk In

RCV

n+1

CV N

Quantized RV

CV D In Man D

Clk In

CV D

Stored RV

Remark: The A-149-1 can be expanded by the A-149-2

module (8 digital random outputs with LED displays)

Summary of content (6 pages)

PAGE 1
System A - 100 doepfer RCV A-149 /1 1. Introduction A-149 RCV CV N Quantized RV CV N In Man N n+1 Clk In 2n CV D Stored RV CV D In Man D Clk In Remark: The A-149-1 can be expanded by the A-149-2 module (8 digital random outputs with LED displays) Module A-149-1 is a Random Control Voltage Source based on the idea of Don Buchla's "Source of Uncertainty 265/266" modules. It has available 4 analog random voltages, that are generated in different ways.
PAGE 2
A-149 /1 RCV System A - 100 Controls and Indicators: 2. Overview ➁ ➊ ➀ ➋ ➅ ➎ ➄ ➏ 2 doepfer 1 Man N : manual control of “N” 2 CV N : attenuator for CVN at input ! 3, 4 LED : display for output § resp. $ ➂ ➌ ➃ ➍ 5 Man D : manual control of distribution "D" 6 CV D : attenuator for CVD at input & 7, 8 LED : display for output / resp.
PAGE 3
RCV A-149 /1 System A - 100 doepfer 3. Controls 2 CVN 3.1 Quantized Random Voltages The external control voltage CVN fed into input ! is attenuated with this control. 1 Man N 3 LED This is the manual control for the integer number N in the range 1 to 6. It defines the number of possible states at the outputs § and $: The brightness of each LED is proportional to the output voltage at the corresponding output § resp. $. • 4 LED 3.
PAGE 4
Häufigkeit probability A-149 /1 RCV D~0 System A - 100 D=5 D ~ 10 doepfer 4. In- / Outputs 4.1 Quantized Random Voltages ! CV N In This socket is the Control Voltage input for the parameter "N". " Clk In Zufallsspannung [V] output voltage Fig.1: Probability distribution for different settings of "D" H The final value of D is the sum of the manual control 5 and the external (attenuated) control voltage applied to input %.
PAGE 5
doepfer System A - 100 RCV A-149 /1 4.2 Stored Random Voltages 5. User examples % CV D In The Doepfer web site www.doepfer.com shows some typical examples of the A-149-1, including sound examples in the mp3 format. Even more details concerning the technical realization of the module can be found. An excellent description of several applications of random voltages like those generated by the A-1491 can be found in the Allen Stranges "Electronic music - systems, techniques and controls" from page 82.
PAGE 6
A-149 /1 RCV System A - 100 tempo of the VCLFO A-147. Thus as the range of pitch selection increases the number of possible spectral ranges becomes exponentially (or geometrically) greater. As the tempo of the VCLFO is controlled by the 2n output too, bright sounds are accompanied by longer events, longer events are accompanied by greater range pitch range possibilities and the number of of range probablities for pitch selection is correlated exponentially.