DOEPFER / A-118-2 Mini Noise / Random / S&H

Variations

A-118-2 Noise / Random / T&H / S&H is a slim size Noise, Random, Track & Hold, Sample & Hold module.

It has the same functions as the A-118-1 NOISE +RANDOM VOLT. in a size of only 4HP, allowing you to build a system that makes effective use of limited space. In addition, the A-118-2 has Track & Hold and Sample & Hold functions not found on the A-118-1.

The A-118-2 generates four types of noise: white noise, color noise, contunius random voltage, and step random voltage. The noise signal is generated 100% analog by amplifying transistor noise. Typically, white noise and color noise are used as audio sources, and random voltage is used as a control voltage.

The color noise can be mixed with red noise (low frequency component) and blue noise (high frequency component).

The continuous random voltage can control the rate of change (Rate) and amplitude (Level) of the random voltage. The contunius random voltage is generated by processing the color noise with an internal low-pass filter. Therefore, the color noise control settings (Red, Blue) also affect the operation of the random voltage. Dual color LEDs provide visual confirmation of the contunius random voltage (Red = positive output voltage, Blue = negative output voltage). (Red = positive output voltage, Yellow = negative output voltage)

The contunius random voltage is used as a source for T&H (track & hold) and S&H (sample & hold). The control type can be set to T&H or S&H.

T&H (Track & Hold)
As long as the input clock signal is “high”, the output signal of the module is the input signal (in the case of A-118-2, the contunius random voltage). As soon as the clock signal changes to “low,” the module continues to hold constant the contunius random voltage at the moment of change.

S&H (Sample & Hold)
As soon as the input clock signal rises, it continues to hold constant the input signal (contunius random voltage) at that instant.

A “digital signal (clock, gate, LFO square wave output, etc.)” is required such that the clock signal varies only between two voltages of 0 V or 5 V or higher. A slowly varying CV signal will not work.

Another dual-colored LED provides visual confirmation of the stepwise random voltage. (red = positive output voltage, yellow = negative output voltage)

IMPORTANT NOTE
After power-on, it takes several minutes for the two noise signals and the random signal to be generated. If the signal is not output immediately after power-on, it is not a malfunction.

The T&H / S&H function is realized by a pure analog circuit (electronic switch followed by a capacitor and buffer). The resulting capacitor is discharged by a resistor, so the output voltage is held and slightly shifted. The amount of shift depends on the environment, such as humidity and temperature.

Width 4HP
Depth 40mm
Current consumption
+12V : 20mA
-12V : 20mA