Analogue Systems RS-35 External Processor


The RS-35 External Processor contains three circuits for extracting coltrol voltages from an audio signal: A frequency-to-voltage generator, a level-to-voltage generator and a trigger generator.



Frequency-to-voltage (FREQ-V): This circuit of the RS-35 circuitry is also known as "pitch-to-voltage converter". It analyzes an audio signal and creates a frequency dependent control voltage. The higher the frequency the higher the voltage is.
The input accepts signals of ±10V. The V-Slew control can smoothen abrupt changes in the output signal and thus create a portamento up to 2 seconds long.

The "V-range" switch determines the voltage range at the output:
In the 1V/oct mode it will generate a control voltage with 1V/octave characteristic and a range of -4V to +3V.
In VARY mode the "vary depth" control sets the onversion range from 0V to 0.5V/oct. In this mode the voltage range at the output is -10V to +6V.

The switch "F-Range"sets frequency range to be analyzed. "kHz" converts frequencies from 20Hz to 1.2kHz with a accuracy better than 1%. "10kHz" converts frequencies from "100Hz to 10kHz with an accuracy better than 2%

HELD-V: Without an input signal the voltage will not drop back to zero but insead it will be held until the next trigger is generated by the according section (see below). Accuracy is 5% in low bass (20Hz to 100 Hz) and 1% in 100Hz - 1.2Hz range. In the 10kHz mode of the FREQ-V circuit the accuracy is constantly 2% over the whole 10lHz range.

Level to voltage (LEVEL-V): This unit is commonly known as "envelope follower". It produces a control voltage depending on the amplitude of the audio signal. A LED shows activity. Abrupt steps in the signal can be smoothened with the LV-SLEW contol (max. 1s). LV-LEVEL controls output level from 0V to +10V.

TRIGGER: A +5V pulse wave is generated from the audio signal in the range betwenn 1Hz and 10kHz. The circuit´s sensitivity is adjusted with  the TRIG-SENSE control.


Usage with Eurorack:
Analogue Systems' modules are designed solely for use in cases and cabinets made by Analogue Systems. Through the use of adaptors or adaptor cables, however, it is possible to connect them to Eurorack cases.
Should you chose to use an Analogue Systems module in an Eurorack case, please note that the warranties are thus void and the use occurs at your own risk! If the module is plugged in incorrectly and therefore damaged the customer has to bear any costs for repair and shipping!

Because of the different position of the mounting holes there will be a gap of 0.5HP (= 2.5 mm) when mounting an Analogue Systems module next to a Eurorack module. Take this into consideration when planning your system. Gaps can be covered with 1.5HP wide blank panels by Doepfer.


Signal input: Freq-In
CV outputs: Freq-V-Out, Held-Out and Level-Out
Trigger output


3U module in Analogue Systems form factor, 12HP wide, 61mm deep
power consumption: 25mA

0.199 kg
Article Number
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€ 19% VAT excl. €197.48 € 19% VAT incl. €235.00
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