NEW! AJH Synth DUAL RVG Random Voltage Event Generator

An Introduction to this Eurorack Generative CV Source video upload by AJH Synth Official

"This is the all-new, Limited Edition DUAL RVG module for Eurorack modular. It is based on the original EMS Random Voltage Generator, providing the functions of the original, but adding substantially more. It uses the same uni-junction transistor ramp & hold circuitry of the original, incredibly rare vintage unit. It produces 2 separate random voltages, that can be triggered by it's internal clock or external gate signals. However, unlike a a common Sample & Hold, it also has random variation of it's internal clock, the amount of which can be added/adjusted manually, or controlled by CV. Additionally, it has a gate output that can be used to trigger other modules in time with it's internal LFO, and also has Triangle and Sawtooth outputs, which are also affected by the internal LFO, although these can also be used as a voltage-controlled LFO, as the module's internal clock speed can also be controlled by CV.

This super-flexible Eurorack recreation is both authentic to the technology, character and behaviour of the original, whilst offering a serious amount of random goodness for experimental, generative music, whilst also having provision for more controlled duties, from regular twin Sample & Hold duties, to voltage controlled frequency modulation.

00:00 Intro
00:27 Overview
03:27 A Closer Look

10:49 Some usage examples"

Video by DreamsOfWires

The Dual Random Voltage Event Generator (Dual RVG) is a faithful replica of the vintage EMS Random Voltage Generator. It is an all analogue design which generates two separate random voltages that can be timed either from the internal LFO or from an external clock. However, one of the most interesting features is that varying amounts of randomisation can be added to the internal clock rate with the Time Vary control - so with this we can randomise time period in addition to voltage.

The TR-IN input allows an external clock to be used instead of the internal LFO. When the LFO is stopped two new random voltages can be generated with each press of the manual Trigger button.

We have added many useful features that were not present on the original design, including Level and Offset controls for both outputs, adjustable Slew on Output 1, control of internal LFO run / stop from an external Gate signal, control of LFO rate using an external CV, and the LFO output is brought out to the front panel as both a Sawtooth and Triangle wave and both of these waveforms are skewed as Time Vary is added to the LFO rate. We have also added a gate output that produces a gate for each internal clock pulse, and this gate length changes in proportion with the time variance. The duty cycle of the gate can also be varied from 1% to 99%.

Module Width: 14hp

Module Depth: 26mm (Including power lead)

Current Usage: 95mA Positive, 70mA Negative

Provisional Information
We have taken the original EMS RVG design and re-created it in Eurorack format, and added many extra features that make it a considerably more useful in a modern day modular system, but of course it can also be used with other synths too and with a suitable conversion cable it can be used with the original EMS VCS3 and Synthi A or Synthi AKS.

Limited Edition
The Dual RVG will be available with either a Black (Dark Edition) or Silver front panel. Just like the original EMS RVG the circuitry uses vintage unijunction transistors for both the ramp and hold and LFO circuits, these are quite rare and we have only obtained enough UJT's to build a limited number of modules, Therefore the Dual RVG module is being released as a once only, strictly Limited Edition of 250 units worldwide.

Expected delivery in first quarter 2022, and it can be pre-ordered from many AJHSynth retailers.

See the dealers on the right.