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A-Series 1 Modular Synth

Modular Components

Ochen K.

Video clips

The A-Series Modular Synth is the first fully modular synth for Reason, where you can design your synths however you want for whatever sound you can imagine. And because all the modules are mix-and-match, all those Reason effects and devices that you already have can go right inside your custom synth. The A-Series 1 is the first rack extension in series.

Product details

(Current version 1.0.4 - see update notes below for details.)

The A-Series Modular Synth is a set of modular synth components to allow you to design your own synth in Reason. The A-Series components aren't hard-coded together, meaning that the audio and CV signal paths between all the components that make up your synth are completely up to you.

The A-Series 1 is the firsts of two rack extensions to launch in the A-Series. The other is the A-Series 2. The A-Series 1 contains a midi-to-CV converter, a VCO, an envelope generator, a VCA, and an LFO. The A-Series 2 contains a poly splitter, a sample and hold, a noise generator, a VCF, a ring modular, and a mixer.


The A-Series 1 rack extension contains the following modules:

A-19SEQ - A midi-to-CV converter, receiving midi signals from a midi keyboard or the Reason sequencer, of from rack sequencers like the Matrix, and converts the signals into CV (note) data and gate (velocity) data. These signals can then be routed to control any other device, such as a VCO or envelope generator.

A-11VCO - A voltage controlled oscillator generating four waveforms - saw, square, triangle, and sine - all at the same time. The A-11VCO has a 7-octave range with coarse and fine tuning, can accept and mix a second pitch modulation signal to create FM-like effects, and can modulate the pulse width of square waves. Each parameter can be controlled by CV input.

A-14ADSR - An envelope generator with three speed ranges and standard attack, decay, sustain, and release parameters. Each parameter can be controlled by CV input.

A-13VCA - A voltage controlled amplifier allowing multiple signals to control a sound’s gate shape, with two gain CV ins and a two-in audio mixer. Each parameter can be controlled by CV input.

A-14LFO - An LFO with four signal waveforms - saw, square, triangle, and sine, three cycle speed ranges, with both free-running and tempo-synced cycles, and pulse width modulation of the square wave signal. Each parameter can be controlled by CV input.


Here are some videos to help you learn more about the A-Series and how to use each component.

More information about the A-Series in general:

An introduction to the concept of modular synthesis:

The A-19SEQ midi-to-CV converter in detail:

The A-11VCO voltage controlled oscillator in detail:

The A-14ADSR envelope generator in detail:

The A-13VCA voltage controlled amplifier in detail:

The A-14LFO in detail:

If you have any questions or suggestions, send them to [email protected]

** 1.0.2 UPDATE **

1) Bug fixes relating to note cv out resetting on gate-off messages. 2) Other minor fixes.

** 1.0.4 UPDATE **

Reason 7.1 compatibility update



Released: 2014-03-07
Version: 1.0.4