A pure analog, dual oscillator module for Eurorack. Great synthesizer sound starts with a great oscillator, and an oscillator is at the heart of every synthesizer voice.



We designed the Miasma Voltage Controlled Oscillator (VCO) to bring that classic '80s synthesizer sound back to Eurorack modular systems. We just couldn't find any currently available oscillators with the sound textures and capabilities that we wanted, so we had to design our own; and now you get to own one as well.



There are many unique capabilities built into Miasma that you won't find in any other oscillator module, like the built-in patching and cross modulation structures that make Miasma so flexible in your rack. However, it's all about the sound - so let's start with some Miasma audio samples, before we go into the technical details of how we make that sound possible (best listening with Headphones!) :

"Deep Bass Texture"

"Acid Squarewave Texture"

Miasma Front Panel

Miasma Features :

16 HP Eurorack Module (3U Standard Rack Height)

(2) Pure Analog, Triangle Core Oscillators (V3340D or CEM3340)

(8) Knobs, Course & Fine Frequency, PWM, & FM (A & B)

(2) Triangle Wave Outputs (A & B Oscillators)

(2) Sawtooth Wave Outputs (A & B Oscillators)

(2) Square Wave Outputs (A & B Oscillators)

(2) Sub-Octave Outputs (A Oscillator, 1 & 2 Octaves below)

(2) Volt per Octave Inputs (A & B Oscillators)

(2) Frequency Modulation (FM) Inputs (A & B Oscillators)

(2) Pulse Width Modulation (PWM) Inputs (A & B Oscillators)

(2) "Soft" Synchronization (Sync) Inputs (A & B Oscillators)

(2) "Hard" Synchronization (Lock) Inputs (A & B Oscillators)

(3) Audio Mixers, mixing the main three A & B Oscillator Outputs

Supports Bus CV & Gate Signals (with 16 pin power connector)

Requires only +12V/-12V (compatible with 10 pin power connector)

Miasma Outputs:

Each oscillator has three main outputs, namely, Square(Pulse), Triangle(Tri), and Sawtooth(Ramp) wave outputs. These are each +/-5 Volt bipolar outputs.

Miasma Main Outputs



Sub-Octave Outputs:

Miasma has an internal sub-octave generator on the A oscillator that gives you one and two octaves below the current Oscillator-A frequency. This gives you the ability to easily create Shepard Tones using three(3) octaves and only one stable, oscillator. The sub-octave outputs are also very useful for locking filters or other modules to a sub-harmonic frequency. The Sub-Octave outputs are 0.0 to +5.0 (Gate compatible) levels.

Miasma Sub-Octave Outputs

Cross-Modulation:

Miasma makes use of internal routing to allow the two (2) Oscillators to control and cross-modulate each other. Default internal routing allows Oscillator B to frequency modulate Oscillator A, just use the FM(A) knob to adjust the amount of modulation. Turn the FM(A) control to it's minimum to turn off that effect. Want to use a different modulation source? Just plugging a cable into the FM(A) input will break the internal/default routing that allows Oscillator B to frequency modulate Oscillator A.

Miasma Cross Modulation

Internal Mixers:

Each output from the A oscillator (each of Triangle, Ramp, Square wave)

is mixed with the corresponding B oscillator output, and routed to the B oscillator output jack. So, it's easy to create fat, doubled voice type output patches with no additional wiring or mixer modules needed. Or tune the oscillators to different intervals to play two octaves, or thirds, fifths, etc. The Volt/Oct A input also is routed to the Volt/Oct B input,

so that both oscillators track together, and are synchronized by default.

Miasma Audio Mixers

However, if you want to separate the outputs and route them differently, just plug into the corresponding A output (Ramp, Triangle, or Square) and that default mixing patch will be de-normalized(i.e. severed), putting the A output only on the A jack and the B output only on the B jack. It is this clever use of signal "normalization", that gives the Miasma such great sound with much less user patching effort. (it just works!)

Soft or Hard Synchronization:

The CEM3340 has very unique synchronization capabilities, including both soft (normal) and hard (reversing) sync, neither of which work exactly the same as other oscillators, due to the CEM3340 chip design. The figure below is from the original CEM3340 datasheet, and shows patterns when synchronizing the B oscillator to the A Oscillator output. Frankly, the weirdness with respect to sync is one of the things that make the CEM3340 chip so interesting, and why it sounds the way it does.

CEM3340 Hard Sync Patterns

By default, the Miasma VCO does a "soft" synchronization of the B Oscillator from the A Oscillator, without requiring a patch cable. However, if you don't want that configuration, just insert a plug or cable into the "Sync B" input jack, and that default or normalized patch will be broken, and each oscillator will be "free-running".

De-Normalizer:

We know, it sounds like something from "Men-in-Black", but really it's just a "dummy" 3.5mm Plug with a bicolor (Red/Blue) LED that shows the signal output on the jack it is plugged into (or nothing if you plug it into an input).

De-Normalizer



Our 3.5mm jack type includes what is called a "normal" connection, a connection that is made only when no plug or cable is inserted into that jack. We use the "De-Normalizer" to break those "normally made" connections. For example, if you wanted to break the default "soft sync" of the B oscillator from the A oscillator, just a plug a "De-Normalizer" into

the "Sync B" input jack, and now both oscillators are free-running.

CEM3340:

We chose to use the Curtis CEM3340 Voltage Controlled Oscillator (VCO) Chip for the core of the Miasma. The CEM3340 was the main oscillator chip used in quite a few classic synths, including the Oberheim OB-Xa, OB-Sx & OB-8, the Voyetra 8, Roland SH-101, MC-202, Jupiter-6, and early model MKS-80, the Sequential Circuits Prophet-5 Rev 3, Prophet-10, Prophet-600, Pro-One, Prophet T8, Moog Memorymoog, Banana Polysynth, Crumar Spirit, Digisound 80 VCO modules, the Synton Syrinx, and many, many more classic instruments.

Unfortunately, the CEM3340 chip was unavailable for many years, after the Curtis Electronic Music company stopped manufacturing them. Indeed the semiconductor process required to make those old devices was obsolete, and generally no longer available. However in 2016, the production of this great chip was restarted using an older/compatible semiconductor fabrication process, and now the CEM3340 is available in production once again. We have compared the sound of the CEM3340 Revision "G" with the Cool Audio V3340D and found no discernible differences between them.

Status:

We have already successfully completed several prototypes of the Miasma VCO, and have encountered no problems with the VCO design. The last remaining design task is the Aluminum front panel, as we have been using laser cut acrylic front panels for the preproduction testing versions. There are several good panel manufacturers, and we're working with them on getting quotations.

Production Schedule:

We've already produced half a dozen Miasma units for our own internal use, and we need your help to move Miasma to production. We're initially planning on a small production run of twenty-five (25) units for the limited "Early Bird" reward tier, and those should be available by early April 2018.

The next, larger production run will depend on the number of orders we receive for the main reward tier, but we are expecting to complete those orders by the late April 2018 time frame, depending on parts availability and manufacturing time. All final Manufacturing will be done at Halcyon Modular in Portland, Oregon, USA. Check the Updates as the campaign progresses for any schedule changes.

Specifications:

Width: 16HP ( 80.6mm)

Height: 128.5 mm (Doepfer standard)

Depth: 35mm (Front panel to the rear tip of the power connector)

Weight : 0.4 kilograms (in box with packing and cable/screws)

Panel: 2mm thick (Aluminium finish)

Silk Screen: Black

Power connector : Keyed, 16-pin Eurorack, ERA compatible

Power Consumption: +12V, 40mA, -12V 32mA

V/Octave Scaling : 1V/Octave

Frequencies : Tri/Ramp/Pulse : ~20Hz to ~22kHz

Suboctave1 : ~10Hz to ~11kHz

Suboctave2 : ~5Hz to ~5.5kHz

Suboctave1 : ~10Hz to ~11kHz Suboctave2 : ~5Hz to ~5.5kHz Output Range : Tri/Ramp/Pulse : +/-5.0 Volts (Bipolar)

Suboctave1/2 : 0.0 - 5.0 Volts (Unipolar)

Suboctave1/2 : 0.0 - 5.0 Volts (Unipolar) Input Range* : Volt/Octave A/B : 0.0 - 8.0 Volts (Unipolar)

FM Inputs A/B : +/-5.0 Volts (Bipolar)

PWM Inputs A/B : +/-5.0 Volts (Bipolar)

Sync Inputs A/B : +/-5.0 Volts (Bipolar)

Lock Inputs A/B : +/-5.0 Volts (Bipolar)

(* - Actual/Effective range is determined by the V3340D itself)

FM Inputs A/B : +/-5.0 Volts (Bipolar) PWM Inputs A/B : +/-5.0 Volts (Bipolar) Sync Inputs A/B : +/-5.0 Volts (Bipolar) Lock Inputs A/B : +/-5.0 Volts (Bipolar) (* - Actual/Effective range is determined by the V3340D itself) I/O Jacks: Monophonic, 3.5mm Jack (Doepfer standard)

More Demo Tracks :