AEMIT Presents Innovative Eurorack Modules for the Discerning Synthesist

AEMIT ~ Some Sound Snippets from Aemit modular on Vimeo.
AEMIT - Formant tests with System 7.5


AEMIT ~ Variphase babbling from Aemit modular on Vimeo.


AEMIT ~ Fluxus making things roll from Aemit modular on Vimeo.

AEMIT ~ Quad sync from Aemit modular on Vimeo.

4x VCO II syncing each other, with Variphase modulating the whole bunch.

AEMIT ~ VCO II drone from Aemit modular on Vimeo.

Variphase with 3 outputs detuned to a chord + 2 VCO IIs an octave above and below the Variphase root note. All of that into 2 EVC filters, lots of resonance, slow LFO on the spread on the EVC+ expander.

AEMIT ~ TWO LFOs wavemorph chaos from Aemit modular on Vimeo.

Morphing of LFO A's wave, LFO B is slaved and reset randomly. Playing with the div/mult factors of both.

You might remember the name AEMIT from this one of a kind modular system posted back in 2009 (and in 2006). I asked AEMIT if this new system was in any way related and indeed it is! Guy Drieghe-D covers the design, Wim Verheyen covers engineering, and Didah Drieghe-D covers marketing, sales, and prototyping. The VCO II is a modern upgraded version of the original VCO, while the other modules are brand new concepts and designs.

The official press release follows.

"AEMIT is proud to announce the world premiere of our high-end range of new Eurorack modules at Superbooth19, in Berlin.

No less than ten different modules (listed below) will be shown in our System 7.5, a 104HP powered skiff with two rows of 3U and one utility strip of 1.5U, the latter being a new subframe standard as proposed by AEMIT.

While the AEMIT name might be new to the outside world, we actually built our first one-off modular synthesizer in 1982, which is still in operation today. Its main principles of no-compromise functionality and outstanding usability are carried over to the new Eurorack system, in development since 2017.

AEMIT modules conform to a WYSIWYG single-function design, with a strong focus on voltage-controlled access to all possible parameters, a very wide operational range, and convenience of use. Our no-nonsense approach to synthesis is build upon decades of experience in both soft- and hardware development and user-interface design. Though rather conventional in looks — not necessarily a bad thing, the AEMIT experience offers extraordinary possibilities with unique functionality not available anywhere else, inviting the intrepid musician to “boldly go where no synthesist has gone before”…

Next to our full system, ready to be tested & heard at Superbooth19, there’s a lot more brewing in the near future…

Availability

Some AEMIT modules will be available by mid-Summer ’19, at exclusive world-wide dealerships.
Follow-up modules will be released in Autumn ’19.
The System 7.5 skiff with built-in 1.5U Utility Strips and superior power management is expected to be released by year’s end.

System 7.5 listing

• VCO II - Your daily workhorse analog Oscillator and LFO, with generous in- and outputs.
• Variphase - Variable Phase Oscillator and LFO, with variable waveform, pitch & phase per output (5).
• EVC Filter - 4-pole 24dB/Oct State Variable Filter, with voltage control over Fc, Q, Slope & State.

• EVC+ - Expander to the EVC, linking two EVCs and adding voltage control over Routing.
• Quadsum A - Four-channel voltage-controlled Audio Mixer & polarizer, with optional 3dB gain (soft-clipped).
• Quadsum L - Identical to the -A version, adjusted for linear CV duties.
• QS+ - Expander for both Quadsum, turning them into full-blown quad VCA’s, and adding VC-Summing.
• Two Gates - Dual analog VCA, one of which has voltage control over its Response.
• Two LFOs - Innovative dual wide-ranged VC-LFO, with extensive syncing & tracking possibilities, and div/mult clocking.
• Fluxus - Variable Slope Multistage Transient Generator, with optional self-cycling, and voltage control over Timings.

• 1.5U Utility Strips offer clever 3-trunk multiples, buffered mults, 3-ch Mixers with offset, Inverters, Polarizers, dual LFOs, vc-Slew generator, stepped & smooth Random generator, and an AD Envelope. The additional Exit module takes care of line level outputs with signal/overload indicators, headphone output, and a handy Mute switch.

Please visit our web site for more info & detailed specifications.
www.aemit.be
"



The line-up for the MATRIXSYNTH archives (P.S. Love the Buchla style knobs and aesthetic on eurorack!):

"VARIPHASE
Variable phase oscillator & lfo.

ÆMIT's experimentation lab is equipped with a quad speaker system, so we needed something to swirl those sounds around. Not content with a relatively simple quadrature oscillator, the Variphase quickly evolved into a polyvalent beast of epic proportions (excuse the hyperbole). Not your average oscillator this then.

In addition to a fixed 0° output, there's four separate outputs at either fixed quadrature phase, or adjustable phases equally & dynamically spread over a very wide range. A powerful mix output blends the 0° waveform with any other phase, taking care of your basic waveshaping needs.
Each output can produce a different waveform, and can be individually detuned against the 0° output. Yup, 5-note chords indeed, made easier to tune by activating its optional quantization function.

In the ÆMIT tradition everything needs to be voltage-controlled. So, obviously there's your obligatory exponential FM input and its 1V/Oct cousin, as well as a linear thru-zero FM input, a phase modulation input, and a 4-quadrant AM input for those lovely bell tones. Or screeching mayhem.
A sync input completes the picture.

The basic properties of the Variphase are nothing to sneeze at either.
An overall frequency range of 26 octaves, split up over 3 range bands. Pitch-perfect tracking over more than 12 octaves. Optional quantized tuning and frequency modulation.
Auto-saving of all settings at power-down, and auto-reloading at power-up. Resettable to a default state in case you got lost in its endless possibilities.
It operates at super high resolution with no aliasing whatsoever, and is completely jitter- and noise free. The Variphase core runs at zero latency, which allows for the elusive self-feedback patches.

So there it is, a single digital oscillator capable of mimicking an entire analogue powerhouse. With the accent on analogue.

The Variphase pairs well with our VCO II. Or with another Variphase. Or both.
Specifications

Variable phase, 0º, 90º, 180º and 270º outputs, each with selectable waveform.
Mix output combines 0º and variable phase outputs.
Selectable waveforms : Sine, Triangle, Saw, Ramp,Square, and Pulse.
Phase Modulation from -360º to 360º on var output.
Equal Spread phase modulation on es-a, es-b, and es-c outputs, providing up to +/- 720º, 1080º, 1440º respectively and simultaneously.
Linear thru-zero FM input with attenuator.
Exponential FM input, can be quantised in semitones.
4-quadrant AM input, with attenuator & initial gain control.
1V/oct input; 12 octaves perfect tracking (audio range), overall range is 26 octaves.
Full Audio range : 5Hz - 20kHz
Low range : 0.05 (20 sec) - 200Hz
Sub range : 0.0005 (33min) - 2Hz
Detune Interval and detune Fine Hz (constant detune over the whole frequency range) on each phase output with center dead-band. This allows 5-note chords to be played. Detune interval can be quantised in just intonation steps over + and - 1 octave.
Sync input (hard).

All modulations from DC to 20kHz.
Zero latency allows for feedback patches.
All settings and detunings are automatically saved when powered off, and restored when powered on again.
Full 16-bit resolution, anti-aliased waveforms, no distortion.

Skiff friendly : 41mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

16hp
120mA +12V, 35mA -12V, 0mA 5V"

VCO II
Your daily workhorse oscillator or LFO.

Fully analogue CEM3340 design, based on our proven 1982 vintage VCO.
Wide-ranged, yet easily tunable thanks to its clever Range/Span switch combo.
Extremely stable & drift-free, with rock solid tracking over at least 8 octaves.

Outputs a clean Sine, plus five other waveforms, simultaneously.

It has a ton of controllable cv inputs, so you'll never run short on modulation possibilities.
Two exponential FM inputs, one of which has a bipolar control. A linear FM input is available as well, and two 1V/Oct inputs give you the possibility to transpose your sequences. The obligatory PWM input is at your disposal too, so you can generate ultra fat sounds with our unique pulsaw waveform.
Soft- and hard sync inputs are available at the same time, for those moments when utter screaming mayhem seems the right thing to do.

Switch it to Low Range so you can modulate your other VCO II's in 45 second cycles, if things need to go real slow. Though you can push the LFO into shattering bass territory as well.

Given its affordability, polished behaviour and good looks, we think you'll need three of these.
Specifications

Original vintage 1982 design adapted to Eurorack.
Audio range : 5Hz - 22kHz (@ 12V input, absolute max is 40 kHz).
Low range : 45sec. - 100Hz (@ 12V input, absolute max is 170 Hz).
1V/oct input, tracks over 8 octaves (5Hz to 5kHz).
Linear FM input with attenuator.
3 FM inputs with attenuators, 1 is bipolar, 1 is linear.
Span lower sets coarse pot for lowest 6 octaves, span upper sets coarse pot for highest 6 octaves, with an overlap of 1/2 octave.
Fine tune (12 semitones range).
Pulse Width adjustable from 5 to 95%.
PWM with input jack and attenuator.
PW affects both Pulse and "Pulsaw" outputs.
Individual outputs for Saw, Ramp, "Pulsaw", Pulse, Triangle & Sine, low impedance, 10Vpp.
Soft and Hard Sync inputs, can be used simultaneously.

Skiff friendly : 31mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

16hp
50mA +12V, 35mA -12V, 0mA 5V

TWO LFOs
Dual Voltage Controlled Low Frequency Oscillators.

Who'd ever thought the humble LFO could be transformed into such a powerful multi-talented tool ?

ÆMIT has designed a dual voltage-controlled low frequency oscillator with unparalleled synchronization possibilities, and a slew of other clever features which will most certainly revive interest in this somewhat forgotten bastard child of the oscillator.
Both LFOs boast a very wide frequency range, easily going from 16 minutes per cycle to well into audio territory. Voltage-controlled rate, externally resettable waveforms (hard sync), and selectable unipolar or bipolar outputs are common to both as well.

LFO A features a variable waveform output - morphing from sine to square - which is, needless to say, under full voltage-control.
LFO B has selectable waveform outputs, and features an extra random output. While lacking the morphing ability, LFO B offers a built-in VCA instead, which makes the separate sum output (a+b) all the more powerful.

LFO A can be clocked externally, either by listening to any incoming signal, or by manually tapping a tempo. In either case, the LFO's rate can then be dialed into a musical division- or multiplication of the external clock. This unique ability makes this LFO sit comfortably within any rhythmic chain of a modular synth.
LFO B can be slaved - or synced, if you so wish - to LFO A's internal or external clock, and derive a division or multiplication of it. By doing so, LFO B can effectively follow any external signal too, and do that in a musically meaningful way.

Because LFO B's cv inputs - fm and am - are normalised to LFO A's output, it becomes easy to create more complex waveforms and rhythmic variations to simulate thrillers, arpeggios, accelerandos & decelerandos, note bursts and bouncing ball events.

We like to think of TWO LFOs as the first (and perhaps only) linear modulation source which truly deserves a well-earned place amongst the generally more accepted modules like VCOs and the like… It just blends in naturally, and makes itself quickly indispensable in any mature modular synth setup.

Pairs well with anything that can be modulated. :-)
Specifications

LFO A :
Continuous VC Morphing between Sine, Triangle, Saw and Square waveforms.
Pulse output with variable pulse width.
Internal mode : internal oscillator with exponential FM.
Listen mode : external listen input with threshold, sampled/held or tracked with multiply/divide.
Tap mode : tap tempo with multiply/divide.
In Listen and Tap mode, FM works as phase shift.

LFO B :
Selectable waveforms : Sine, Triangle, Saw, Ramp and Square, plus Stepped Random.
Waveforms can be sequenced @ Rate/Ratio speed.
A+B output : output A plus a voltage-controlled portion of output B
Internal mode : internal oscillator with exponental FM.
Slave mode : follow LFO A with multiply/divide.
In Slave mode, FM works as phase shift.
AM and FM inputs normalled to output of LFO A.

Common to both :
Output is selectable to be bipolar or unipolar.
Lo range : 0,001 (16min) - 1Hz
Hi range : 0,1 (10 sec) - 100Hz (1600Hz with multiply * 16)
Lfo range : 0,2 (5 sec) - 20Hz; fine control thanks to the limited range of 100:1
Multiply/divide uses 1/4 note as default, range is from 1/64 note to 4 whole notes with dotted notes and triplets.
Reset input (hard sync).

All settings are automatically saved when powered off, and restored when powered on again.
Skiff friendly : 41mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

16hp
tba +12V, tba -12V, 0mA 5V

EVC FILTER
24dB State Variable Filter.

EVC is an acronym for "Everything Voltage Controlled", one of the core ideas at Aemit.
The EVC Filter is a truly revolutionary design, which encourages the fearless user to unlock a Pandora's box of previously unexplored sonic territories.

At its heart, the EVC Filter is a 4-pole 24dB/Oct State Variable filter, with simultaneous lowpass, highpass and bandpass outputs and a separate variable state output as well. Since the EVC Filter can operate in both audio and sub-audio range, its two signal inputs are DC-coupled. One of those inputs has automatic gain control, keeping your output levels in check when working with high-Q settings.

When we say "EVC+", we mean it.
Obviously its cutoff frequency is voltage controlled, with a 1V/Oct input (the EVC Filter tracks quite well when used as an oscillator) and two exponential fm inputs, one of which has a bipolar control. Note that the EVC has both coarse and fine tune knobs, for when precision tuning is required. Resonance goes up to self-oscillation, and is under voltage control as well.
The EVC's slope can vary between 6dB and 24dB and anything in between. This can be done manually, and under voltage control. Voltage controlled Slope. Yes, sir. The EVC's state can vary between LP, BR (or Notch) and HP, and anything in between. This can be done manually, and under voltage control. Voltage controlled State. Yes, ma'am.

There is no other [hardware] filter in the world which can do this.
While we're at it, let us remind you that the EVC filter is fully analogue.

A good synthesizer filter must have body and soul, of which the EVC Filter has plenty, but a truly standout filter must also possess its own character, often making it instantly recognizable amongst its peers. Our filter imposes its unique and easily identifiable character by giving the user control over how resonance is handled, through means of a peaking control. When set to "twin peaks", the filter will behave and sound like it is nearly oscillating, but it will actually never burst into self-oscillation, giving the user enough confidence to seek and explore the outer limits without actually blowing up anything.

All good things come in pairs, goes the saying, and the EVC Filter is no exception to that.
When hooked up to the optional EVC+ expander (and a second EVC Filter, obviously), you gain additional [voltage] control over both cutoff frequencies at once, instantly enabling exotic possibilities like bandwidth-controlled 24dB Bandpass superiority, or pseudo-formant filtering. Most dual filter designs allow you to switch between serial and parallel routing, but Aemit decided to up the ante, and thus offers full voltage control over routing, thereby opening up uncharted um, routes to sonic bliss.

EVC Filter pairs well with any source of complex waveforms like our VCO II or Variphase, but pairs equally well with another EVC Filter.

Specifications EVC Filter

LP (24dB), HP (24dB), BP (12dB) and Variable outputs.
Audio range and Low (DC) range.
Two Signal inputs with attenuator; Automatic Gain Control on input 1. Input 2 can be overdriven, with soft clipping.
Two FM inputs with attenuator, 1 is bipolar.
1V/oct input, tracks ±6 octaves.
Voltage controlled Resonance (Q), up to self-oscillation.
Voltage controlled Slope from 6dB to 24dB per octave.
Voltage controlled State : from LP over Notch to HP.
Bandpass switch.
Double Peaking control (suppresses self-oscillation).
Fine Tune control for Cutoff frequency.

Fully analog architecture.

Skiff friendly : 41mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

16hp
tba +12V, tba -12V, 0mA 5V
Specifications EVC+

Optional. Requires 2nd EVC Filter.
Master Cutoff frequency control; controls both frequencies simultaneously.
Master CV input with attenuator.
Spread CV input with bipolar attenuator; shifts both frequencies in opposite directions.
Voltage controlled Routing : Parallel to Series.
Routing CV input with attenuator.
Trim control for Filter 2, when in series.
Switch to disable Routing.

Skiff friendly : 41mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

8hp
tba +12V, tba -12V, 0mA 5V

FLUXUS
Variable Slope Multistage Transient Generator.

From Latin: flowing, fluid, loose, transient.
Traditional envelope generators, often abbreviated to the incredibly original ADSR acronym, fall short when it comes to emulating amplitude envelopes of acoustic instruments, more specifically struck- and blown instruments. Thus the need for a transient generator able to cope with more complex envelopes led to the design & development of Fluxus, aka the Variable Slope Multistage Transient Generator.

When initiated (e.g. by a gate signal), the transient will move from zero to a certain level within a given time. This is the onset time, similar to the attack time of a traditional envelope generator. Next, the transient moves to yet another level with its own timing. This could be seen as a "post-attack” or "pre-decay” stage, but that would be too limiting a term. Once completed, the transient moves on to the next level, again with its own timing, and stays there as long as the gate remains high. This is the same as a sustain. When the gate is removed, the transient will move on to zero within a given time, finishing one transient cycle. This last stage is the same as a release.

Explained in another way, Fluxus does much the same as a classic ADSR, but without the limitations of the attack level always being at maximum (8- to 10V), and the decay time starting immediately after the attack. Another major difference is that the decay start level does not necessarily sit at maximum. Even more, the decay can rise instead of fall to the sustain level, depending on the level settings.

Both timings and levels can be voltage controlled with a bipolar controller. When fully opened, the timing cv will track 1V/Oct.

Most rising and falling stages of amplitude- and timbre envelopes do not move through time in a linear fashion, but rather in a logarithmic or exponential way. Thus Fluxus has the ability to sculpt each timing slope individually from log over linear to exponential, or anything in between. Notice that timings do not change when adjusting the curves.

As far as "punchy envelopes" go, we believe Fluxus has raised the bar somewhat by having a minimum timing of 0.1ms per slope. That's ten times faster than even the fastest colleagues out there. At the other end of the scale, a slope's maximum time can be as much as almost two minutes.

Fluxus gives the user full control over how [re]triggering is handled. Legato or staccato keyboard playing can be dealt with in several ways, and adjusted to taste.

Because recurring envelopes in acoustic instruments or "natural sounds" in general rarely repeat in exactly the same, machine-like manner, Fluxus can introduce some jitter (randomness) in the timings and levels, at various degrees. Introducing just a little bit of jitter emulates a more human feel to rhythmic envelopes.

A trigger output makes it possible to synchronize another Fluxus (or any other trigger-able device) to the endpoint of any stage, or even to the internal clock.

One more thing.

Cycle mode.
And it comes in three flavours. Either in self-running mode, where cycle frequency is dictated by a rate control, with time proportionally defined by the time settings. Or in auto-run mode, where the cycling frequency is dictated by the time settings (rate control is ignored). And lastly in gated-mode, which does the same as self-cycling, but only when a gate is present.
So, with the flick of a switch you're running a sophisticated transient generator with- or without auto repeat, a standalone oscillator/LFO with waveshaping capabilities, or a burst generator.
Depending on the cycle mode setting - including no cycling, the time & level cv inputs yield different results. When not cycling and in auto-cycling mode, these inputs can be seen as keyboard tracking and velocity controls, while in cycling-mode they’re acting like timbre- and waveshaping controls. Imagine the possibilities.

Due to its characteristic user interface, Fluxus supports both the more traditional approach to envelope generation, as a somewhat more experimental approach. It's as easy to set it up as a classic ADSR or AD generator (by patching the trigger out to the retrigger in), as it is to come up with unreal and unique envelopes. The latter only requires a bit of out-of-the-box thinking, which Fluxus manages to encourage quite well, we feel.
Specifications

Stage 1 starts when Gate goes on, from 0 to Level 1 during Time 1.
Stage 2 : From Level 1 to Level 2 during Time 2.
Stage 3 : From Level 2 to Level 3 during Time 3.
Stage 4 (Sustain) : remains at Level 3 as long as Gate is on.
Stage 5 (Release) : Starts when Gate goes off, from Level 3 to 0 during Time 4.
Each stage except Sustain moves from one Level to the next along a logarithmic, linear, exponential or any curve in between as set by the curve controls.
Scale button can set four ranges for Time controls :0.1ms…1s, 0.8ms…8s, 2ms…20s, 10ms…100s.
Times CV input (1V/oct) with bipolar control modifies all Time settings.
Levels from 0 to 10 V.
Levels CV input with bipolar control modifies all Level settings.
Dual unipolar envelope outputs.
Bipolar output (best used when in Cycle mode, as a VCO/LFO).
Trigger output, configurable to fire at any EOT, or Rate clock.
Gate input (accepts any signal).
Manual Gate button (momentary).
[Re]Trigger input: configurable to restart from Stages 1, 2 or 3.
Retrigger Modes: Off (ignores Trigger input), Reset (keeps current level and continues from there), Zero (resets level to start level and continues from there).
Cycle Modes:
Self: cycle time dictated by Rate control, with time proportionally defined by Time settings.
Gated: same as Self, but cycles only when Gate is on.
Auto: cycle time depends on Time settings; Rate control is ignored.

All settings are automatically saved when powered off, and restored when powered on again.
Skiff friendly : 41mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

16hp
tba +12V, tba -12V, 0mA 5V

TWO GATES
Dual Voltage Controlled Amplifier.

With our dual analogue VCA design, we just made the second-most boring module in a modular setup a whole lot less boring.

Basically the top VCA lends itself best for regular VCA & mixing duties, while the bottom version allows for more precise control to massage a single signal. Both feature a clean noise-free signal path, with lots of headroom to spare. Signal and modulation inputs are DC-coupled, with zero bleed-through for the cv's.
The top VCA features two controllable signal inputs, one controllable am input, and a switch to set the response to either linear or exponential. A VCA isn't a proper one without an initial gain control, thus we've got that covered too.

The bottom VCA offers only one signal input, but with a bipolar level control enabling the inversion of any incoming signal. Two modulation inputs, one of which has a bipolar control, give you the opportunity to apply an amplitude envelope and add some tremolo while you're at it. Or two envelopes, why not ? The post-fader modulation signals and the initial gain setting are combined and made available at a cv mix output, so you can pass on the same modulation to a second VCA or other destination.

Perhaps the most outstanding aspect of the bottom VCA is the uncanny ability to have full voltage control over its response curve. A typical application for this unique feature would be to shorten or lengthen the timing of a controlling envelope, and setting pseudo-accents according to the incoming response cv, though many other applications beg to be explored.

The importance of plenty VCA's in a complex modular system can't be stressed enough, and we like to think that our Two Gates is more than able to fulfil that role under any and all circumstances…
Two Gates might look deceivingly plain-vanilla, but make no mistake, this is really proper VCA goodness.

Two Gates pairs well with, umm, with anything and everything.
Specifications

TOP VCA :
Two signal inputs with attenuator.
AM input with attenuator.
Initial Gain control.
Linear or Exponential response switch;
Exponential response has 15dB extra headroom.
Linear gain response is 10%/V
Exponential gain response is 10dB/V (starting at -100dB @ 0V).
VCA is off (-100dB) @ 0V control voltage, unity gain (0dB) @ 10V control voltage.
Frequency response : DC to 20kHz for both signal and modulation.
Output with bicolor signal indication LED.

BOTTOM VCA :
Signal input with bipolar attenuator.
Two AM inputs with attenuator, one is bipolar.
Initial Gain control.
Voltage controlled Linear to Exponential control;
Exponential response has 11dB extra headroom.
Linear gain response is 10%/V
Exponential gain response is 10dB/V (starting at -100dB @ 0V).
VCA is off (-100dB) @ 0V control voltage, unity gain (0dB) @ 10V control voltage.
Response CV input with bipolar attenuator.
Response is linear @ 0V control voltage, response is exponential @ 10V control voltage.
Initial response control.
Frequency response : DC to 20kHz for both signal and modulation.
Dual output with bicolor signal indication LED.
CV Mix out : mix of AM inputs and Initial Gain.

Fully analog signal & cv paths.
Skiff friendly : 31mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

16hp
50mA +12V, 40mA -12V, 0mA 5V

QUADSUM
Four-Channel Voltage Controlled Mixer, Quad VCA.

Our four channel voltage-controlled mixer (and quad VCA) comes in two versions.
The linear version — blue sum level knob — is ideally suited for cv mixing duties, whilst the exponential version — red knob — performs best with audio applications.

Two channels have unipolar attenuators for both signal and cv inputs, with the remaining two other channels having bipolar controls (aka "attenuverters") for signal and cv. Use the former channels when you absolutely need precise control over signals, and use the latter when inversions and shifting and mangling is what you seek.

At the 3'o'clock position the sum level control knob is at unity gain; beyond that it goes into overdrive mode, adding 3dB of gain, with a smooth soft-clipping limiter behind it to keep your signals in check.

In case you need more than four channels, simply plug in another Quadsum to the auxiliary input.

An optional QS+ expander module transforms the Quadsum into a full-blown quad VCA, by making the individual outputs of each channel available.
The sum level gains (no pun) a control input too, enabling amplitude control over all four channels simultaneously.

Additionally, one can create a four-channel post-fader submix of the Quadsum outputs. This comes in handy when you'd like to have two differently balanced versions of the same mix and send them off to separate signal flows. Or simply send the submix output back to the auxiliary input of Quadsum for some good old feedback fun.

Quadsum is an excellent companion to our Variphase and VCO II oscillators, but of course it can be deployed to good use anywhere in a modular system as well.
Specifications Quadsum

Available in Exponential (audio) and Linear (cv) versions.
Per channel :
Signal input with attenuator; bipolar on channels 3 and 4.
Voltage control input with attenuator; bipolar on channels 3 and 4.
Initial level control.
Gain response is 10dB/V (starting at -100dB @ 0V).
Channel is off @ 0V control voltage, unity gain @ 10V control voltage.
Frequency response : DC to 20kHz for both signal and modulation.
Bicolor signal indication LED.

Auxiliary input for cascading Quadsums.
Sum level control with 3dB overdrive and soft-clipping limiter.
Dual Sum outputs with overload LEDs.

Fully analog signal & cv paths.
Skiff friendly : 41mm deep behind front panel, including power header.
Shrouded header on the power supply connector, no risk for reverse polarity.
Includes printed manual and power cable.

16hp
tba +12V, tba -12V, 0mA 5V
Specifications QS+

Optional. Works for both audio & linear versions of Quadsum.
Individual channel outputs(turns Quadsum into a fullblown quad VCA).
Sum Level control input with attenuator.
Postfade 4-ch submix of Quadsum outputs.
Submix output.

Skiff friendly : 21mm deep behind front panel.
Includes printed manual and power cable.

8hp
Powered by a Quadsum.