MAQ16/3 FracRak Breakout Box

MAQ 16/3 FracRak breakout panels

Not every-one finds it practical that the Doepfer MAQ16/3 Sequencer has all its connections on the backside of the module.
Especially when you change your setup a lot, you don't want to climb behind your 19"-rack to change patch-cables every time.

Of course there are always people who have figured out a solution for this.

This MAQ breakout panel that i found in an old Matrixsynth post came with a pair of custom made FracRak breakout panels to bring the MIDI jacks and the 1/8" Voltage Control and Gate jacks to the front of your FracRak panel for easy patching.
These would have fit perfectly next to your Paia modules for example.
It also had the necessary cables to connect to these panels from the back of the MAQ16/3.

Sideview of theMAQ 16/3 FracRak
breakout panels

According to the maker these panels were not cheap to put together. (Try pricing the 2 MIDI panel mount barrels and even the 6 panel mount 1/8" barrels)

Theoretically it is possible to make such breakout panels for a Eurorack system.

The CV and Gate outputs would fit easily on one of those 8HP wide pre-drilled blank panels (A-180-style) that Doepfer sells as spare parts. 

You can even put in a few extra switches for your own maximized customization experience. Your limit is your imagination.

Personally, I have long CV (red coded cables) and Gate (blue) wires coming out of my MAQ16/3 that come into my Eurorack system through multiple A-180 Multiples modules, but i can see the benefits of this module.

It might be worth investigating the possibilities of a Eurorack breakout panel a little more for a future blogpost.

A-166 Dual Logic Module

" A Logic Gate is an idealized or physical device implementing a Boolean function.
It performs a logical operation on one or more logic inputs and produces a single logic output. Logic gates are primarily implemented using diodes or transistors acting as electronic switches. "

The A-166 Dual Logic Module is a double logic device that combines digital control / clock signals.
A typical application of this module is the combination of digital signals of the A-100 gates, clocks and triggers to obtain "gated" clocks or rhythmic clock patterns.

It contains 2 identical units with 3 inputs for each unit.
The logical states of the inputs ("1" = high / "0" = low) are linked together in 3 ways: AND, OR, EXOR (exclusive OR).
The input sockets of each triple unit are "normalized", i.e. the switched contact of socket 2 is connected to input 1 and the switched contact of socket 3 is connected to input 2.
The three functions are available simultaneously at three outputs with LED display of the output states.

Additionally two separate inverters ( like the A-165  ) are available that are very useful.
These can even be used to invert a signal before it is fed into one of the two logical units.
All other outputs can be fed back to the module's inputs also... in that way you can create very nice and very complex rhythmic triggers.

More on Logic Gates on Wikipedia

...and on Whatis.com

CV / Gate Cable Length

A few times I've been asked about how patch-cable lengths ( of CV and/or Gate signals ) can affect signal strength.
I found a few interesting posts in the Yahoo Doepfer Usergroup that might make things a bit clear to you.

First of all;
Gate cables even longer than 10 meters usually are no problem.
Although a gate signal might get slightly weaker when you use extremely long cables, the (simple) gate signal will often stay strong enough to trigger your modules.
CV-Cables of this length may have a slight loss depending on the electrical characteristics of the input and the output.
There are ways to measure it,  but it is very difficult to judge whether a not completely clean octave tracking is caused by long cables.
Real loss of signal quality starts with asymmetric audio cables at such a length, and you have always to keep in mind that electromagnetic and electrostatic influences (hum and sizzle) can affect longer cables more than shorter cables.

" From a theoretical point of view (for anyone interested) the key things are output and input impedance, cable capacitance and resistance.
If you take a relatively standard low-cost coax cable of say 380pF/m and 128 Ohms/km this will not cause any noticeable loss in audio top-end from a 1k Ohm output impedance until you exceed 20m or so but you are more likely to get increased noise and interference.

From a CV point of view the cable resistance is a more important parameter (if your CV is controlling VCOs that is) but even 20m is only 2.6 Ohms so this can be ignored compared to the high input impedance of most VCO CV inputs; again long lengths are more prone to pickup so 50Hz mains can modulate the CV.
( you may also experience hum loops by just connecting gear together that is powered from different power outlets across the room ). " *

( * thanks to Tony Steventon from Synovatron for the 2nd half of this post )

Using the A-100 for Sound Processing

A-119 External Input /
Envelope Follower

The A-119 External Input / Envelope Follower module allows you to integrate any audio signal (electric guitar, microphone, midi sound module, computer sound card, CD player, tape-recorder ...) into your A-100 system.

Audio inputs of audio-processing A-100 modules (e.g. filter, VCA, phaser, flanger, waveform processor, distortion, wave multiplier, ring modulator, frequency shifter, spring reverb, panning ...) all require line level signals of around 1Vss. , and if the signal source does not have the required level an external pre-amplifier like the A-119 is recommended. 

This module consists of a (pre-)amplifier, an envelope follower and a comparator.

The pre-amp has 2 inputs, one unbalanced (Asymmetric) for line level signals, and a balanced (6.3mm jack /Symmetric) input for inserting low level signals, like microphones or electric guitars.
The module provides two simultaneous audio outputs of the amplified signal.

The envelope follower 'reads' an incoming audio-signal and sends out a proportional voltage as an envelope to its own output.
The brightness of the LED indicates the envelope output level, which is very useful...

The voltage at the output signal can be used to control the filter frequency, loudness or any other voltage controlled parameters such as filter resonance, LFO speed, clipping level, wave multiples, frequency shift, phase shift, delay time and more...

The comparator generates Gate signals out of the incoming signal.

Whenever the audio input exceeds a certain (adjustable) level, a Gate-signal is produced.

This signal can again be used to trigger various other external modules like envelope generators or even voltage controlled switching.

Again, this is a very useful module that i cannot do without anymore because i often use external audio inputs. Most of the times i have a microphone plugged in for vocoder use or for filtering pleasures, but i have used it with my guitar and other audio too.
I do find it a bit strange that it is not included in one of Doepfer's pre-configured basic systems, for me it was a must-have.

A-101-2 Vactrol Low Pass Gate

I must say i am very happy with my latest module, the A-101-2 Vactrol Low Pass Gate.
This module is a combination of a 12dB Low-Pass Filter and a Voltage Controlled Amplifier (VCA), with 2 vactrols as controlling elements with very unique characteristics and is very popular amongst the members of the Doepfer A-100 Yahoo Users Group.

The module is based on the Buchla Model 292 Quad Voltage-Controlled Lopass Gate module. '
The term "Low Pass Gate" was first used by Don Buchla for a module that can be switched between Low-Pass and VCA.
Buchla's current (2004) update is the Model 292e Quad Dynamics Manager ,that is functionally identical to the older model, but includes some extra functions like velocity inputs, allowing controllers to control note volumes with performance gestures and preset storage.

Doepfer's LPG module can handle 2 different incoming control voltages that can be used to control the Low-Pass filter, or to open or close the VCA.
Additionally a combined mode LP + VCA is available which makes the sound more dull as the loudness decreases. This is characteristic of all acoustic instruments (the harder you strike, pluck, or bow, the richer the overtone structure), but had been lacking in electronic instrumentation before..

In contrast to the Buchla design the A-101-2 offers attenuators for both CV and audio input, a manual resonance control and two gate inputs to control the function of the module in addition to the manual toggle switch.
The filter is hard to describe, but vactrols are known for their smooth sound behavior. Compared to a 'normal' 12 dB filter like the Low-Pass filter from the A-121, they sound quite the same, but the Vactrol inside the A-101-2 does give it a smoother edge that can perhaps best be compared with a very subtle 'slew' effect. The VCA has that same 'slewy' characteristic, but doesn't sound dramatically different than a regular VCA to my ears.

The combination of the LPG and VCA, is (obviously) my favorite setting and with the resonance up this module really starts to shine. ( Resonance is adjustable all the way up to self-oscillation )

A nice extra are the 2 Gate inputs, that can make you ( rhythmically ) switch between the two functions of the module with an external sequencer or other triggers. I'm not sure if 2 Gate inputs was necessary though.., personally i had rather seen an extra CV input for the Resonance (QCV) for example.
(Perhaps this can be modified?)

Overall this is a very nice-sounding module, that i will use a lot in the near future. I'm not sure if i put it in my top-5 list of favorite modules, but it will at least be in my top 10 for the next few months.

- Check my earlier Vactrol Basics post for more general details about vactrols,
or take a  look at Doepfer's Vactrol Basics page.
More about the A-101-2 LPG  including an audio example at Andreas Krebs blog

A-178 Theremin Control Voltage Source

The Theremin, invented in the late 1920's by Léon Theremin was one of the earliest electronic instruments.
The instrument is known for it's distinctive ( spooky ) sound, but most of all for it's playing method; Instead of playing it with a keyboard, the Theremin has antennas that sense the movement of the players hand, without touching the instrument.
Best known for playing the Theremin is Clara Rockmore, one of Theremins finest students.

Most theremins use two antennas, usually one for pitch and one for volume, so with two Doepfer A-178 Theremin Voltage Source modules, an oscillator (VCO) and an amplifier (VCA) module, it is quite easy to re-create the sound of a 'real' Theremin. You can even easily extend that sound by patching in filters or other modules.

And again, that is what makes the A-100 modular so versatile. 

Instead of just recreating the original Theremin you can use the module as a control voltage source for other modules. 

The voltages can be used for controlling any voltage controlled parameter of the A-100, e.g. pitch or pulsewidth (VCO A-110/111), loudness (VCA A-130/131/132), panning (A-134), filter frequency or resonance from all of the filter modules, phasing (A-125), frequency shift (A-126), resonance peaks (A-127), envelope parameters (A-141/142), and tempo (A-147), to name just a few ;-)

The Gate-output with adjustable threshold (not available on the original Theremin) is a nice extra output. I often use this for (re-) triggering notes or filter effects, but it can also be used for starting sequences (A-155) or for reset or switching functions (A-152).

Doepfer recommends if two or more A-178 are used the distance between the modules/antennas should be at least 30 cm to avoid interference.

Most wanted III - DIN Sync

The DIN Sync (or Sync24) standard, was introduced by Roland in the 80's for synchronizing sequencers, drummachines and (synth-) arpeggiators. The name Sync24 is derived from the frequency of the pulses, 24 pulses per quarter note (PPQN). A clock signal  of 2.51 V, at 24PPQN, defines the speed of the sequence or drum pattern. The start/stop signal defines if the sequence is running and has a voltage of 0 or +5 Volts. A lot of Roland's products were using this standard at the time, so some have sync-in, -out, or switchable sockets.

After the wide adaptation of the MIDI standard, the DIN sockets started to dissapear from most instruments. Syncing instruments via MIDI is now handled by the MIDI Beat Clock at a same 24 PPQN rate.

The SYNC plugs look the same as MIDI plugs ( DIN-standard, round with 5 pins ) ,but the pins have a different configuration as the MIDI plugs. The Din Sync standard can only handle clock signals (for tempo) and start/stop signal, so it sends no pitch-control. More info on Doepfer's SYNC FAQ page.

I know the DIN-Sync standard is now close to death. Only a few 'modern' drum-machines still have a SYNC In or Out, like for example the Novation Drumstation that i own.

The idea of a A-100 SYNC converter module doesn't sound bad in my opinion, perhaps a kind (extended) modular version of  MSY2 MIDI-to-SYNC Converter that Doepfer sells? ( A-190-X maybe? )

If i might suggest some extra features, why not add a 16 (or more) trigger outputs (A-160/A161-style) , SYNC-in possibility, reset output(s) and switches on the front for choosing dividing factors.

That, together with a set of MIDI In and Thru, or an internal link possibility  to the A-190, would make an awesome (and not too expensive) module that for example could be used for percussive effects like triggering drumsounds in Sync with your old equipment.

Gate vs Trigger

Both the terms Gate and Trigger are commonly used for a signal out event type, mostly generated by a keyboard or sequencer, to start the process of generating a note or sound.

A trigger is typically of short (fixed) duration, where a Gate is usually continuous and muted when a key is lifted.

Gate-times can often be altered, in fact an Envelope Generator is not much more than a trigger-to-gate converter, often with different kinds of variables.
Most commonly used types of EG's are from the ADSR type ( adjustable Attack, Decay, Sustain and Release time ), but you can also find simpler AR, AD or ADR modules in other analogue systems.

Volts per Octave

The Volts-per-Octave standard luckily turned out to be a quite good one.
A lot of (early) synthesizers manufacturers adapted this standard, 'invented' and popularized by Bob Moog.

Best known manufacturers of early products using the 1V/Oct standard are Roland, Moog, Sequential Circuits, Oberheim and ARP. The big benefit of standards like these is inter-compatibility between products of different manufacturers. It allowes them to communicate better.

The V/Oct standard was wider adapted as other standards, like for example Yamaha and Korg's Hertz-per-Volt standard, that  represented an octave of pitch by doubling the voltage. 
A few synths that use the Hz/V standard are:
Korg: 770, 900-PS Preset, M-500 Micro Preset, M-500SP Micro Preset, Mini Korg, MS-10, MS-20, MS-50, Synthe-Bass, X-911
Yamaha: CS5, CS10, CS15, CS15D, CS20M, CS30
Moog: Taurus I Bass Pedals
Paia: 2720, 4700 Series

The Hz/V standard was used before the log converter was used in VCO's and is essentially linear control as can be found on various signal generators and function generators like those used by the BBC Radiophonic Workshop before they got a VCS3*. There are/were solutions available that convert from  Hz/Volt to V/Oct and vice-versa.  ( like the Korg MS-02 ).

No wonder that the A-100 system uses the V/Oct. standard. You can easily synchronize your system with almost any (old) machine that you have lying around, and most MIDI-to-CV converters use the same standard too.

For example i love using the CV (and Gate) output of my Roland TB-303 to control my A-100 system. The signal arrives at my system via a  A-180 2x4 multiple, so i have 3 copies of both signals available at any time.
Sometimes i use the CV slightly detuned for an interesting effect, sometimes i put it through a voltage inverter first, something that doesn't work out with all your 303-lines because of tuning.

The Gate output (trigger) of the TB-303 can be sent through a delay for some more interesting echo-like effects.
There are so many possibilities for your other gear to communicate with your A-100 with the 1 V/Oct standard... just go ahead and try... and amaze yourself.

*thanks to Tony Steventon for additional info

A-164-1 Manual Gate

I love hands-on control over my Doepfer A-100 Sytem:
I simply love my Ribbon Controller, the Joystick, Wheels and Theremin Modules, and this one is also one of my favorites.

Perfect for manual ( one-shot ) triggers is the A-164-1 Manual Gate Module.

This module has 3 seperate trigger-buttons that generate a 12V voltage at their respective Gate outputs when pushed. On release no voltage is sent.

All 3 Buttons have double outputs for even more flexability and functionality, and Gate/Button 1 can also be controlled by an external signal ( e.g. the rectangle output of an LFO ),  what makes button 1 act like a momentary on/off switch. This can add some nice ( rhythmic ) effect to your patch.

I prefer to use this module as a manual trigger for self-made one-shot sounds like cowbell sounds or other weird electronic (drum-) sounds. ( Pjoewwww)
In these patches i mainly use the buttons to trigger one or more ASDR's or envelope generators

Another interesting application for this module is extreme filtering...
Because the output of each  Gate is 12 V, feeding this voltage into a CV input of a filter ( or it's resonance control ) will lead to an abrubt ( and full! ) opening and closing of the filter at the push of a button.

As with almost all A-100 Modules, possibillities are limitless.
Leave a comment if you have more interesting and/or creative use for this module.