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Showing posts from 2010

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…

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.

CD-Tip III : Analogklang - Modulsystem A-100 Demo CD

This CD was published by Doepfer in 1995 to show off their then brand new A-100 modular system. It has 29 tracks and a large, colorful, fold-out booklet (in German) with a description of most of their early modules.

All the basic modules are demonstrated on this CD, that was produced by Andreas Merz from Weltklang and  narrated in German by a vocoded voice. The tracks are short, between 25 seconds and 3½ minute, what brings the total length of the CD to just 30 minutes.
This CD itself must be a collector's item by now i guess, because the item isn't available anymore on Doepfer's website. I'm quite sure i won't sell my copy... ever. This CD still means something special to me, and i did listen a lot to it, even before i bought my first modules.

Although the CD isn't available anymore, all tracks ( and some other sound-examples ) are still available for download HERE ( ...sadly enough in a poor ( 16Kbps) quality due to file-size decisions, but if you really nee…

Modifications III : A-127 Triple Resonance Filter Expander (part 2)

Hmmm... that went faster as i expected.
My brand new self-made A-127 Expander Module is now almost finished.
( Find part 1 HERE)
The switches are wired too, and the overall look of the module is even better as expected.

I did have some trouble with drilling holes through the aluminium front-plate at first, but it seems i aligned the sockets nice enough with the output sockets of the A-127 itself.
The switches work smoothly and the 'new' 12 dB filters sound sweeeeeet.

I'm very happy with this module, and glad that i went with this option instead of just putting switches on the A-127's front panel.

The wiring of the modules on the backside was quite simple. Red wires were used for switching between the different filter-modes, the blue ones the the audio-multipliers, and yellow ones (not visible in the picture) for the lower switch.
I did the soldering without removing anything from the module, but you might want to remove some components for easier access.

Instead of sol…

Modifications II : A-127 Triple Resonance Filter Expander

Now that i finished my first 'real' module-modification i couldn't wait to start with the next project.
At first i wanted to replace a red LED for a blue one on one of my modules myself, but i couldn't decide which module i should pick for this... and i'm still not sure, but that can wait....

Another plan that was in my head from the beginning was the placing of 3 switches on the front-plate of my A-127 Triple Resonance Filter. There are 3 jumpers inside this module that allow the user to switch the filter-type of each of the three channels between Band-Pass (standard) and 12 dB Low-Pass. I have seen some examples on the web of this modification, most of them just with the switches mounted on the A-127 itself, but unexperienced as i am, i was too afraid to damage the front-panel and went for an Expander Module design.

So that is why i am building it into an official 4HP blind-panel that i bought from Doepfer. Each of the three A-127 channels on my expander module …

Modifications I : A-156 Quantizer Follow

Yesterday i picked up the spare parts that i ordered from Doepfer; a few switches, 3.5 mm sockets, LEDs and blindplates of different types and sizes. Now that i have them i couldn't wait to start with my first project.

One of my personal little annoyances that i have with the A-100 system are the tiny internal jumpers inside of some modules. Behind these jumpers are sometimes great functions that make these modules a lot more flexible.
Where i can, i will try to replace the internal jumpers with switches on the front on more modules, but i started with the A-156 Dual Quantizer Module.
This module has two separate Quantizers, one that only uses a semitone-scale and Quantizer 2 that has much more options like minor/major/chord/quint/6th and 7th scales. There is a way to let Quantizer 1 follow Quantizer number 2 by replacing an internal jumper, but why there? It is probably a cost-saving thing from Doepfer's side but there is enough room on the frontplate of the module to place …

PatchPierre Mobile Template (beta)

Good news for visitors on Android, iPhone and other mobile devices. As of now the site is visible in the mobile template, with quicker loading times and easier browsing through the posts.
The site now automatically  changes into the new template when you visit it, but you can also get there by scanning the QR code or following this URL:

Nokia / Symbian users can still download the
PatchPierre Mobile App HERE ( 3500+ downloads already )

UPDATE December 25th 2010:
Thanks to the OVI-store, people on Android,iPhone or other mobile devices can also use the OVI-Template of the PatchPierre site... it even looks better than Blogspot's own template.
Try it out and point your browser to
( Don't forget to bookmark it! ) 

SiteTip II : Doepfer A-100 series modifications by Nick Keller.

Another nice site i stumbled upon in the last weeks in my search of Doepfer DIY info is the Doepfer A-100 series modifications site byNick Keller at

This site offers some great (and easy-looking) Doepfer-modifications, complete with step by step explanations and pictures. Most of the modifications are simple but very usefull and consist of adding more switches, inputs and outputs to the frontpanel. Very interesting stuff... I'm looking forward to try some of the examples and hope that the parts i ordered from Doepfer will arrive soon, so i can start experimenting on my first Doepfer-projects.

The mods described will most likely void any warranty and, if not done carefully, can damage the circuit board, IC chips, and faceplates.

Quotes III : Robert Moog

" I'm an engineer. 
I see myself as a toolmaker and the musicians are my customers... They use my tools."

Robert (Bob) Moog

DIY Projects I : The Beginning

I bought my first prototyping board (or breadboard) and some jumper-wires last week, it's time for me to start learning about electronics and electonic circuits.

The board i got was of the Velleman brand, and to be sure i had enough room on it i bought one of the bigger boards, still for under 20 Euro's.
I also bought a small Velleman Voice Changer Kit (MK171 - 9,95 Euro) , the only audio-related DIY-project i could find to experiment with. Like i said earlier this stuff is quite new to me, and my first attempt will be the mounting of all the parts of the kit onto the breadboard. This seems like a good practice for me to learn more about the components and their functions.

I did learn a lot on YouTube last weeks about the basics of breadboarding and electonic components, and there are a few good (and free) tutorials on the MIT OpenCourseware site ( both video's from lecture 12 are highly interesting and deal with basic sound creation with electonics ) The 559 pages thick le…

A-114 Dual Ring Modulator

A Ring Modulator is a signal-processor that produces a signal out of two different audio inputs.
This output signal is the sum and the difference from both inputs, and leaves the original frequencies out.

It is an ideal module for producing metallic or bell-like sounds, but you can also (re-)create other weird sound-effects with it, like for example the distinctive "Daleks"-voices from the classic Dr. Who series, created in 1963 by the BBC Radiophonic Workshop. Besides voices, you can also input all kinds of other (amplified) instruments through the ring-modulator.

The Doepfer A-114 Dual Ring Modulator is in fact two ring-modulators in one, which makes it even more flexible. Theoretically you can use the output of the first ring-modulator as input for the second one. The A-114's manual has some nice other examples on how to start patching, but with a bit of imagination you will quickly come up with your own ideas.

You can find some more interesting ring-modulation (DIY) in…

PatchPierre Mobile App for Symbian Update

Version 3 of the PatchPierre Mobile App is now available in the OVI-store.
The ultimate way to watch PatchPierre's content on your Nokia device. It works on all Symbian and selected S40-devices.

The app enables easy browsing through the PatchPierre posts and comments and also links to the original articles.
Added in Version 3 are the PatchPierre Twitterfeed and my YouTube Videosection with jams, demos and other music made my me. Find it on the web at

The app will stay free in 2010, the 1 Euro that it will cost in 2011 will be spent on upgrading my A-100 system and maintaining the blog. 

All other donations are welcome too, there is a PayPal donation button in the blogs' right column.

ClickHEREfor a direct link to the OVI Store

More screenshots after the break:

50th PatchPierre Post


Funny how time flies....It's time for a small celebration.
The reason is because this is my 50th PatchPierre post.
What started out as a personal  hobbyblog has turned out to be quite an impressive collection of interesting posts... (if i may say so myself...)
When i started it, in March of this year, i never expected it to go this fast, and i am still impressed by the number of readers and the variety of countries where they come from.

I would also like to take the opportunity in this post to thank a few people here for their inspirational and motivational support throughout the process of shaping this blog;
In the first place i would like to thank Marc Weerts ( @MarcJX8P ) from the band 87PM ( ) for the idea of the subtitle of the blog (Connected Chaos), and for his valuable feedback in all these months.
I would also like to thank Loek van der Helm ( @wonderhelm ), mainly for his technical (PatchPierre-app)-support.
Last but not least i would li…

Booktip IV - The Complete Simmons Drum Book by Bob Henrit

Perhaps a bit of an outsider on this blog, but this 104-page book about Simmons Electronic Drums is in fact quite an interesting read.
The British Simmons company produced drum modules since the late seventies and is perhaps best known for their distinctive sounds and their 'hexapad' drum-surface design.

This book tells the whole story, their conception, development, and even their problems.
Allmost all their drumkits are included in this book, from their first SDS-3 (SDS series), ClapTraps and expanders up to models that were never released.
The book was written and published in 1987, seven years before Simmons produced their last products so only a few models are not mentioned in this book ( like the TurtleTrap and the SDS-2000 )

I have no idea why this book was written, but it looks like a nice thick brochure to sell Simmons products.
It is filled with (b/w) pictures, background stories and stories by players and is very well-written.
I recommend this if you are interested…

Most Wanted II - Drum Modules

Drum-synthesizers and drum-machines have been around for a long time.
The first analogue drum synthesizers were introduced in the 1970s, and everyone remembers those classic analog and digital rhythm-boxes made by big companies as Roland, Korg, Simmons and Linn.

 The Mid-nineties analogue revival triggered a whole bunch of new manufacturers like MAM, Vermona and MFB (to name a few) to produce (modular) drum synths.
I always wondered why Doepfer hasn't come up with a modular drum series yet.
The only drumsound-providing module they released so far was the A-117 Digital noise/808 Source, a module that only produces two 808 sounds... ehh well... building blocks.

Wouldn't it be nice if you could fit a variation of different Doepfer drummodules in your rack, perhaps an A-117-X series? How about dedicated Basdrum, Snare, Hihats, Cymbal, Clap and Toms modules etcetera, with (dynamic) triggers and CV-controllable functions like decay, tune, attack and so on, so you could use any CV sign…

PatchPierre.Net is live

Another small but important step in PatchPierre history;

www.PatchPierre.Net is claimed and live now... easier to remember if you are 'on the go' and want to check out the latest posts.

Service provided by in Sassenheim / The Netherlands.

SimpLL Solution offers IT-products and -services for businesses

Blind Panels

The regular Doepfer 19-inch Euro-rack system has a usable width of 84 HP. If the modules you install don’t use up the entire 84 HP, you are advised to cover up the empty spaces with blanking panels due to safety and EMC reasons.

As i wrote in an earlier blogpost, the (static) electricity from the system causes the A-100 to be a real dust-magnet.
Blind Panels are available in the following sizes;

A-100B1  : 1   HP
A-100B2  : 2   HP
A-100B4  : 4   HP
A-100B8  : 8   HP
A-100B42: 42 HP
A-100B84: 84 HP

Doepfer also sells the A-100B1.5, a 1.5 HP wide blind panel that for example fits the  Analogue Solutions modules together with eurorack modules of other manufacturers.

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…

SiteTip I : Tone's Analog Synthesizer Projects and Products

I stumbled upon this interesting site last week; Tone's Analog Synthesizer Projects and Products. You can find it at
The overall site looks like a good start for everyone who is busy with, or starting on eurorack synthesizer DIY-ing and is operated by Tony Steventon, a UK electronics design engineer with a long interest in synths.
"Like most ideas it came out of trying to solve problems..." he wrote to me "... I could not fit either the jack sockets or bracketed pots on to standard 0.1" perfboard and came up with this idea over a year ago".

He continues "...several people have expressed an interest in learning how to take an idea through to a design and onto a prototyped module which I am quite tempted to do as a future 'learning' page on my blog..." "...I am working on my CV Tools module at the moment, which I have prototyped using my kits, but when that is ready for manufacture I am happy to consider …

Filters I : A-127 Triple Voltage Controlled Resonance Filter

It is hard to say what my favorite A-100 filter is. Every filter has its own distinctive sound, and they all have a lot of Control Voltage input possibilities. I must admit i prefer low-pass filters... and filters with many outputs.

The A-127 VC Triple Resonance Filter is 3 bandpass-filters in one, each with its own LFO (sine) with adjustable frequency. The module has 3 individually adjustable outputs plus a mix output, and with all the controls for filter frequency and resonance it is a very flexible module.
\All 3 filters have an external CV input too, that by-passes the LFO when a plug is inserted in the socket. The amount of incoming CV's can be attenuated with a knob.

I love the sound of it, one of the characteristics of the 12 dB/Octave filters is that it can produce almost vowel-like sounds.
The LFO's can create amazing filter-sweeps as well with the frequency-rate adjuster.
As modulation inputs various CV's can be used like ADSR's and other LFO's (triangle/saw/…

Busboard Access

Updated August 25th 2011

A good patch can sometimes turn out to a whole spaghetti of patchcables.
Luckily Doepfer provided the A-100 system with a subsystem that makes the routing of some Gate and CV signals through the internal busboard-system possible.

It's too bad that not all modules have this ability, but for some modules this is a good way to avoid "over-wiring" your system with patch-cables.

Only modules A-110 (Standard VCO), A-111 (High end VCO), A-111-5 (Mini Synth. Voice), A-140 (ADSR), A-164-1 (Manual Gate), A-185-1 (Bus Access), A-185-2 (Precision Adder) and A-190-1,2,3 and 4 (Midi Interfaces) have access to the CV or Gate signal of the A-100 busboard.

The A-164-1, A-185 (-1 and 2) and A-190 (-1,2 and 3) can be used to "write" the busboard, i.e. they can output the signals to the bus.

The others are able to "read" the busboard, i.e. they pick up the signals CV (A-110, A-111, A111-5) resp. Gate (A-140, A-164-1) from the bus.
The A-111-5 can …

Quotes II : Tom Rhea

" Sound is sound. There is no such thing as an 'artificial' sound - only sound or silence.
A synthesized sound is not a replacement for a 'real' sound; all sounds are real "

Dr. Tom Rhea - Electronic music historian

Happy Knobbing III - New Joystick-Lever

The latest minor modification to my A-100 system  is the replacement of the A-174 Module's joystick.

I finally changed my black plastic lever with a newer aluminium one that i ordered at Doepfer last week.

Modules before 2007 had the black plastic lever as standard, all modules delivered after 2007 already have this aluminium lever.

It's just a small optical change, nothing more. The new lever is a bit shorter, but does have a nice/better grip though. And that for only 10 Euro's...

<  Old vs. new lever

A-134-2 Dual Voltage Controlled Crossfader

My latest ( my 60th! ) Module is the A-134-2 Dual Voltage Controlled Crossfader.

This module, that contains two identical voltage controlled crossfader units can be used in combination with controller modules like the Wheels or the Joystick controller to make fades between different sounds  ( or even control signals like LFO's ) 
Each unit has two voltage controlled amplifiers (VCAs) with opposite control behaviour. In standard (assymetrical) mode, with 0 volts CV added to CV1, input A is fully closed and input B fully opened. Adding more control voltage to the CV1 input will result a volume increase at input A and a decrease of the volume at input B. In the middle position you will hear a nice mix of the two inputs.
Different settings for the module are available, by switching the internal jumpers you can make the CV inputs ready for bi-directional voltages ( positive and negative ). By coupling both units you can even control 4 inputs with, for example the A-174 Joystick Module's…

Booktip III - Synthesizers by Hans de Vries ( in Dutch Language )

This little Dutch book, written in 1983 (!) is probably one of the best synthesizer-technology-books that I own. The fact that it is written in Dutch wasn’t enough reason to keep this book out of this blog.

In 144 pages, Hans de Vries explores the basics of sound creation.
The first half clearly explains the basic building blocks of synthesized sound, very clearly written (... but in Dutch, remember...) and with lots of graphs and explanatory pictures ( b/w )

The second half of the book delves more into the use of synthesizers in practical situations like (home-) studio’s etc.. The book ends with an overview the most popular or groundbreaking (analog) instuments of that time, like the Korg MS20, various Moogs, Oberheims and Rolands, up to the fisrt digital synthesizer; the Yamaha DX-7

Funny detail in this book is the writer’s skepticism towards MIDI and Computerized sequencing. Remember... around 1983 there were only a few instruments equipped with MIDI, and computers weren’t cheap. A…

Oscillator Synchronizing

Interesting sound-effects can be obtained by the synchronising of (multiple) oscillators.
In a typical setup, one oscillator (master) restarts the cycle-period of the other one (slave) , what results in equal base frequencies on both oscillators. This is called Hard Sync.

The result is an irregular waveform with it's own harmonic spectrum, completely different from 'standard' waveforms

Soft Sync is a more general name for all kinds of oscillator synchronisation.
This form is very similar to Hard Sync, but here the slave oscillator is forced to reset to zero with every cycle of the master regardless of position or direction of the slave waveform, which often generates asymmetrical shapes.

In Soft Sync, rather than resetting to zero, the wave is inverted;  its direction is reversed.
Further variations to the sound can be made by comparing the sounds with different comparison tresholds. For more info see the Wikipedia page on Oscillator Synchronisation
Soft Sync sounds smoother …

Quick Tip III : Vocoder testing

Ideal for ( Doepfer ) vocoder testing;

Try feeding an audio-book or a recording of your favorite radioshow through your system while tweaking your vocoder settings.

Speech-only programmes are perfect for this purpose.

Short demo:
In the Morning Vocoder test by NetPierre
* original audioclip from: /

Quotes I : Edgar Varèse

"I dream of instruments obedient to my thought and which with their contribution of a whole new world of unsuspected sounds, will lend themselves to the exigencies of my inner rhythm."

Edgard Varèse


A filter is a device for eliminating selected frequencies from the soundspectrum, and in some cases to emphasize the level of other frequencies.

Lowpass filter: Removes frequencies above its cutoff frequency

Highpass filter: Removes frequencies below its cutoff frequency

Bandpass filter: Only allows frequencies to pass through above and below a specified range

Notch filter: Allows frequencies to pass between specified ranges ( = Band-Reject filter )

CD-Tip II : Popular Electronics by Philips Research Lab

This 4-CD Boxset with the subtitle  " Early Dutch Electronic Music from Philips Research Laboratories 1956 - 1963 " is a collection of great (restored) works from the Dutch pioneers in electronic sound.

These four CD's contain hard-to-find compositions and sound-examples from the groundbreaking Philips NatLab studios in Eindhoven, the Netherlands.
Pioneers from that time like Dick Raaijmakers,Henk Badings and Tom Disseveld were already working on electronic sounds in the late 1950's, and this collection of Dutch electronic and tapeloop-music is the most complete one ever compiled.

The boxset includes 7 booklets (180 pages) and a few mini-posters, full with background information on the history of Philips NatLab and the composers and technicians of that time. You will also find all the CD details in these books, as well as lots of pictures, scores, schematics and other related documents.

Popular Electronics: Early Dutch electronic music from Philips Research Laborator…

A Question of Cables

Doepfer sells  patch-cables for the A-100 system (3.5 mm plug mono jack) in many different colors and sizes.
The latest addition to the Doepfer assortiment are the orange 50 centimeter patchcables with angled plug on one side. 

The prices are fairly acceptable, and the more you buy ( at once ) the cheaper they get each...
Sizes vary from 15 (yellow), 30 (black) , 50 (grey), 80 (red) , 120 (blue) to 200 (green) centimetres, but i wish they also had other lengths. (...and colors)

Let me know in the comments if you know a place where they sell patch-cables in other colors or lenghts, it will be appreciated.
Purple ones would be nice... but not too long... ;-)

Never Enough VCO's

The engines or hearts of all modular synthesizers are definetely the VCO's. As main sound source for your patches it seems you never have enough of them.
I own 5 VCO's at the moment, One A-111 High End VCO plus four A-110 Standard VCO's. Ideal for stacking layers of waveforms to make extra- fat sounds, and also very useable for multiple A-100 melodylines
The A-111 is the one i use most because of its extended possibilities.  This VCO has an extended frequency range, improved waveforms, FM and Soft Sync inputs plus an extra fine-tune-controller. Ideal for controllerfreaks like me.  It produces sine, triangle, pulse and sawtooth waveforms, which are all derived from the triangle oscillator, what does make it hard to produce perfect sine-waves ( but a little better as the A-110's sine wave ) One of the best things is that all 4 waveforms are all simultanously available at the outputs for your mixing pleasure.
The much cheaper A-110  has less controls and is based on a sawtooth …

A-100 Module Circuit Board (Picture)

Most of the Doepfer A-100 modules' circuit boards are really pretty. It is almost a shame to build them into a case...

They almost look like a well-architected mini-city on a tiny Doepfer-board, almost like LEGO- miniature-city.

Patchpierre MiniQuiz:    What A-100 Module is this?*

* Answer is HERE - feel free to take the short Poll; "  Analogue or Analog?  "

Analog Noise vs. Digital Noise

My Doepfer A-100 system includes 2 Noise different generators, the A-118 Noise/Random Voltage Generator, and the A-117 Digital Noise Generator.
A noise generator is an oscillator that produces an internal noise signal, typically white or pink noise. Noise Generators produce random signals, containing harmonics on all frequencies, and can be modified into the desired tone. 
The A-118 produces white and colored noise. The white noise is the well-known 'hiss'. The spectrum for the white noise has the same amount of energy in every section.  The colored noise output of the module is a mix of blue noise ( high frequency component ) and red noise ( low frequency component )
Noise in the audio spectrum can be used in many ways, most commonly in wind-effects, or in cymbal crashes and hi-hat -sounds.
The A-117 Digital Noise sounds very different and has less control possibillities. This module has 2 outputs, consisting of mixes of multiple oscillators to re-create vintage Roland TR-808 and…