A-100 Knobs Change

Special announcement from Dieter Doepfer, in the Doepfer Yahoo Usergroup:
Updated Feb. 13, 2012, see below...

" I just wanted inform you that the knob manufacturer (ReAn Sulzer / Switzerland) has stopped the production of the knobs that were used in the A-100, MAQ16/3 and other products. 

We tried to buy the productions tools from ReAn as they are no longer used. But ReAn was not willing to sell the moulds.

We are about to find another manufacturer who is able to produce a copy of the knob but I'm not sure if the copies will look exactly the same. 

I assume that all modules manufactured until end of this year will still be equipped with the original ReAn version of the knobs. 

But from early in 2012 the modules will be delivered little by little with the new knobs. 

We will try to get new knobs that look as close as possible to the old ones but I'm not sure if there may be a small noticeable difference...

...Sorry - but we will try to continue with the A-100 as it is (same knobs,same panels). It's all a matter of taste. 

And if we change to other knobs I'm quite sure that many other customers would complain. 

If someone wants other knobs he may replace the knobs as the 6 mm 18 theeth shaft is a standard. 

From my point of view continuity is important for a product like the A-100 system. 

I would probably change some things if I could put the wheel of history into reverse (but not the knobs, the panels and the printing as I still like them). "

Best wishes
Dieter Doepfer

Update Feb 13, 2012:
" There is still some "fine adjustment" to do (exactly the same "grey", exactly the same width of the marker and so on). 

At first sight the samples of the new knobs look identically but if you compare an old and a new knob next to each other you see some minor differences (grey color and line width). 

But I'm confident that the manufacturer will be able to change these small details."

Booktip X - Onder Stroom by Jacqueline Oskamp (in Dutch Language)

It took me a while to get through this book, but here is finally my long promised book review.
"Onder Stroom" ( the book is in Dutch, "Under Current" might be a fitting English translation ) by Jacqueline Oskamp is a book that tells the history of early Dutch electronic music.
You have probably seen my earlier blogposts on this topic too, if you didn't, HERE's a link.

With 6 portraits of the groundbreaking and/or pioneering Dutch composers like Ton Bruynèl, Dick Raaijmakers, Jan Boerman, Michel Waisvisz and others you get an amazing insight on how the Dutch electronic pioneers worked and struggled with electronics, audio, speakers and tapes in a very conservative post-war musical era.

Each in their own way, they were driven by their curiosity, found new ways of sound-creation and explored the spectrum between noise and sound.
Their influence lead to a pretty diverse electronic music scene in the Netherlands; from the pure electronic and almost mathematical approach to the pure tape-music, along with live electronics with orchestras and electro-acoustic setups you could say these early 1950s and 60s were 'our' golden years ( i'm Dutch too).
And that all started for us only half a century ago (!) If you just look around and see what has changed in recording and sounddesign.
I know we were a bit behind on the rest of the world or Europe; Leon Theremin, Edgar Varèse and Karlheinz Stockhausen, to name just a few great minds, already paved the way and had also inspired some of our pioneers.

This book is very interesting if you're into this kind of stuff, but also very pleasant to read if you have little or no knowledge of electronics and the techniques at all.
Very impressive is the list at the end with read- and listen-tips, and the book has a section of  8 pages with b/w pictures of the composers, sadly not many pictures of the equipment...

- An interview (VPRO Vrije geluiden / in Dutch) about this book with the writer can be found HERE
/ interview starts after 19 minutes - with music by Dutch artist TokTek
- Read more on the worldwide history of electronic music on Wikipedia HERE

Published in 2011 by Ambo/Anthos
Paperback 251 pages.
Info ( in Dutch ) HERE          ISBN: 9789026323249

Bla-Bla Blue LEDs

And again, i have been too busy lately with replacing some red LEDs by blue ones. I believe this was my final batch, but you'll never know...

As i mentioned before on this blog i like those blue LEDs a lot, but some modules weren't available with blue LEDs at the time i bought them.
I'm not considering making my whole A-100 system with blue LEDs, that would be too much, but just a few blue lights make my machine just look sooo cool. (in the dark)

This kind of work also helps me to practice my soldering-skills.
I'm (still) not the best in it, but i am slowly improving... and i do these replacements in less time.

I do not pick my LED-replacements completely at random. Most of my new blue LEDs have a  'deeper' meaning; better see it as a kind of color-coding.
Some of these LEDs need special attention, others sometimes act (slightly) different than the red LEDs next to them, and if there is no direct reason to change a red LED into blue i'll always tend to find one...

Take a look at the new overload LED of my A-126 Voltage Controlled Frequency Shifter ( that is no longer available ) for example. This little LED just screamed for attention every time i used this module.
Earlier i replaced the overload LED of the A-119 External Input, so it seemed logic to replace this one too.

The other LED that i replaced was one of the A-147 Voltage Controlled LFO.
I'm not sure why exactly, but three blinking red lights in a row... Who needs that?
I replaced the middle one, the one that displays the output of the rectangle wave.
It is the only one that does not gradually fade out and in like the other two, it is either on or off, at a CV controlled variable speed...

...I told you I'd find a reason... ;-)

A-147 VCLFO with 1 blue LED

More on replacing LEDs HERE

Filters IV : A-103 18 dB Low Pass TB-303 Filter VCF6

The A-103 18 dB Low Pass filter (VCF6) is Doepfer's own 'TB-303 filter clone' ;
It uses a so-called transistor ladder with a slope of 18 dB/Octave as frequency controlling element.

It is very similar to the transistor ladder of the A-120 24dB Moog type Low Pass filter, but the ladder of the A-103 is a modification of the original Moog ladder and identical to the ladder used in the Roland TB-303.

The in -and outputs are very basic; Three CV inputs are available, and the sum of the voltages from these affects the filter cut-off.
And an audio in- and output are also available, with one level knob.

That is the same layout as the A-102 and the A120 so sadly there is no CV control over the resonance. 

Luckily the resonance cán be adjusted with a knob, all the way up to self-oscillation.

And how does it sound?

I've always loved the sound of a real Roland TB-303 and the sound of it's filter.

This one sounds very nice too, it has that nice warmth in the lows, and the typical sharp edge when resonating, but don't expect that you can re-create a whole TB-303 with just this single module.

Some of the TB-303's other features, like the glide, accent and envelope modulation are missing here, and they (partly) give the legendary acid machine it's very original character.With some creative patching you should get very close to re-creating that original Acid sound...

I got pretty close by using my MAQ 16/3 for the sequence, and the A-160/A-161 Clock Divider/Sequencer combo for additional 'accents'. (You can add an LFO, or Noise for more random accents to experiment with / ,an  A-142 VC Decay/Gate envelope is also a useful addition with CV modulation to CV2 of the A-103 to create basslines like that* )
Overall this filter module can be a nice addition to your Eurorack. (7/10)

Video: Doepfer A-100 does TB303


* thanks to Jakob Paulussen  (@Jakobsweb) for that last tip and the kind permission to embed his video here. More info on the video after the break:

CD-Tip V : Anthology of Dutch Electronic Tape Music Vol 1 and 2 - Various Artists

These summer weeks i have been too busy to blog regularly, but i did have time to read and listen.
The main topic of this summer's research was Early Dutch Electronic (Tape) Music, you can expect the review of the book "Onder Stroom" (in Dutch) by Jacqueline Oskamp later, but first this quick quadruple CD-Tip.

This 2 x 2CD collection gives another nice overview of the early Dutch Electronic and Tape-pioneers.
It shows the listeners that there were more creative people interested in the spectrum between noise and sound besides the people who worked at the Philips NatLab (more info HERE and Wiki HERE).
A collection of work from throughout the Netherlands from Dutch legends like Dick Raaijmakers, Henk Badings, Ton Bruynèl, Tom Dissevelt and more from the years 1955 to 1966 fills up Volume 1.
Volume 2 has music from the years 1966 to 1977 and contains compositions of lesser known tape-artists that were not included on the first volume.

"Anthology of Dutch Electronic Tape Music Volume 1 Electronic music has been the subject of intense activity in the Netherlands since 1955, and the variety of this activity is reflected in the histories of the large number of electronic studios. The aim of Anthology I is to illustrate both the work of the various studios and that of individual composers; we have tried to represent as many composers from each studio as possible with preferably their earliest and most characteristic works...

... The second and last volume of the Anthology of Electronic Tape Music contains works composed after 1966, during a period when electronic music broadened its horizons and established links with other disciplines, a period when the studios opened their portals to influences and involvement from outside. Although electronic music from 1966 onwards became very fragmented and manifested itself in many different forms in Holland, the present volume of the Anthology aims merely to give an overall picture of pure tape music. "

Overall i find this a perfect compilation series. Most of the compositions sound fresh ( also because of the brilliant remastering by Kees Tazelaar) and at times make you feel excited and amazed on how this could be made half a decade ago without 'modern' effect machines.
If you are new to Dutch Electronic Tape-Music and you need a good starting point, try these 4 CD's.
Together with the 2 thick inlay-booklets (in English), that provide info on each track and a short composer biography this is a very complete and diverse overview...

Published in 2008 by Basta Music
http://bastamusic.com
Volume 1 2CD: Cat. Nr.: 3091 822 / More info HERE
Volume 2 2CD: Cat. Nr.: 3091 832 / More info HERE

More Blue LEDs

Okay... I haven't had much time to write and post these last weeks because i'm too busy working this summer, but i'm not completely sitting still.

The new blue LEDs that I ordered arrived, so the next few weeks i will only be replacing some red LEDs by blue ones.
It's not the most exiting modification, but it will make my A-100 system more pretty IMHO.
( Info on replacing LEDs HERE )

I do have time to read during my work, and i'm reading a very interesting (Dutch) book called "Onder Stroom" by Jacqueline Oskamp at the moment.
This book tells the story about the history of electronic music in the Netherlands, so expect a book-review of that in the near future.
( The book is slightly related / overlapping  THIS )

I will be back with some more interesting posts in a few weeks... so please stay tuned!

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 )

Quotes X : Bernie Worrell

" I talk by playing, not by words..."

Bernie Worrell  Musician, Keyboardist, Composer, Producer, best known as a founding member of Parliament-Funkadelic

Doepfer Usergroup Poll: Analog Shift Register

Another new Poll at the  Doepfer A100 Modular System Users Group is up.
This time it is about the idea of realizing a Doepfer Analog Shift Register A-100 module.

A few days ago this was posted:
" ...It has been a while again, so I'll bring it up again. I believe it is time for a Doepfer analogue shift register... Does anyone agree with me?... " (*edited)

To be honest, i had never heard of an Analog (or digital) Shift Register, but a quick search on the web provided some hugely interesting information.
For the basic theory on what a Shift Register does i'd advice you to read the Wikipedia page first.

Shift register working principle  (Source)

For the musical use and a brief history on Analog Shift Register modules there is an excellent post at http://hardsync.blogspot.com, describing most of the known Shift Register modules.

" Ok, so what is an ASR? An ASR module is a sophisticated S&H. It will, at every clock pulse, sample the CV value of the input and makes it available at the first output. So far, it's a basic S&H. The thing is, a ASR has many outputs, and what it does is that at every clock pulse, it shifts the value of output 1 to output 2, and likewise, value of output 2 gets to output 3. So at every clock pulse, the CV values gets' shifted to the next output with the exception of output 1 that samples a new value at every clock. " *

Doepfer does call it's own multifunctional A-152 a "Voltage Addressed Track&Hold / Analog Shift Register (ASR)/ Octal Switch (Multiplexer) ",
but Hardsync writes " I own a Doepfer A-152, and my opinion is that the claimed ASR function of the A-152 will not get you the true ASR results you might expect. The A-152 is a switch. A very powerful and sophisticated one, but it will not push the value of one output into the next. Therefore, not a ASR as we defined."

Dieter Doepfer himself replied to the new poll very quickly;
" Though the A-152 is not a real ASR you can do similar things with this module. The most frequently mentioned application is to distribute a control voltage to the CV inputs of several VCOs.
At the rising edge of the clock signal of the incoming CV is sampled and routed to the next VCO. For this function an ASR is not essential as the VCOs are equivalent.
But there may be applications that require a "real" ASR (I'd be interested in applications where an ASR is required and that cannot be realized with the A-152).
In case that we will develop an ASR we'll go the digital way, i.e. ADC - processor - multiple DAC.
This has a lot of advantages, e.g. no voltage loss of the analog S&H capacitors, included quantizer for VCO pitch applications and some more.
But I'm not sure if the expected sales will justify the development of such a module (especially as we have already the A-152 available).

Update August 3 / Dieter continued;
" We already discussed the chance of multiple functions in the company.

One could treat the ASR as kind of a ring memory that could be "filled" in different ways. E.g. from a CV source via AD conversion (the usual ASR) but also via Midi or USB. The ring memory could be looped or not by means of a simple switch. 

One could combine the module with arpeggiator functions, e.g. fill the memory by playing a chord on a keyboard and then use only one of the CV outputs. 

One may also fill it with several analog CV's and the filling could be triggered by a gate signal (i.e. output of a sequencer or a CV/gate keyboard). That way one could combine several similar functions in one module. From my point of view this would make more sense than a pure ASR. 

One could combine the functions of an ASR, arpeggiator and and a rudimental digital sequencer. For ASR the number of steps could be limited e.g. to 3 or 4, for the arpeggiator and sequencer more steps make sense. A lot of ideas for the long evenings of the upcoming

fall and winter .... :-) "

Find the poll and vote HERE / Please join the Doepfer A100 Modular System Users Group by registering first.

The question in the poll is plain and simple;

Would you want and buy a Doepfer Analogue Shift Register module?

O - Yes!

O - Maybe...

O - No

* Source: http://hardsync.blogspot.com

SiteTip IV : Doepfer Convergence Group on Soundcloud

If you are interested what kinds of sounds other Doepfer users make, or just want to be inspired, you can always go to the Doepfer Convergence Group on Soundcloud.

This site contains very interesting creative compositions made mainly on a Doepfer A-100 Analog Modular System.

The group is moderated by James Bragg (AKA HyperDust), a synthesizer player and producer from Bristol UK who has played in various bands since the early 1980's and who's musical styles have varied over the years from New Romantic, Rock, Rock/Dance, Trance and various electronica.

" I've been building up 2 suitcases of modules over the last 5 years. I love their immediacy but also their temporary nature.
There is a type of Japanese painting where you paint with water on a special stone. It can look beautiful but after a short time it dries and is gone forever. A Doepfer modular is a bit like that. I'll never get that sound again - you just have to live in the moment. Celebrate the now. We spend too much time worrying about the future, and regretting aspects of the past."

The group has 49 members, and 18 tracks already have been contributed by 10 different musicians.
Some of these are complete songs but it also includes long live-improvisations and weird soundscapes.

Definitely worth a listen, if you have some spare time... Here's a quick preview, just to give you an impression;

 biofeedback no.9 by cubistic microsonic 

Quick Tip VI : Theremin Antenna

By accident i learned that the same kind of thing that i advised for the A-198 Ribbon Controller (to remove the USB-cable from the controller after use, read the post HERE ) counts for the A-178 Theremin Controller's antennas as well...

If you, like i, have your A-100 system placed upright , the weight of the antennas is just a little bit too much for the mini jack connector.
The permanent sideways pressure, caused by the weight of the antenna can cause loose contacts of the connector. If you have your module installed on a flat (tabletop-like) surface the plugged-in antenna cause less sideways pressure and you'll probably be safe.

Although Doepfer uses a new type of jack sockets since 2003 with stronger springs and so-called "curly rear contacts",  loose contacts can hardly be prevented.
But don't worry, if this problem occurs it is not a huge problem because most of the times you can fix them yourself by following the instructions that you can find HERE.

In my humble opinion it is just better to unplug your antenna from your A-178 module when you are not using the Theremin functions.
Better be safe than sorry...

Timing Capacitors of the A-100 System

Okay... I did write a little about the Timing Capacitors of the A-100 modules in my latest post, but i found it so interesting that i thought i should do another short post about this.

Timing Capacitors of the A-118

If you want to modify a module yourself please read this document first: Timing capacitors of A-100 modules.
That document is intended for experienced A-100 users who want to modify the timing range of some modules (e.g. envelope generators, LFOs, slew limiters). 

To lengten the time or period the capacitor value has to be increased and vice versa. The capacitor value is proportional to the time or period (e.g. doubling the capacitor value even doubles the time or period, when the capacitor value is increased tenfold even the time or period increases tenfold). 

By request the time range of delay and/or length can be modified very easily by changing the value of a capacitor, e.g. 200 us...1 s or 20 us ... 100 ms or 2us ... 10ms. That way the module can be used also for audio applications.
If an electrolytic capacitor is used one has to pay attention to the polarity (minus and/or plus sign).

Timing Capacitors of the A-119

Although Doepfer has very clear pictures on their site on where to find the right capacitors i decided to make a library of my own as pictures with info for your comfort.
Here are two already, expect more in the coming next months.

Feel free to use and/or distribute... More promotion for the site is very much appreciated ;-)

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

A-162 Dual Trigger Delay

The A-162 Dual Trigger Delay contains two separate delay circuits for trigger signals.
This module makes it possible to delay the onset of trigger pulses.
This is very useful in case you want the modulation to kick in a little after the initial start of a sound (modulation delay) or to create interesting echo-like effects.

Both trigger delays have two controls that can alter the onset time and duration of triggers, standard from 0 up to about ten seconds.
The time range of delay and/or length can be modified very easily by changing the value of a capacitor, e.g. 200 us...1 s or 20 us ... 100 ms or 2us ... 10ms.
That way the module can be used also for audio applications.

If you want to modify the module yourself please read this document: Timing capacitors of A-100 modules.

Locating the A-162 timing Capacitors C2 and C5

Timing capacitors:
C2 (delay time)
C5 (length)
Standard value: 10uF
Polarity: minus = left

Also check out THIS post from navs.modular.blog on how to modify a Doepfer A-162 Dual Trigger Delay for perfect filter pings.

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

Doepfer Usergroup Poll: MS-02 Module?

A new Poll at the  official Doepfer Usergroep is about the idea of realizing an A-100 module with the possibillities of the 'classic' Korg MS-02 expander module.
This module was part of Korg's MS series of instruments, which also included the MS-20 Monophonic Synthesizer, the single oscillator MS-10, the keyboardless MS-50 module, and the SQ-10 sequencer. Additional devices included the MS-01 Foot Controller, MS-03 Signal Processor, MS-04 Modulation Pedal and VC-10 Vocoder.

( MS-02 user manual with detailed info online available HERE )

" In my search for a Korg MS-02 I haven't been successful so far. In building a great A-100 modular synth I was. This got me thinking: It would be great if Doepfer would add a module to the A-100 module list with the functionality of the Korg MS-02. I can imagine more people are interested. I sent the question to Dieter and he suggested to start a poll on this list. So here we go. "

Options:
O - I would be interested in a Korg MS-02 like module as long it's cheaper than 100 euro
O - I would be interested in a Korg MS-02 like module as long it's cheaper than 150 euro
O - I would be interested in a Korg MS-02 like module as long it's cheaper than 200 euro
O - I'm not interested in such a module

To vote, you can go to the Yahoo! Groups Poll HERE.

More info controlling a MS-20 / MS-10 with a Doepfer device HERE

Most Wanted V - A-100TKB Touch Sensor Keyboard

Perhaps best known for their non-moving touch sensor keyboards were the Electric Dream Plant Wasp and Gnat ( and the Electronic Music Studios EMS Synthi A * ) synthesizers that were produced during the late seventies/ the early eighties.
Doepfer's Touch Sensor Keyboard was announced a loooong time ago.

There have been many prototypes of this , and there have been many suggestions and discussions, but still there is no final design or release-date in sight.

Prototype #1

The first prototype (2005?) was a sequencer + keyboard all-in-one version, that looked like the original Sherman Filterbank, but with a keyboard with metal plates in front of it.
For their second prototype (2007), Doepfer decided to drop the sequencer, to give the buyers the chance to buy their own sequencer ( if they needed one ). This prototype is still my favorite, with it's 25 metal keys... simple and plain.

Prototype #2

In the first two versions of the TKB the hum noise inducted by the sourrounding mains was used as working principle, but they found that this principle did not work perfect in all cases (changing mains intensity, different mains frequencies 50/60Hz, indoor/outdoor, problems with increasing humidity and some problems more).

The Latest prototype, shown at NAMM 2010, was equipped with 16 uniform metal plates. Here is where Doepfer went for another approach, now with capacitive sensing pads.

Still, this was a prototype, and i bet Doepfer got a lot of feedback, but probably not enough (or maybe even too much) to make a final production-model.

From the Doepfer site: 

" The number, shape and dimensions of the pads can be adjusted to the customers wishes but we will be able to manufacture only one or maybe two versions (e.g. one with a keyboard layout like version 1 and 2 and another with a non-keyboard layout like version 3).

Prototype #3

In any case it is planned to separate the control until (i.e. the potentiometers, sockets, LEDs and so on) from the touch section. The touch section could be like a module (i.e. assembled like a module to the frame) or a separate box with a cable that leads to the control module (or external control box for stand-alone applications).

As an option we think about a pressure sensor below the keys that measures the pressure applied to the metal plates. The touch keyboard will be probably equipped with outputs for Gate, CV1 (pitch), CV2 (pressure) and Midi.
Due to the nature of the keyboard velocity measurement is not possible and even the Midi output is monophonic only.
Suitable supports to mount the keyboard case into a 19" rack at different positions and angles are planned for the touch version of the keyboard (not possible for the normal version as the width is more than 19"). We also think about a DIY version of the TKB, i.e. only an electronics without the metal plates that can be used to connect any metal plates that have to be added by the user. "

More detailed info on the whole TKB project HERE

* Thanks Marc

Booktip IX - Analog Synthesis by Reinhart Schmitz

One of the smallest books in my whole BookTip section, but nevertheless a pretty informative one is this 128-page booklet by Reinhard Schmitz.

Analog Synthesis -The Newbie Guide to Synthesizers and Sound-Design  (also available in German) is full of basic info on how synthesis works. Very easy to read, and focused mainly on beginners this is a nice resource for all things synth...

In different chapters the main components of a (modular) synthesizer are explained, accompanied by simple  black/white pictures and graphs. 

The book is completed with an extensive glossary and a pretty nice 39-track audio-CD with audio-examples of the most important analog synthesizers of Moog, Oberheim, ARP and Sequential Circuits, to name but a few.

Some time ago Doepfer used to give this book (or the German version) away for free if you purchased a full Doepfer system. 

Getting it is better than buying it; for such a small book the price ( 36 USD ) is a bit too high IMHO...

Wizoo has quite an extensive collection of other English and German audio/ recording -books too.

You can find the other English books here

ISBN:  978-3-934903-01-2
Publication Date: 1999 by Wizoo Publishing GmbH

More info on this book HERE

Discontinued A-100 Modules

Good things come and good things go...
There are many different reasons for manufacturers to stop producing certain modules.
Sadly for some people, some components of a few Doepfer modules aren't available anymore.
Some of the special circuits ( or IC's) in the modules have become scarce, or not available at all ( like the original knobs ) , and that has been a reason for Doepfer to discontinue the production of some of these modules.

Another reason to stop producing certain modules is because they just don't or didn't sell... maybe just because they are not very useful (anymore) or they disappeared when newer modules appeared with (almost) the same function(s).

Soon a collector's item?

An overview ( updated February 2012 ) :

A-111 High End VCO  As the special circuit CEM3340 used in this module is no longer available the module has to be discontinued.
/ Sale while stocks last.

A-121 Multimode Filter As the special circuit CEM3320 used in this module is no longer available the module has to be discontinued soon.
/ Sale while stocks last (only 20 left in Januari 2012)
Doepfer recommends the A-106-6 XP VCF, that is based on the filter circuit of the Oberheim Xpander, as a replacement module.

...the A-101-9 Universal Vactrol Controller is the latest addition to the running out/ sale while stock lasts list... more info on this later

The A-111-5 Mini Synth Voice (and the Dark Energy) will also be discontinued because of CEM3394 chip running out... Stock is still available.
More info on this HERE

The following Doepfer modules are not available anymore:

A-123 24dB High Pass was discontinued at the time by poor sales, and the special circuit CEM3320 used in this module is no longer available.

...and another one...

A-126 Frequency Shifter Because the special circuit CEM3382 used in the internal quadrature VCO of the A-126 is no longer available Doepfer had stop the production of this module too.
But they are about to plan a succeeding model ( A-126-2 ) without internal VCO. The advantage of this solution is that even frequencies below 50Hz are available for special beat effects based of frequency shifting at low frequencies.

A-138x Mix Expander - Because of the poor inquiries the production of this module had been stopped too.

A-139 Headphone Amplifier, a 2-channel headphone amplifier with 2 audio inputs (3.5 mm jack sockets) and level controls, common loudness/master level control, 2 headphone outputs (stereo 1/4" jack sockets) - no longer available

A-177 External Foot Controller is now replaced by the A-177-2, a more economical replacement with a little less control (without LEDs and without scale controls), but with almost the same functions.

A-179 Light Controlled Voltage Source is also no longer available as the special circuit CEM3320 used in this module is no longer available. That is why this module also had to be discontinued.

A-191 MIDI-to-CV Interface / Shepard Generator no longer available

A-197 Analog Meter no longer available ( i personally never really expected an analog meter to be very useful, and i guess i wasn't the only one )

A-197-2 Oscilloscope kit no longer available -
I am still looking for an affordable oscilloscope though. I was thinking about something like a MFB VD-01 Videoscope, but sadly there's no budget at the moment...

Latest update: A-188-1Y BBD Module (256 stages) is also on sale while stocks last


Curious what chip is inside your synthesizer?
Check http://synthtech.com/cems.html and
http://sequencer.de/synth/index.php/Chips_in_Synthesizers

Modifying the A-124 Wasp Filter for self-oscillation

Out of the box the A-124 Wasp filter can not go into self oscillation, in contrast to most of the other filters in the A-100 system.
Lucky for us modifying the module for self-oscillation is quite easy;
Doepfer's DIY page tells us that;

"Soldering a 10k resistor in parallel to R13 (27k) leads to self-oscillation of the filter at the max. resonance setting of the resonance control."

Locating the R13 resistor was perhaps the most difficult part of the job. Because the resistors are all soldered on the PCB very tightly it is hard to read what the printing on the board says about the mounted resistors... but i found it!

Locating the R13 resistor

R13 is located in the gap between IC1 (CD4069) and IC2 (i.e. the upper CA3080, close to C4/100pF). See picture above.

I did have a few spare parts lying around, including a 10k resistor. Soldering in parallel in this case was very simple. I did this on the backside of the PCB.

After locating the correct resistor you can simply solder the new resistor on the other side of it. Not much can go wrong.

Just be aware that your soldering-iron doesn't overheat or burn your resistor.

I read mixed reviews of this modification, but you have to remind yourself that the A-124 itself acts kinda unpredictable in the first place, due to the design that "abuses" digital inverters as analog operational amplifiers leading to distortions and other "dirty" effects.

A post-modification audio demo by Madrayken ( Dene Carter ) can be found HERE

 WaspPostMod by Madrayken 

A-175 Dual Voltage Inverter

The A-175 (Dual) Voltage Inverter simply does what the name says; it contains 2 separate inverters that invert the voltage of incoming signals; an input of +4 V will be output as -4 V, an input of -3 V will be output as +3 V, and so on.

Two LEDs give a visual indication of the (positive or negative) output signal for each inverter.

I use this module a lot, as i blogged before, most of the time both inverters are constantly attached to my A-174-1 Joystick module. I am thinking of buying another one soon, because this module is just so useful.

I love the fact that each inverter has 2 inputs, so they can be used as a (mini) multiplier.
In this way you don't have to 'lose' the original signal.

As input source you can use almost any CV source, not just the ones that produce both positive and negative voltages. 

A simple LFO will do, and the Joystick and Modulation Wheels are also very handy basic controllers.

The A-175 manual has some interesting user-examples, including a basic panning patch and a scale/arpeggio-mirroring patch, but again; possibilities are endless, the only limit is your imagination.

Quotes IX : Jean-Michel Jarre

" I think that you have to seriously have fun, or taking serious things in a light way... and obviously for me before all, music is made of fun and pleasure and excitement. "

Jean-Michel Jarre  Composer, musician, artist, producer

(from WikiQuotes)

How To Hide an Arpeggiator

An arpeggiator is a feature available on some synthesizers that automatically steps through a sequence of notes based on an input chord, thus creating an arpeggio.

One of my biggest personal complaints about the 'original' A-190 MIDI-CV Interface was the fact that the front-plate had the text 'arpeg.' on it while an arpeggiator function wasn't even implemented (and still not) in this module.

Doepfer recently stated that "...there were plans to add an arpeggiator when the module was designed about 15 years ago. But we found that the processor power is not sufficient to add this feature..."
He also stated that the new A-190-3 USB/Midi-to-CV module does have an arpeggiator available. ( the A-190-3 is the modular version of the Dark Link and Dark Energy USB/Midi interface, watch an 8-minute video about the Dark Energy's arpeggiator functions below ).

The same functions should work on the A-190-3 ( and Dark Link ) too, but i haven't had any hands-on time with this module to check and haven't seen much info on the web.
It does look like a very basic arpeggiator that will be hard to program, only with external MIDI-controller-messages ( like the R2M if i am correct ), but it is a good start.
I would rather see a more dedicated arpeggiator module from Doepfer, with easy accessible buttons and switches for the different settings and run-modes. Something like the Toppobrillo Quantimator (PDF) or the forthcoming Flame Chord Machine would be nice...

The weird thing though is that the whole arpeggio function is not mentioned anywhere on the module's web-page while this is such a useful function.
In fact; it's the first A-100 module that has a (basic) arpeggiator (!)

Because an A-190-3 manual isn't available yet, you can find a bit more info on how the arpeggiator works in the Dark Link manual ( PDF /page 13)*

*thanks to Paul Rogalinski for the tip

Video: Using Doepfer Dark Energy Arpeggiator

Detailed reference video by Dmitry Shtatnov with Doepfer Dark Energy internal arpeggiator + live song performed using Dark Energy and A-100 modular system.

Black, The New Silver

Like it or not; It looks like Doepfer is slowly changing the main colors of their products into the new black and white color-scheme.
It all started with the Dark Energy synthesizer and the Dark Time sequencer, and recently they changed the case-colors of their USB/MIDI interfaces MSY2, MCV4 and Dark Link.

The first (and probably only) A-100-related new black thing is Doepfer's Ribbon Controller ( The R2M control box and the manual, not the A-198 module itself )
As of June 2011 the cases of this Ribbon Controller will be black with white printing instead of the old silver-grey look.

I like this move towards black from Doepfer because it does make these instruments and boxes look slick(er).
It is probably cheaper too for them to produce, but i'm not sure of that ( and doesn't really matter to me).

But what will be next..? Will they also change the A-100's front-plates?
I guess (and hope) not... that will seriously mess up the overall view in my opinion, although i do like the black and white look from the vintage Moog and Roland modulars.
Fact is that those modules are far better readable due to the high contrast, but i don't think they should apply this to the older A-100 modules. ( but íf Doepfer ever comes up with a range of specific drum-modules i wouldn't mind them being black and white because this can be seen as a separate (sub-) system... )

Filters III : A-124 Wasp Filter

The A-124 is a special 12dB multimode filter using the filter circuit of the EDP Wasp, a monophonic black and yellow analog synthesizer, that was built around the end of the seventies and manufactured by the UK company Electronic Dream Plant.

I totally love the sound of the A-124 Wasp Filter module. It does have it's own special sound due to the special circuits in it which makes the module sound a little dirty and distorted. This can sound very nice with extreme filtersweeps, i often control the cut-off frequency with the pressure CV from the A-198 Ribbon Controller.

The module has 2 audio outputs; a band-pass and a combined low/notch/high pass output that can be controlled with the 'mix' knob that defines the relative amounts of low and high pass signals.
( middle position is notch )

One downside of the module is the lack of a QCV input like most A-100 filters have, so sadly the Resonance cannot be controlled via an external voltage. You can only adjust this manually.
It would have been nice if the Mix could also be controlled by CV...   IMHO

Out of the box this filter can't go into self oscillation, in contrast to most of the other filters in the A-100 system, but modifying  for self-oscillation is quite easy;

Soldering a 10k resistor in parallel to R13 (27k) leads to self-oscillation of the filter at the max. resonance setting of the resonance control.*

 More info on this modification can be found HERE

100th PatchPierre Post

Woooooot! ...again. :-)

My 100th post already (the 50th was on December 7, 2010), and the blog is still going strong.
With fewer posts though, but the viewing rates are still slightly growing every month.
Thank you all again for regularly visiting this site and for your valuable feedback.
I hope my blog can still please the people who just got into analog (modular) synthesizers, and also provide the more advanced users with interesting links and different insights.

In this post i would like to take a quick look into the most popular of my first hundred posts.
Although i cannot exactly tell how many people read each post (many of the visitors land on the main page, where they might read multiple posts at once), i can tell by the individual clicks what the most popular posts were and tell a bit about their traffic sources.

By far the most popular post was my Busboard Access post from November 17, 2010.
I guess struggling for hours through the manuals for a complete overview of all modules that are capable to read or write to the A-100's busboard was worth it.

Also still very popular is my PatchPierre Mobile App for Symbian post from December 8, 2010.
I am still very proud with the almost 5000 installs of the application on Nokia Symbian and selected S40 devices. I do hope Nokia will find a way to port these kind of self-made apps to the Windows Mobile platform and Market too. The more installs, the better... :-)
I did get an email from OVI that my App will soon be updated with some new extra features and an 'enhanced user experience'. A blogpost about that will follow...  (meanwhile the app is still available HERE)

The A-101-2 Vactrol Low Pass Gate and  A-156 Quantizer Follow Modification posts were also quite popular, together with the various other DIY and Modifications posts that i did.
The Book-tips and the CD-tips also seem to be of your interest. I still have a few book-tips on the shelve, and i will try to post some interesting (synthesizer-related) CD-reviews in the near future too.

And... where did all this traffic come from?
Well, Google's search in all its varieties ( .com /.co.uk /.fr / .de / .nl ) was by far the #1 top referring site, but that is hardly a surprise.
Social Media-sites like Twitter (#2) and Facebook (#4) also proved to be very useful to attract readers to the site, and  a lot of viewers came from the Nokia/Symbian mobile application referrals ( #5, but not as much visits as i expected, a lot of people still seem to only read my blog in-app, thus still missing out on a lot of the links ).
More surprisingly was the #3 spot, because Tony Steventon's Synovatron.blogspot.com seems to have been a true link-farm for links to my blog. Thanks for that Tony ;-) Keep up the good work with your interesting projects!
The link to my site on the Doepfer A-127 webpage has also attracted quite a few (new) readers, i'm pretty proud with that one and it looks like the MuffWigglers have (re-)discovered/ finally found this blog too. ( thanks to THIS post ) I have seen a lot of traffic coming from there in the last month... Welcome!

I hope i can serve all of you with at least 100 more posts in the future, but it might take bit longer than the first 100...

Saving Patches

One of the downsides of a modular synthesizer is the lack of memory banks.
There are times when you have finally found that perfect sound, but need some modules for other patches...
A good (photographic) memory will often do the job in the more simple cases for anyone, but for bigger patches you might need a little reminder sometimes.

To 'store' patches you have a few options;
First, always try to sample the sound you made with a (hard- or software) sampler. Although that often does not catch every aspect of your sound, it is always good to keep what you made in some audio-way. Try sampling it in all its varieties, with your favorite settings and or knob-twists.

Okay... you now have the sound , but not the list of modules that were used to make that sound.
Doepfer came up with the nice idea of patch-sheets in the last page of every module's manual.
You can print out these modules, stick them on a bigger sheet (i've even seen some on pinboards) and draw in your knob-settings and patchcables.
The idea is/was nice, but i hardly ever used these sheets. But it can be handy for some...

I also like the online Eurorack Modular Synth Planner. With hundreds of modules from 52 different manufacturers (!) you will be able to configure your patch including a variety of colored patch-cables and save it as a screenshot.
This great site is regularly updated with the latest eurorack modules, but still has a few (small) bugs and imperfections. Follow them on Twitter to get their latest updates.
Another online planner is Stefan Breitenfeld's Modular Planner, also very neat but with much less manufacturers/modules.

My personal favorite way to store my favorite patches is the modern way.
Thanks to my smartphone i always have a digital camera in my pocket.
One or two quick snapshots of my patches is often enough, and only takes a few seconds.

LFO's A-145 and A-147

Low Frequency Oscillators or LFO's produce periodic control voltages that can be used as a modulation source for all kinds of other modules.

The A-145 LFO1 was the first and one the most basic single Low Frequency Oscillators that Doepfer sold.
It provides 5 different waveforms; sine,sawtooth, triangle, pulse and inverted sawtooth ,and each waveform has their individual (and simultaneous) output.
With the Frequency-knob and the 3-way switch you can select a wide range of frequencies, from on cycle every minute up to audio frequency at the highest.
A reset input allows you to synchronize the LFO signal to an external trigger signal and each trigger will re-start the waveform from its zero-point.

The most obvious use for an LFO is to do some pitch modulation on a VCO to create a vibrato and to modulate amplifiers (VCA's) for a tremolo effect, but with a creative mind you can use these two modules for all kinds of sound manipulating.

The A-147 Voltage Controlled LFO is basically the same LFO as the A-145.
It doesn't have one of the A-145's sawtooth waves, but does have an extra Control Voltage input that is very useful.
Think of an A-174-2 Wheels Module or A-174-1 Joystick Controller as the most used control voltages, but dare to think further... how about controlling the A-147 frequency with noise or perhaps another LFO for example?
My personal favorite use is to put a voltage of an A-198 Ribbon Controller or Theremin Voltage though the CV input and send it to an VCA to get a tremolo effect, but at a higher frequency in the higher notes.

I will discuss the A-146 LFO2 in a future post because it is a slightly different module with different features and uses.

Booktip VIII - History of House by Chris Kempster

History of House is a very interesting book about the history of House music and the technology behind it.
The book is compiled and edited by Chris Kempster in 1996,  the articles come from music-technology-magazines like 'the Mix', 'Music Technology' and  'Electronics and Music Maker' (E&MM)

The 206-paged book is divided into three parts; The Artists USA, The Artists UK & Europe and a third part that is called 'The Technology'

The first part contains interviews with some of the most influential house-deejays/producers like Marshall Jefferson, Lil'Louis, Larry Heard, Juan Atkins, Derrick May, Kevin Saunderson, Richie Hawtin and Carl Craig.
The interviews that the author/ compiler picked are very well written, and besides giving an insight into the history of house music, they also contain a lot of tech and synthesizer references. Most producers explain what instruments they used and why.
The second part of the book features UK and European artists Kraftwerk, M/A/R/R/S, S-Express, Baby Ford, 808 State, A Guy called Gerald, The Orb and Goldie.

The third and last part is all about the classic House-instruments and probably the most interesting for the readers of this blog.
Here you can find some  interesting articles about the classic house drum machines like the TR-808 and TR-909, the Roland TB-303 acid bassline, SH-101 and Juno 106 synthesizers, the Alesis MMT-8 and Korg SQD1 sequencers and from more modern machines like the Ensoniq Mirage, Yamaha DX100 to the Akai S-1000 and Kurzweil K2000 samplers.

Overall this is a very entertaining book for anyone who is interested in house music, the (mid-)80's synthesizer history and/or its instruments.  8/10

Sanctuary Publishing, Limited, 1996
ISBN: 1-86074-134-7