Dieter Doepfer – Creator Of The A-100 Modular System

Munich in July 2013. Gorgeous sunshine, a picture-book sky, a perfect day to be doing things outside. Despite swimming weather, 50 enthusiastic modular freaks have made a pilgrimage to Dieter Doepfer’s A-100 workshop for 3 hours of fascinating insights into the modular world. We asked Dieter Doepfer – not only highly qualified, but also an entertaining speaker – to give us an interview.


GS: It is commonly said that there is a successful woman behind every successful man. Do you agree?

Dieter Doepfer: Definitely. The company wouldn’t have gotten anywhere without Sibille (Heller). She’s the all-important connection between the product and our customers. I could develop fantastic instruments behind closed doors. But what good would that be if they couldn’t be sold? I do have to somehow make a living (o:

GS: You two have just come back from the world-famous Jazz Festival in Montreux (Switzerland). Kraftwerk had invited you to their concert. What was your impression?

Dieter Doepfer: Being a dyed-in-the-wool Kraftwerk fan, I’m prejudiced, of course. That goes back to the days before they were even our customers. The concert was fantastic, although I must admit some of the performances were maybe a little too long.


It’s not really necessary to refurbish old songs for modern taste, although I must admit the concept of live performance is moving more and more in the direction of the rehearsed show (think of those 3D-concerts). Aside from a few acoustic details (more “wumms” in the percussions, multiple channels, etc.) the music remains essentially unchanged. Which is fine with me.

GS: Do you have close connections with that German cult band? Would you say that Kraftwerk has influenced the development and concept of some of your products?

Dieter Doepfer: Sure. For instance, recently there was an R2M (Midi Ribbon Controller) on the stage. And in the near future a Dark Energy might be the only analog sound source at some performances. We recently built a new navigation system for the roboter, so that the movements can be controlled by the sequencer. The work on new concepts and products was mainly done with Florian Schneider, who is of course no longer part of the group. The sequencer MAQ 16/3 – our money maker – was developed in close cooperation with him and we also had his advice for the vocoder modules of the A-100 system.


GS: Now you can reap the harvest of many years of hard work. Which your new car, for example, makes obvious … (o:

Dieter Doepfer: Ok, ok … but after 20 years it’s perfectly obvious that your old car could have rusted out from under you …!

GS: Let’s talk about those beginnings. You too, like Bob Moog, are not a musician in the purest sense. You’re actually a physicist. So how has music become the center of your world?

Dieter Doepfer:  Look, as with many people, when I was young, I needed money. So during my physics studies, I earned my money making music (at weddings and parties, like everybody else).


But it soon became obvious that the technical aspects behind those instruments fascinated me more than the music itself. I started repairing amplifiers, speakers, mixing consoles, etc. for my friends. And somehow I got word of the so-called “synthesizers” that were being made in the USA. And those were being used by ELP, for example. I got all the information I could about them (remember – there was no internet at that time) and also about the other synthesizers, like the Formant modular system. I actually built one of those myself.

It was a real piece of luck that I got a service contract for the Moog Modular System from Gershon Kingsley (“Popcorn”). The system was in a hotel in Munich at that time and we bragged quite a lot about our skills (“… no problem, we can do it!”). That service manual subdued us a lot and we spent a lot of hours learning all the stuff we had bragged about already knowing …


GS: Your name had already appeared in music publications of the 80ies. The articles those days were all about new sampling technologies and your own first modular systems. But still: these days, it would seem that your break-through came very, very late, that it took very long to reach your present level of prominence. Can you fill us in on the company‘s success story?

Dieter Doepfer: It all started out at a leisurely pace. Having graduated and done my military service (civil service), it was time for me to face the question of what I was going to do in the future. Further research? Involvement in industry? An independet career? I decided on the latter, although those years were anything else but easy and I had to depend on my family for support. Although it had always been said that what I did could not be lucrative, in the meantime I have proved that to be definitely wrong. The secret is to be patient and to stay stubborn. My first independet project (the PMS = polyphonic Modulsystem) was not exactly a success, but somehow you have to earn a name for yourself at the beginning.

The fact that the Curtis company (producer of those well known synthesizer chips) entrusted me with European sales, was another streak of luck. I scratched all my savings together to pay for the first order. I developed the so-called VMS (Voice-Modular-System) on the basis of the Curtis ICs. And here, finally, the sales figures were such that I could make a living. I dabbled a little in sampling technology. At that time, the Sound-Sampler was part of the VMS and you could simulate various types of synth techniques (Fourier, FM, Waveshaping, etc.) using the Commodore C64. Admittedly, the sounds couldn’t be adjusted in real-time. The parameters had to be calculated from scratch.


Then things got very quiet around analog synths. Everybody wanted digital sounds.

I started developing MIDI master keyboards together with Christian Assall. To be honest, we really first became known on the market with the master keyboard, although that’s not my world. That’s stuff we developed to make money, and not because of any ideology.

Then, in the 90ies, there was a turn for the better and analog synths were suddenly “in” again. It all started with the MS-404 in 1994. That box exceeded all our expectations – we really had trouble keeping up with the demand.

Since the MS-404 was selling well, I tried to arouse the interest of musicians with an affordable modular system. The first A-100 modules were nothing more than circuits from the MS-404. Here I was really into my own. Although a lot of people around didn’t think there was a demand for it. But I stuck to my guns and didn’t change my mind. (These days there are probably more than 50 companies selling A-100 compatible modules and there must be more than 800 of the modules themselves). In the first years of production we brought out a new module every one or two months. I was able to benefit from the knowledge I had gathered in the 80ies in circuits. I just had to transform the designs into an up-to-date modular system.


GS: The A-100 Modular System has developed enormously in the past few years. How many different modules have been developed up to date? And, assuming you want to tell us, what’s the total of all the A-100 modules that have been produced? 100,000 …?

Dieter Doepfer: We have developed approx. 120 different modules up to now. But we’re also open for cooperative work: the A-171-2 VC Slew Limiter that recently appeared is a licenced copy of a Serge Module. The total number of A-100 modules sold up to now far exceeds 100,000 (but less than a million!). But that’s all I’m prepared to say (o:

GS: Does production take place in Germany?

Dieter Doepfer: The development, final control and final adjustment continue to be done at our main office in Munich. We have several producers in Germany and wider Europe who assemble and pre-test the modules. In case you’re hinting at the Far East: we don’t produce in China. We produce exclusively in Europe.


GS: What are your favourite A-100 modules? Why?

Dieter Doepfer: There are a couple that come to mind. The BBD Module (bucket brigade device, A-188-1/2) is one of my favourites. Then there’s the Wave-Multiplier (A-137-1) and the Sampler (A-112), and all the modules that have to do with sequencing (A-155, A-154 and – soon to come – the A-157 Sub System). Those make it possible to produce sounds not available with “classical” modules. The A-137-1 is almost an inverted filter, that is, you can add overtones to a very slender signal (sine/triangle). And the BBD Modules give you unimaginable, crazy sounds if you keep the clockrate low (outside the BBD-specifications).

Regarding the Sampler Module – I don’t use the sampler to play plain samples, but only in wavetable mode, in which case I don’t use wavetables but samples (language, for instance) instead. You can “surf” through the “wavetable” (a word or a sentence that you feed into the sampler) by a CV-source (an LFO, an envelope, …) and a second CV source allows you to change the pitch. Sonic results are very exciting …!


GS: Dieter, you’re a real pioneer. Not only because you have built many special modules, that can only be found with the A-100 system, but also because through you the 3HE modular rack has become a worldwide standard. It’s not without cause that we speak of the “Doepfer Eurorack Format”. What advantages do you see in that particular size? Do you also see weaknesses or disadvantages in the Eurorack Format?

Dieter Doepfer: The 3HE-Format I used for the front plates and frames was an industrial standard in those days. I came across it all the time when I was working on my physics thesis. I used the format with the early VMS (Voice-Modular-System) and re-activated it with the A-100 modular. But although the frame remained the same, I changed the interior concept. In the A-100, I replaced those ridiculously expensive bus boards and inflexible circuit board sizes used by the industry (Euro-Format 100x160mm) with a less expensive and more flexible bus/circuit board system. That allows the circuit board size to vary from module to module. You don’t have to use (and pay for) full-size circuit boards all the time, just when you really need them.


I see no real disadvantegs in the Eurorack Format. But for those wishing more generous placement of the knobs and switches, the Eurorack system may not be suitable. I personally prefer smaller knobs (those Cwejman modules are really nice!). But that’s all a matter of taste. A Moog Cascade Filter in Eurorack Format doesn’t sound any different than in another, larger format.

GS: Alongside the A-100 Modular, you tend to wander off into the land of standalone-synthesizers every couple of years. Take the MS-404, the Dark Energy I and – now – the Dark Energy II. Do you have any more big plans in this direction? Can we expect a Doepfer Synthesizer with integrated keyboard (a keyboard in the true sense of the word) in the near future? Synth Project has made some pretty remarkable suggestions. We’re thinking of the „Doepfer DIY-Synthone“ …

Dieter Doepfer: Naturally, we have thought along these lines. The big problem is which keyboard to use. Beyond the 88-weighted-keys fraction the musician’s world is very divided as to which keyboard is ideal.


We did a survey once, before we built the A-100CGK CV/Gate keyboard. (A keyboard, by the way, that is no longer in production due to lack of demand). 25% of those asked opted for the 4-octave keyboard size. The other 75% was divided. Preferences ranged from 2 to 6 octaves with various other options (weighted, not weighted, different key forms, normal or inverted key colour, …).

That list perfectly explains the problem. Many customers say: “use a simple keyboard and people will be happy with what they get.” But our experience has been that they can get any keyboard they want from Fatar and everybody has his own preferences. Which just isn’t realistic when we’re talking about production. That, in effect, was the problem with the A-100CGK CV/Gate keyboard. Everybody wanted his own keyboard. Ralf Hütter wanted (and got) an organ keyboard with 61 keys and pressure point simulation for live performances.


GS: Let’s go back to your means of conveyance (your automobile (o:) … We take it that a little luxury is something you can afford now and then. Down to the letter, you could be going into retirement soon. Is retirement an option for you? Can you imagine NOT developing and building instruments?

Dieter Doepfer: I cannot deny that we’re finally carrying in the harvest after 30 years of hard work. But my main means of conveyance is still my bike! It takes me to the company every day. Rain and winter (spikes!) don’t daunt us at all. On some weekends, we do 100 kilometers and more. And we’re not talking about a racing bike, we’re talking about a trecking bike, which takes me through fields and along wayward country roads. My car is definitely not a status symbol. It has to spend most of its time in the garage, and really only comes into its own during longer trips (to Montreux, to Kraftwerk, for example).

Analog synthesis is still my great passion. Why should I do something I enjoy less (mowing the lawn, pulling weeds, reading “good” books)? So I’m definitely not going into retirement. The only thing I can imagine doing is a little more travelling. But then I can always take along my laptop with Pspice (simulation programme) and Eagle (circuit board layout programme) in case things get boring.


GS: Well, we from the synthesizer world hope you will stay around for a long time! Thanks for the interview …

Dieter Doepfer: My pleasure!

Filed under 2013, Interviews

“Es genügt, einen Ton schön zu spielen” sagte der Komponist Arvo Pärt im Jahre 2005. Diese Aussage ist ebenso einfach wie ich auch exzellent: Es braucht kein Meer an Tönen, denn entscheidend ist der Klang. Dass so mancher Vintage-Synthesizer der 70er und 80er Jahre teils unerreicht hochwertige Klänge liefert, steht außer Frage. Doch tatsächlich leben wir “heute” in einer nahezu perfekten Zeit. Einerseits hat man – mehr oder weniger – noch Zugriff auf die Vintage Analogen, andererseits wird auch bei Neugeräten die wichtige Komponente des hochwertigen Klanges wieder zunehmend berücksichtigt. Doepfer, Cwejman,, MacBeth, Moog, GRP, Studio Electronics, COTK, John Bowen und andere Hersteller bauen hervorragende Synthesizer, die den “Klassikern” in nichts nachstehen. All diesen (alten wie neuen) “großartigen” Instrumenten ist Great Synthesizers gewidmet. _________________________________________________________ In 2005 composer Arvo Pärt said: “Playing one tone really well is enough”. In other words, it is sufficient to play one tone 'beautifully'. I agree with that. All musical efforts are focused on the sound itself. Although I studied classical music (piano and drums), it’s the electronic sound that inspires me. Synthesizers are the epitome of new sounds and exciting tonal spheres. Today, many companies produce high-quality - excellent! - synthesizers: Doepfer, Cwejman, MacBeth, Moog, GRP,, COTK, Studio Electronics, John Bowen and others. It's their products I'm really interested in ... apart from Vintage Synthesizers, which I have been collecting for 20 years. Subsequent to our former websites Bluesynths and Blogasys, Peter Mahr and I have now created GreatSynthesizers. We hope you like it.


  1. Great interview. Really good to here Dieter’s story from his own perspective. What’s with all the references to his new car though? You might at least tell us what he’s driving!

  2. Theo Bloderer

    … it’s a brand-new (and very beautiful) Audi Coupe … (o:

  3. Thomas

    Many thanks to you and Dieter for this very exciting interview.

  4. I have an MS-404 which I love. it is funny to see how the keyboard size & type seems to block Dieter from rolling out more ready to play machines. Arturia did not bother and had an absolute hit. The thing is, nobody will ever be 100% with whatever kb you put up. You could argue that modular allows for anyone to be happy since it is 100% open. But conversely, some people may not want to be that open ! Also, with 120 units or “skis” I wonder how the economics work in terms of 80/20 split in sales efficiency. But that’s another point. In the meantime, kudos for this man, his vision and passion. And business.

  5. Theo Bloderer

    … your comparison with Arturia is interesting. The French success shows that a Dark Energy with keyboard (maybe a double-engine synth with true stereo features) or a Dark Energy / Dark Time couple with integrated patchfield and keyboard probably would have been a hit as well …

  6. The problem with keyboards and Dieter may also be thinking this, is why spoil the well developed, trusted and good name with bad press? People will bitch and moan if it’s not got 5octave or something else, the brute was fine for what it was, a 3 octave is perfect if mono or duophonic IMO. Would be nice to see Doepfer go poly or even a 3osc mono, a powerful mono with good sequencer even, they have all the tech so my last thought is perhaps they as a business can make more from modules so adding the keys and a whole enclosure is not so inviting?

  7. And could still be, with a slightly revised dark energy engine mmm mmm

  8. Vik Vandecaveye

    I dream of something like a studiologic sledge, but with a doepfer engine in it… No digital waldorf.

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