Forty years with synth DIY

Everything started with the Elektor magazine

My interest in synthesizers started in 1972, when I heard the songs Popcorn by Hot Butter and Son of my Father by Giorgio Moroder. I was only a child and could not buy records but I had managed to save money for a cassette recorder. So it was a matter of taping songs from radio. One of the favourites was Rod Hunter's synth cover on the Shadows' Apache.
In 1974 Kraftwerk released their album Autobahn. I had saved money and bought a stereo set and this became my first synth record.

Fast forward to 1976. A class mate at the upper secondary school loaned me Switched-on Bach by Wendy Carlos, which I taped and loved. Promptly I bought her LP with the music to the film A clockwork orange.
One day in the autumn of 1977 I discovered the British magazine Elektor at school. They had the issues where the Formant article series started. There I found out, to my amazement, that you could actually build your own synthesizer!
Since I had chosen the technology program at the upper secondary school and was aiming for the electrical engineering program in the third year, I really wanted to get started with something electronic and this seemed like a dream come true. However, electronics wasn't on the school program until a year later. This didn't stop me and I learned the necessary electronics from the very excellent magazine articles before I got it taught in class.

A design study I made for the planned synth. I have always been interested in industrial design. My synth wasn't going to use the standard Formant front panels.

Since I had no equipment to etch circuit boards, I made the first boards by grinding off the copper from blank copper clad fibreglass boards.

The board looks like this on the component side. This is my version of the Formant VCO. It actually worked. Eventually...

The front panel even looked rather nice, with rub-on lettering.

The module case with the modules I had built. My choice of 19 inch rack panels fore the modules turned out to be less than ideal.

After the module case, I built a keyboard unit according to this drawing. The keybed was from Wersi. Unfortunately, I have no decent photos of this unit.

Another picture of the module unit. I never finished more Formant-based modules than these.

For the fourth and final year, I had to switch school. The new school was located at Södermalm, the part of Stockholm where most of the music instrument stores were. On the lunch breaks me and some classmates used to go to the stores and admire the synths. I specially remember the Yamaha CS80, which had some amazing features and was incredibly expensive.

I felt the maths had become too abstract in the final years of school. On an information day at the Royal Institute of Technology, they informed us that most of what you studied there was maths, maths and maths. I didn't apply. Instead I got a job as a service engineer at Siemens mainframe computers when school finished. It was quite easy to get a decent job in 1980, even as a certified upper secondary school engineer!

First thing on my first job, I was sent off to Munich, Germany for a two week introductory course. That was tough, since everything was in German and I was the only one on the course who was not from Germany. I had studied German in school but I had never been to Germany before.

Back home in Sweden, things went OK at the job. In late 1980 we were seriously short of service personnel and Siemens decided to loan us an engineer named Hans Kolber from Munich for a couple of weeks. While I was driving him to a customer's site, he asked me if I had any articles or plans for the 8085 microprocessor. He was interested in using it for a hobby project.
I said ”No, I haven't looked at microprocessors. I'm more interested in synths”.
He said ”Really?” (or rather, something equivalent in German).
It turned out he was into synths too! He even had brought a Synthi AKS, which he used in the evenings when not working. A couple of evenings later I joined him at the flat Siemens rented for loaned-in personnel and was introduced to the Synthi.

A couple of months later I was in Munich for another course and met up with Hans in the Siemens service department where he worked. He suggested we should go to Merianstrasse where he knew a person named Dieter, who made and sold synthesizer kits. This sounded interesting to me, so I was happy to agree.
Arrived at the flat, we were greeted by Dieter and first admired an early Moog modular which he had in for service. Then we had a demo of his kit system. It was a polyphonic modular synth. He also had an interesting phaser unit, which I believe was his very first kit. I left there with a couple of his kits, the printed instructions for a few more and a number of D-mark notes missing in the purse.

Circuit boards to Doepfer's polyphonic modular system

The polyphonic modular system could be built with four or eight voices.

The voice assignment in the polyphonic keyboard was a bit primitive, as it didn't use a microprocessor.

Of course, the new polyphonic modules did not fit into my keyboard unit. To make more room, I designed a new bottom, which added height (the black part).

The visit to Munich had also made me a member of the Informationskreis Musikelektronik. They had formed the year before and produced a photocopied publication with synth and electronic music articles six times a year. Back when there was no Internet, this was the one of very few ways to get hold of such information.

This is what we had when there was no Internet.

I learned to photo-etch circuit boards at home and started work on a polyphonic synth based on the Doepfer boards and some of my own ideas. But such a system of course meant a lot of work and progress was slow. No doubt also because other interests took a sizeable part of my time.

It turned out, the enlarged keyboard unit was still not large enough for the polyphonic system. Among other things, I needed more panel space. I had to design and build a new one.

This is how the new keyboard unit looked when built.

New ideas evolved faster than I could build. This became more and more frustrating. No matter how much I worked, the synth didn't get closer to completion. Most of the work was in replacing things I had already built but which I wasn't satisfied with.
At around 1985, commercial synths started to come down in price and I now had a decent income. Also, the commercial synths had new features that my DIY system lacked. With the possibilities midi promised, I finally gave up and bought an Ensoniq Mirage instead. An Atari ST computer with Steinberg Pro24 sequencer gave me possibilities my DIY synth could never have had. Soon, however, I missed the analog synth sound. This problem was solved the year after, with an Oberheim Matrix 6R, which I still have and love. My polyphonic DIY system, using the Doepfer boards, never reached playable condition.

Time went by and analog synths became retro cool. In 1998 I got the idea to refresh and repackage some of the modules from my Formant period into a traditional but more compact modular format. With the Doepfer Polymodule quad VCO board, I would have plenty of VCOs for a monophonic synth.

I first tried a 2HE format for the new modules but this didn't turn out quite well. Here is the Formant 24 dB/oct VCF with a new front panel.

The Doepfer Polymodule quad VCO could just as well be used for a four VCO monophonic synth.

I now had access to Internet at work and somehow found out about the Synth DIY mailing list. Somewhere I was able to download the original schematics for most of the Moog modular modules and this inspired me to try and build some of them. I also came in contact with the Swedish SAS mailing list and through it the schematics for the ASM-1 synth. The Bergfotron was born. I decided on an own standard with 3HE modules. At that time there was no dominating standard on the market, like with Eurorack today.

The first case for the Bergfotron was 19 inch rack sized and had room for two rows of modules. Note the handles. They were carried over from the old Formant case. This small case was soon outgrown.

After some time I was allowed some web space at work and then the Bergfotron website became reality.

In the middle of 2000 I had built more modules than there was room for in the case. A new, larger case was needed. Inspired by the ARP 2600, I decided to have built-in speakers. To simplify things, I choose to integrate PC-speakers from Creative, complete with subwoofer. This turned out to be a bad choice, since it made the synth extremely heavy. I made the decision to tear out the speakers. This, however, made the case a little unnecessary large.

The new, much larger case. Note the speaker grille on the side.

Eventually I got internet access at home and a small server space with it. In September 8 2002 the Bergfotron site opened on my own server space and has been available there ever since.

The Complex VCO was one of the last modules I built for the original Bergfotron. It was inspired by the Buchla Programmable complex waveform generator model 259. As you can see from the side view, it was indeed a complex module.

I was getting tired of all the mechanical work involved in making modules. Especially that you had to make considerable mechanics work before you even could test the module and decide if it was worthwhile, sonically. Also, I wasn't quite satisfied with the modular approach. It's tedious and time consuming to create patches, which in my case meant that not much music was created with the synth.
I wanted a system where the boards could be thoroughly tested before committing to the mechanical work. I also wanted general purpose circuit boards that could be used in a classic modular but also in any other type of synth. Even a polyphonic one.
After a lot of thinking, I had a concept that fulfilled my wishes in the spring of 2008. The AMORE standard was born.

The first AMORE board, the dual voltage controlled bandpass filter.

In the last ten years, my activity in the synth hobby sector have varied greatly. There has been many more AMORE boards released but there has also been long periods of no activity. What will come next remains to be seen. The move to marks the forty year anniversary for my synth DIY hobby.