DIY Synths

A mki x DIY analogue synthesizer system. Ten kits are needed to make this, including two envelope generators, in addition to a Eurorack case. The main drawback of this system is its cost. Photo: mki x

This post was inspired by a close reading of Ray Wilson, Make: Analog Synthesizers (2013). A close reading is not the same as a great appreciation. The initial problem with the book is that it is a vehicle to promote Ray’s day job, the production and sale of Music From Outer Space (MFOS) analogue synthesizer kits. Another problem is that the author/ editors confuse slang and humour with an ability to make a text easy to understand. They do not. For people who have English as a second language, these two components add confusion. The book is described as a hands-on dive into the tools, techniques, and information needed for making an analogue synthesizer. Hopefully, this information will be unnecessary for anyone with experience in building synthesizers, so it is only suitable for people lacking this experience.

Some of the negative vibes about Wilson’s project come from his reuse of the company/ product name. Leonard Nimoy Presents Mr. Spock’s Music from Outer Space, the debut album of Leonard Nimoy (1931 – 2015), was recorded in character as Mr. Spock from Star Trek, and released 1967-06.

Much of the book assumes that the interested reader is building an analogue synthesizer from a MFOS Noise Toaster kit. No other kit or project will do. It is that specific. Earlier parts of the book are useful in explaining the differences between analogue and digital synthesizers (and then forgetting about digital synthesizers), the building blocks incorporated into an analogue synthesizer, including voltage-controlled oscillators (VCOs), filters (VCFs) and amplifiers (VCAs) as well as low frequency oscillators (LFOs). There are suggestions about making a workshop suitable for synthesizer production. Some of these suggestions are useful, especially those about modifying equipment to make it more suited in a low cost workspace. Some of the foundation circuits for amplification, biasing, and signal mixing are also useful, as is much of the information about setting up and using a budget electronic music studio.

MFOS’s description of the Noise Toaster even lists the following features (orthography in the original): WILL attract alien visitations – CAUTION ADVISED; WILL DEFINITELY cut into TV viewing time – CAUTION ADVISED; Stimulates plant growth and calms goldfish. While the kit is described as lo-fi, it has a price tag that is excessive for that category: US$ 209 = € 187 = NOK 1793, at the time of writing. Periodic checks indicate that this kit is permanently out of stock.

In the weblog post Tech Ed some helpful, electronic textbooks are discussed. One book that was not mentioned was Forrest M. Mims III, Getting started in electronics. It began life in 1983, but the edition I have, from Master Publishing, is dated 2003. This is a good introductory book, if somewhat dated, that many people will prefer to, say, Harry Kybett and Earl Boysen, All New Electronics Self-Teaching Guide, 3rd edition (2008), or later books based on this.

My advice to a prospective 16-year old synthesizer builder is to begin by reading, and working with the Mims textbook, then go on to Kybett and Boysen. With sufficient theoretical knowledge in place, a Eurorack synth component can be made.

Rather than MFOS, my preference for a starter kit involves open-source Erica EDU DIY Eurorack projects. Erica Synths was founded in Latvia in 2014 by Girts Ozolinš. Originally, these Synths used Soviet parts. That time has passed, mostly. Erica Synths discontinues its legacy DIY eurorack projects, but decided to make them open-source. They made slight changes to module design to eliminate custom/ rare components. However, this was an imperfect process, as some modules still require relatively uncommon ICs. It is claimed that these can be sourced from Erica Synths. Then they created a folder for each project, with Gerber files for printed circuit boards (PCB) and front panels, and complete information/ files to build a module: schematics, including bills of materials (BOM), component placement with values and designators, and assembly manuals. Note: some manuals are designed for older module versions. Open source allows them to be available for personal, educational and/or commercial purposes.

Gerber is an open ASCII vector format, and de facto standard, for PCB designs, including copper layers, solder masks, drilled holes and printed data.

An almost unpronounceable brand name, mki x, is a joint effort between Erica Synths and YouTube presenter Moritz Klein. It claims that its goal is to teach people with little-to-no prior experience how to design analog synthesizer circuits from scratch. Design is the key word in that statement that they want to emphasize. The components in the kit box are not simply meant to be soldered together and then disappear inside a rack. Instead, they claim that they want to take the constructor through the circuit design process step by step, explaining every decision and how it impacts the finished module. A related, but cheaper, approach is to download the manuals, study them, and then decide if one wants to purchase kits.

Starting at 2021-12-28, they are in the process of offering new kits at the rate of one every four to six weeks. A total of 9 kits are planned. When completed this results in a fully-featured modular monosynth: 1) a sequencer, 2) a VCO at €60, 3) a wavefolder (used to shape soundwaves), 4) a noise/ sample and hold (S&H) module, 5) a mixer, 6) a VCF, 7) an envelope generator (EG) at €55, 8) a dual VCA unit at €55, and 9) an output stereo mixer with a headphone amplifier. In addition, a eurorack case with a DIY power supply unit (PSU) is available at €110. Even if a complete kit costs about €700, it should offer greater value for money than a MFOS Noise Toaster!

Kits have a 40+ page user manual that can be downloaded separately, and in advance of any purchase. These provide information about the electronics behind each circuit, also the fundamental principles of sound synthesis. We hope that the project will inspire future engineers and will contribute to the ever-growing diversity of electronic music technology.

The advantage of a Eurorack component, is that it allows one to start with a very simple project that is only part of a functional synth. One can build up construction experience gradually. One can also mix and match components from several manufacturers, or make them.

If one is determined to follow the Wilson trajectory, arrange a conditional sale of a finished MFOS kit-build of a Noise Toaster at cost, at the same time one is reading the Wilson book, and building the kit. The reason for this approach is that once the Noise Toaster is built and sold, the builder is free to decide if s/he wants to build another synthesizer and, if so, the type – without being constrained by the ownership of an existing kit.

My suspicion is that kit builder are seldom content with the simple, but want to construct more complex design. However, a word of caution may be needed. I remember hearing from someone that only the third (or later) iteration of a project actually results in a usable product. The first iteration is overly simple, because one is in the process of developing one’s skills. The second one is overly complex, because with the success of the first project, the constructor is open to anything and everything. The third iteration, involves moderation.

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