The Path to Your MFOS Modular

From Getting Started to Building Your Own MFOS Modular

Article by Ray Wilson

Introduction

Whether you've just decided to find a new and engaging hobby or you're a seasoned analog modular builder this page will have something of interest for you. Where should I start? That's a question I'm often asked and I think this information will provide guidance and help in that area. I'll go over the difficulty rating of the projects as well as the prerequisite skills and equipment necessary to complete the projects successfully.
A bit of advice about age level for projects on Music From Outer Space. I believe that the most basic projects on the site are appropriate for someone twelve years and up if they have an interest in electronics and an electronics mentor to help them. From PC boards to kits none of the MFOS projects come with step by step instructions or documentation. All project documentation is online and can be printed out as necessary to support the completion of the project. There are no step by step directions for any project on the site and builders must know:
On the other end of the spectrum are the seasoned modular builders who often ask more involved questions regarding gate levels, trigger levels, input voltage range, etc. I'll cover some of that information as well but a thorough reading of the schematics and circuit descriptions of any project will answer those questions straight away.
A great way to see MFOS projects in action is to search for the term 'MFOS' on YouTube. You will find a ton of videos from folks who have made an MFOS project and want to show the world what it can do (including my own videos).

Basic Skills and Equipment Required for All MFOS Projects

Here is the list of basic skills and equipment you'll need to succeed with any MFOS project. If, currently, you don't possess these skills spend a bit of time on the Getting Started in Electronics page of my website. There you'll find some resources to help fuel your research.
Although I haven't marked it as required it can be challenging to work on a piece of audio frequency equipment without an oscilloscope. Find someone who has one that will let you use it or will use it along with you. As soon as you can get one, get one. You can also find a version that works with your sound card which is a little better than nothing, but hey better is better. The more involved projects require a minimum DC to 20MHz capable oscilloscope. (digital or analog) for module calibration and trouble shooting. Check craigslist or Amazon to find one. There are a million used scopes out there and, after all, you only need the one.

MFOS Project Difficulty Rating System

Level 1) Beginner Project Required Skills

Can be built using the Basic Skills and Equipment Required for All Projects
Can be debugged with no more than a good multimeter and a signal tracer. I'll bet there are a ton of sites that have plans on how to make a DIY signal tracer (now I'll have to design one). It is essentially an oscillator for injecting signals into your circuit and an amplifier to listen for the signal at various points along the signal chain to see if it is present and "sounds" OK. It is no substitute for an oscilloscope but can be helpful in beginner projects.
Usually requires a friend or relative (or both) with electronic skill as a coach in case something needs trouble-shooting. As much as I'd like to, I am unable to be a trouble-shooting resource for people. I have built every project on the site (some many times) and know that they work when built as presented. I'm not being hard hearted just practical.

Level 2) Intermediate Project Required Skills

Familiarity and experience with line (mains) powered single and dual power supplies. Level 2 projects assume that the user has an understanding of and can provide a power supply capable of adequately powering the project. Most projects require a dual power supply that provides plus voltage, minus voltage and ground. For instance +12V, -12V and ground.
In addition to the Level 1 skills more electronics knowledge and success with previous electronic projects is highly suggested. Understanding of Ohm's law, familiarity with and ownership of (or access to) electronic test equipment is also required.
Level 2 projects require the builder to select and purchase the project's components from an electronics retailer. All MFOS projects include a parts list (also called a BOM or Bill Of Materials) and the builder uses it to find the proper components. The parts are listed as generic components for example: '10K 1/4W Resistor' and not as a part number. The user needs to know that the part is a through-hole leaded part since that is what the PC board expects. Capacitors are listed as ceramic or electrolytic or tantalum but again the builder needs to know from looking at the PC board the lead spacing etc. The user needs to know that caps must have working voltage higher than the highest voltage they will encounter in use. These are the kind of things I mean when I say you need to know how to buy components.
Additionally panel and case making skill and tools are required although people can make a case out of whatever is around if they are inventive enough. Baking pan synth anyone?
An oscilloscope (minimum DC to 20MHz analog or digital) is required for anything above the Level 1 projects.
Trouble-shooting skill or a friend or relative (or both) with electronic skill as a coach in case something needs trouble-shooting. As much as I'd like to, I am unable to be a trouble-shooting resource for people. I have built every project on the site (some many times) and know that they work when built as presented. I'm not being hard hearted... just practical.

Level 3) Advanced Project Required Skills

In addition to the Level 2 skills these projects require the user to have advanced electronics knowledge and trouble-shooting experience and equipment (a good multimeter or two and a good oscilloscope - minimum DC to 20MHz digital or analog).
Additionally, an understanding of how synthesizer modules interconnect and how you plan to integrate the completed MFOS modules or MFOS single board synthesizer(s) you build into your existing set up is required.
I am always open to receive feedback from people who discover errors or omissions in any project's documentation at info@musicfromouterspace.com. I fix them ASAP in most cases.

Alright then... Where do I get started?

Where you start and how far you go all depend on you, your skill level and your desire to learn about electronics and synthesizers in general. Find where you see yourself in the following skill continuum, pick a project, and go for it.

I have absolutely no electronics experience

If you currently have no electronics knowledge or experience I suggest you do some research and learn a bit about electronics in general before attempting any MFOS project. There is no substitute for knowledge and/or experience. So for you folks I'm going to send you off to the Getting Started in Electronics page.
Please come back after you've gained the required Level 1 skills listed above. If you decide to ignore this advice don't blame me if your project experiences result in despair and frustration instead of fun and accomplishment. The old saw "Knowledge is power" is actually pretty doggone true.

I have Level 1 skills and equipment

Alright now you're cooking with gas. Boy is that an old expression... The suggestions for Level 1 builders are all battery powered and are available as complete parts kits with faceplates (except for Battery Powered Function Generator and the Battery Powered Mixer & 1W Amp). All you have to do is follow the directions for the project put the parts in the right place, wire everything up and voila you're making interesting analog electronic sounds. Advanced builders can use a power supply to power the projects if they are familiar with using them.

The only thing you may have difficulty with is choosing which one to build. If you're a total newbie start small and if you have some experience go for the NOISE TOASTER or the Echo Rockit both of which make a wide range of cool sounds for such simple designs running on one 9V battery.

The Weird Sound Generator (WSG)

The 9V battery powered WSG has 6 simple oscillators that can be used to modulate and gate one another. Additionally the oscillators can produce droning sounds and the circuit includes a low pass filter with variable cutoff frequency and resonance. All told, this thing make some pretty weird sounds, thus its name.
If the WSG hasn't set some kind of record by now for the most often built synth-diy project I'd be surprised. I have sold thousands of the PCBs and hundreds of the kits. A lot of people from around the globe have built this project.
For newbies MFOS sells a full parts kit with a professionally machined and screened faceplate for this project. For more advanced builders I also provide just the PCB and/or panel.
You still need to make some type of case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project.

The Alien Screamer

This is a popular 9V battery powered project that consists of a wide range tone voltage controlled oscillator (VCO) and a low frequency modulation oscillator (LFO). The LFO produces several interesting wave-shapes with which to modulate the tone oscillator. Additionally the low frequency oscillator can be used to elicit sync effects from the VCO. The unit includes a 1W amplifier and 2.25" speaker for street performances or getting out of jury duty.
For newbies MFOS sells a full parts kit with a professionally machined and screened faceplate for this project. For more advanced builders I also provide just the PCB and/or panel.
You still need to make some type of case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project.

The NOISE TOASTER

The NOISE TOASTER is the most complex of the Level 1 projects, component count-wise and functionality-wise. The 9V battery powered NOISE TOASTER is a reprise of a sound generator I designed way back in the early 1980s. It has a voltage controlled oscillator (VCO), a simple voltage controlled low pass filter (VCF), a low frequency oscillator (LFO), an AR generator (manual gate or repeat modes), a low frequency oscillator (LFO) with 3 selectable waveforms, a simple voltage controlled amplifier (VCA) and a white noise source. It has a simple normalized switching scheme for routing the VCO and white noise through the VCF and VCA. Additionally the VCO, VCF and VCA can be modulated by the LFO and/or AR generator. It makes a myriad of sounds and includes a built in 1W amplifier and 2.25" speaker for coffee shop work... or the library.
For newbies MFOS sells a full parts kit with a professionally machined and screened faceplate for this project. For more advanced builders I also provide just the PCB and/or panel.
You still need to make some type of case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project.

The Echo Rockit

The Echo Rockit is a great sound maker all by itself or you can feed your guitar or keyboard through the unit's 12dB per octave resonant VCF and PT2399 based echo processor. The Echo Rockit requires the same skill level as the NOISE TOASTER. The Echo Rockit boasts: Simple 9V Battery Supply, External Input with Mic/Line Capability, Put external signals through VCF and Echo, Resonant Low Pass VCF Doubles as Sine Oscillator, External Voltage Control of VCF Cut Off Frequency, Echo Effect Processing (Volume, Delay, Repeat), LFO Has Triangle and Square Waves, LFO Has Low and High Range, LFO Modulates Cut Off Frequency, LFO Modulates Echo Delay Time, Internal Oscillator for VCF Excitation
For newbies MFOS sells a full parts kit with a professionally machined and screened faceplate for this project. For more advanced builders I also provide just the PCB and/or panel.
You still need to make some type of case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project.

Battery Powered Function Generator

This 9V battery-powered function generator outputs sine, square, and triangle waveforms. The frequency is adjustable from about 20 Hertz to about 11KHz and the output level can be varied from 0 to about 3V, peak to peak. The unit is powered from a nine volt battery making it perfect for young hobbyists.
For newbies MFOS sells a full parts kit for this project. For more advanced builders I also provide just the PCB.
You still need to make a faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project.

Battery Powered Mixer & 1W Amp

This project results in a cool little battery powered amplifier you can use to show your friends what your project sounds like and you won't even need an outlet. Since it runs on one 9V battery it's perfect for the coffee shop, lunch room, picnics, company picnics (an entirely different affair), scenic outings, other outings, mountain climbing expeditions, sky-diving, quiet sound-ins, quiet rap battles, moon landings and many other situations that I can't think of right now but I hope you do.
MFOS sells a PC board only for this project.
You still need to make a faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project.

I have Level 2 skills and equipment

The MFOS Sound Lab Mini-Synth

The Sound Lab Mini-Synth is the first project I supported with a PCB when MFOS began. The Sound Lab can be powered with 2 9V batteries or a line (mains) powered dual power supply up to +/-15V and ground. It is more capable than the Level 1 projects in that its two VCOs can be calibrated to track 1V per octave over an octave or two. The levels of the two oscillators and the white noise can be adjusted via the unit's signal mixer prior to processing by the unit's VCF and VCA. The Mini-Synth's VCF is more advanced than those found in the level one projects and uses the venerable LM13600/LM13700 dual transconductance amplifier to provide voltage control and selectable low pass or band pass output. The LFO is also a bit more advanced than the Level 1 projects and provides triangle and square wave outputs. The AR generator can be gated externally and the VCOs can also be controlled via externally applied control voltage. The VCA is more advanced than in the Level 1 projects and also uses the LM13600/LM13700. The Sound Lab Mini-Synth requires an external amplifier.
This project has also enjoyed wide popularity and synth-DIY enthusiasts the world over have found it a very fun and engaging project.
MFOS sells a full parts kit for this project. For more advanced builders I also provide just the PCB. MFOS does not sell a panel for this project.
You still need to make some type of panel and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project. If batteries are not used a line powered dual power supply (+/-9V to +/-15V) must be provided for this project.

MFOS 10 Step Sequencer

This project results in a cool 2 to 10 selectable step sequencer which can be used to modulate any voltage controllable module. This makes a great source of modulation for the Sound Lab Mini-Synth or any of the single board synths or modular synth ideas listed in the Level 3 (Advanced) project list.
MFOS sells a high quality PCB for this project.
You still need to make some type of faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project. A line powered dual power supply (+/-9V to +/-15V) must be provided for this project.

MFOS Micro Sample and Hold

This project requires one LF444 op amp and some N-Channel JFETs to build a simple small sample and hold circuit that can be used to modulate the VCF and VCO of the Sound Lab Mini-Synth (or any other voltage controlled module). The project can be powered using 2 9V batteries or a line powered dual supply.
MFOS sells a high quality PCB for this project.
You still need to make some type of faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project. If batteries are not used a line powered dual power supply (+/-9V to +/-15V) must be provided for this project.

MFOS Envelope Follower Filter

This is a simple 9V battery powered project that can be used with a guitar or keyboard to add a signal level dependent wah sound. The louder you play the more pronounced the harmonic shift becomes resulting in an auto-wah effect. This is a fun little project for guitar or keyboard players.
MFOS sells a high quality PCB for this project.
You still need to make some type of faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project.

MFOS Mini-Controller

This is a great first keyboard project with which to control your home-brew analog synth. It's a great companion for the MFOS Sound Lab Mini-Synth. The project can be powered using 2 9V batteries or a line powered dual supply.
MFOS sells a high quality PCB for this project.
You still need to make some type of faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project. If batteries are not used a line powered dual power supply (+/-9V to +/-15V) must be provided for this project.

MFOS Stereo Panning Mixer

This is a great mixer project for your home-brew analog synth. This four channel mixer can grow to more channels and the project's page shows you how to expand using more Stereo Panning Mixer PCBs.
MFOS sells a high quality PCB for this project.
You still need to make some type of faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project. A line powered dual power supply (+/-9 to +/-15V) must be provided for this project.

MFOS 1V/Octave Calibrator

If you plan to progress into 1V per octave modules this makes calibration of them much simpler. This unit outputs 0 through 7 volts in precise 1V steps which comes in very handy when you're calibrating VCOs or VCFs whose resonance can be adjusted to produce a 1V per octave sine wave.
MFOS sells a high quality PCB for this project.
You still need to make some type of faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project. A line powered dual power supply (+/-12V) must be provided for this project.

MFOS Synth-DIY Experimenter Board

This is a fun project that results in a totally cool sound generator. The oscillators in the unit are not for musical applications (they do not track 1V/Oct) but provide a tone source for sirens, birds, spaceships, (you name it) and the remainder of the modules are all simple designs intended to give a person new to sound boxes a nice complement of modules to interconnect and experiment with. Make a ton of sounds. Can be used with your SW sampler to produce all manner of whacky sounds that you can then play on your keyboard! The project can be powered using 2 9V batteries or a line powered dual supply.
MFOS sells a high quality PCB for this project.
You still need to make some type of faceplate and case for this project but it can be as simple as a cardboard box to get started or if you have carpentry tools and skills, a nice woodworking project. If batteries are not used a line powered dual power supply (+/-12V) must be provided for this project.

MFOS Wall Wart Dual Power Supply

This is a really simple power supply that can power up to 10 to 15 modules or any project on the site that requires a dual power supply. It takes the output of an 9 to 15V AC output wall wart and converts it to clean +/-12V and ground for your project.
MFOS sells high quality PCB for this project as well as a parts kit that includes the PCB (does not include the AC output wall wart).
MFOS does not sell a case or panel for this project. The power supply is normally housed within the case of the project it is powering.

MFOS LM317/LM337 Based Power Supply

This power supply can power up to 15 to 20 modules or any project on the site that requires a dual power supply of between +/-12V to +/-15V. The project requires a 1A to 2A capacity center tapped transformer with output voltage between 24 VAC and 36 VAC. The output of the supply is adjustable.
MFOS sells high quality PCB for this project as well as a parts kit that includes the PCB (does not include transformer).
MFOS does not sell a case or panel for this project. The power supply is normally housed within the case of the project it is powering.

I'm a Level 3 Synth-diy Jedi Master

MFOS Sound Lab ULTIMATE

The Sound Lab ULTIMATE is a single board synth project with a full complement of analog synth modules. This project results in a musically useful three VCO synth with AR and LFO modulators and the subtractive synth elements you expect (Low Pass VCF (sine oscillation capable) and VCA). Additionally the unit has a sample and hold for cool sonic effects. Please see the project page for full details.
MFOS sells a PCB only for this project. Additionally the catalog page lists the harder to find components as Add-Ons that you can conveniently add to your cart. I suggest you try and find the components yourself before ordering. That way in case you run into difficulties finding them you'll know which Add-Ons to put in your cart when you order. Otherwise you may have to order again and incur another shipping and handling charge.
A case and a line powered dual power supply (+/-12V) must be provided for this project.

MFOS Sound Lab ULTIMATE EXPANDER

The Sound Lab ULTIMATE EXPANDER is a single board adjunct to the Sound Lab ULTIMATE that adds a number of modules advanced synthesists will find useful. An ADSR envelope generator, State Variable VCF (sine oscillation capable), VCA and many other modules are provided by this project. Please see the project page for full details.
MFOS sells a PCB and Two Faceplate set for this project. Additionally the catalog page lists the harder to find components as Add-Ons that you can conveniently add to your cart. I suggest you try and find the components yourself before ordering. That way in case you run into difficulties finding them you'll know which Add-Ons to put in your cart when you order. Otherwise you may have to order again and incur another shipping and handling charge. PC board and faceplates can also be purchased separately.
A case and a line powered dual power supply (+/-12V) must be provided for this project.

MFOS Sound Lab Mark II

The MFOS Sound Lab Mark II is the latest single board analog synthesizer product offering from MFOS. It has two musically accurate VCOs, White Noise Source, Signal mixer with external input, two AD envelope generators, Sample and hold, VCF (sine oscillation capable), VCA, LFO. Please see the project page for full details.
MFOS sells a PCB and 17" x 7" Faceplate for this project. Additionally the catalog page lists the harder to find components as Add-Ons that you can conveniently add to your cart. I suggest you try and find the components yourself before ordering. That way in case you run into difficulties finding them you'll know which Add-Ons to put in your cart when you order. Otherwise you may have to order again and incur another shipping and handling charge. PC board and faceplates can also be purchased separately.
A case and a line powered dual power supply (+/-12V) must be provided for this project.

MFOS 16 Channel Sequencer

The MFOS 16 Channel Sequencer is a fully featured 4 to 16 step sequencer project. You can expand the project by adding additional analog channels, quantized step durations, and additional LED/Gate driver boards. Please see the project page for full details.
MFOS sells PC boards to support this project as well as Add-On components for some of the chips and precision voltage sources. PCBs available: Digital Control PCB, Analog Routing PCB, Quantized Clock Driver, and Gate/LED Driver. The simplest combination is the 2 PCB set (one Digital Control PCB and one Analog Routing PCB). MFOS does not sell a faceplate for this project.
A case and a line powered dual power supply (+/-12V) must be provided for this project.

MFOS SUBCOMMANDER

The SUBCOMMANDER is a very cool project for both guitar and keyboard players. It is modeled after the totally cool effect that Electro-Harmonix came out with years ago. It accepts the input from a guitar or keyboard, provides audio to gate capability and a full host of sound modifiers through which to process the input. Additionally the unit provides a monophonic sub-octave that augments the sound of the signal being processed. This unit can be powered with 2 9V batteries but a line powered dual supply is recommended.
MFOS sells a high quality PCB for this project.
If batteries are not used a line powered dual power supply (+/-12V) must be provided for this project. A case and faceplate must be fabricated for this project.

Building an MFOS Modular Analog Synthesizer

I can confidently say that an MFOS modular synthesizer will hold its own against any synthesizer out there. You can start as simple as you like and build up to a multi-cabinet monster if you have the interest, resources and time.
Building an MFOS modular synthesizer requires the builder to have a complete understanding of synthesizer principles.

The MFOS lineup of analog synthesizer modules includes the following:

MFOS sells high quality PCBs for all of analog modular synth projects. Boards are professionally manufactured, double sided copper, plated through holes, solder masked, and all pads lead-free solder plated. I often get feedback from customers remarking about the high quality of the PCBs MFOS provides.
Builders must fabricate and label the module faceplates.
I have designed several faceplates (including wiring diagrams) for many of the MFOS synth module projects using the 3.5" x 8.75" format. If the one you need is missing let me know and I'll add it.
MFOS 3.5" x 8.75" Panel Templates
Typically builders fabricate wooden cases designed to hold about 10 modules each. Each of these synth-cabinets contains a power supply capable of powering the cabinet's modules (750 to 1000 mA). In each cabinet the power supply output is run to power busses which make powering the installed modules more convenient. Some builders like to use connector schemes to accomplish the connection of the modules to the power buss. I prefer to strip solid #12 copper wire and run 3 lengths up both sides of the cabinets using wooden brackets. I keep the power busses about 1 inch apart and I am very careful not to short the busses during construction or modifications. I run 20 gauge stranded wire from the supply to both sets of busses. I do not add caps to the power supply busses because all MFOS boards have bypass capacitors. As I install modules I solder each one's power supply wires to the #12 solid copper wires. This is not as convenient if you are constantly changing out modules for adjustment or replacement but I NEVER have connector issues.

Interfacing Your Synth With MFOS Gear

Interfacing MFOS gear with your synthesizer is not hard but you need to know the expected gate and trigger requirements of your synth in order to successfully integrate it with MFOS gear. MFOS gear emits gate and trigger pulses that usually start at ground and rise rapidly to the MFOS module's positive supply voltage (or very near it). MFOS gear control voltages can go higher than +/-5V which is the limit for some commercial analog gear. In order not to put too high of a voltage into your gear this article shows how to limit the CV output of MFOS gear to +/-5V. Lastly your gear may not have a high enough gate or trigger voltage to gate and trigger MFOS modules. I show how to boost low gate and trigger levels to those needed by MFOS gear. MFOS gear can more than likely take the control voltage output by your synth with no problem but do not apply control voltage to MFOS gear that is higher or lower than the MFOS modules's positive or negative supply voltage respectively.

Read More About Interfacing With MFOS...

NEVER CONNECT THE RAW MFOS GATE OR TRIGGER OUTPUTS TO YOUR MODULAR WITHOUT KNOWING ITS VOLTAGE REQUIREMENTS AND/OR LIMITATIONS. PRIOR TO DRIVING YOUR MODULAR'S MODULES WITH MFOS MODULE VOLTAGE OUTPUTS ASCERTAIN ITS EXPECTED RANGE OF CONTROL VOLTAGE. COMMON SENSE... IT'S ALWAYS IN STYLE.