The Crowminius Synthesizer Is A $700 Minimoog Model D Clone

Developer Scott Rider, aka Old Crow, has announced a Kickstarter project to fund the production of the Crowminius – a $700 Minimoog Model D inspired synthesizer. 

The Crowminius is a complete desktop monophonic analog music synthesizer, inspired by Dr. Robert Moog’s legendary Minimoog model D.

It’s designed to be constructed from standard components, with no esoteric parts, and fit into an aluminum attache case for easy portability.

The Crowminius features an Atmel MIDI control front-end based on the ATMEGA328P chip, the same as used in the popular Arduino Uno. The open-source firmware supports MIDI note, velocity and aftertouch as well as MIDI pitch and mod wheel support. An optional LCD can be installed to monitor system functions, but it is not necessary.

The unit can also be operated from pitch control voltage and choice of voltage trigger or switch trigger jacks, for interfacing with both modern and vintage analog gear.


The Crowminius, above, features three full-range oscillators (tone generators) that each can be set via rotary switches from sub-sonic frequencies through a set of “organ stops” (octaves) from 32′ (bass) to 2′ (high soprano). Each oscillator has six waveforms also set by rotary switch to provide the harmonic spectra used to create various sounds.

Oscillators 1 and 2 each feature individual pulse-width modulation generators–a feature not found on the vintage model D–and oscillator 3 can be set to act as a “control oscillator” to provide vibrato and filter modulation by use of the on-board modulation control or by MIDI modulation commands from a remote controller.

The Crowminius has an on-board white/pink/red noise generator that can be used to create audio effects such as wind and surf sounds, but the noise source can also be used as a modulation source. Another feature included on Crowminius that makes use of the noise generator is a “sample/hold” circuit that uses oscillator 3 in control mode as a clock to trap the noise signal levels and provide a series of stepped random modulation voltages.

These signals are all presented to the 4-pole ladder filter and control amplifer, an all-discrete transistor (no chips!) circuit combination that defined the sound of 1970s progressive rock. The filter has dedicated controls for tracking and modulation, and the filter and amplifier each have their own contour generators to control the dynamics of your sound.

Other features include an external audio input into the filter, a “locking” portamento/glide circuit for moving from note to note in solo style, and a “decay mute” feature which allows immediate muting of notes when keys are released. Both the glide and decay mute functions can be operated by external footswitches if needed.

Finally, two essential performance features are provided:

  • A reference tone at A-440 (“concert A”) can be enabled for precise instrument tuning. This tone is created by the microcontroller using a direct-digital synthesis algorithm that outputs a very accurate PWM-modulated sine tone.
  • Secondly, a dedicated headphone jack and headphone volume control allow the performer to mute the instrument, set up a new voice patch, tune up and and un-mute right back into a live session without disrupting the performance.

The entire Crowminius system is powered from a single 12VAC, 500mA wall-pack power supply, with provision to allow the use of two supplies for improved supply operation.

The Crowminius Synthesizer Options

The Crowminius was originally presented as a DIY project to synthesizer enthusiasts in early 2015. Because many people have asked about a pre-assembled version. it was decided to offer a production run, with an initial goal of shipping 100 units.

To this end the design has already been reworked for surface-mount assembly, with the production prototype being hand-built and fully tested before committing the SMT assembly line to production.

The Crowminius is available to project backers for $700, complete with case and power supply, factory-calibrated and ready for immediate use. Includes engraved front panel. The through-hole PCB is also available to backers for US $100. See the project site for details.

29 thoughts on “The Crowminius Synthesizer Is A $700 Minimoog Model D Clone

  1. Hmm… I wonder if it would survive a lawsuit. God forbid, but if Moog went after Arp for having similar filters, what would keep them from following suit here?

    1. I don’t think that’d be a problem nowadays. Every synth maker and their brother has their own “4-pole ladder filter” clone (or dsp emulation). Plus there have been more than a few full fledged Mini clones that have come out over the years.

    2. What are you thinking that they would sue about?

      Patents last 20 years, and this project isn’t copying their trademarks or look.

  2. ARP did it when the patent was live. It has long since expired. The only thing I cannot (and would not) do is use any branding that is Moog IP. –Crow

    1. does that circuit board look like it could be wired point to point? And how exactly does point to point wiring improve the sound?

  3. Any chance of the front panel being made available alongside the PCB I wonder? The options are PCB or full version.

  4. Would be nice if the front panel enclosed the PCB entirely… would looks more finished and less “KIT” DIYish

    1. yeah this literally is what is throwing me off from getting it. I’d rather just save a little more for a voyager or sub 37.

      1. The FAQ says the front panel will cover “most” of it. Also I may be missing it, but are there decay (release) switches anywhere to set a release based on the decay time?

    2. Scott did reply when I asked this.

      The production model will have a full panel that covers most of the PCB

      I’m in!

  5. scott… please, more generous knob spacing. The sound is great, but ergonomics matter too!

  6. I would pick one up in a heartbeat if he took the time to finish his design… As an actual touring musician I would never bring an exposed pcb synth on the road. That’s an extremely bad idea. if it’s about keeping costs low, I think the sacrifice outweighs the reward. Seriously… Add a reward tier for a finished product THEN let people know about the fundraising campaign.

    1. One can imagine that the touring musician who wants a finished product he can take on stage with confidence is not the target audience of this synth. It’s probably part of the design philosophy that you will have to build your own enclosure if you want one.

      1. @Random Chance

        Portability was featured prominently in the article and video. So it’s not being touted as a studio only piece. I’m not sure if they know exactly who their target audience is.

        That said, It’s a nice sounding synth and I would certainly pick one up in a nice rackmount enclosure if they went that route.

  7. To clarify, the crowminius project has been alive for more than a year now. Many people have made their own enclosures for the bare PCB version, the completed synth from the kickstarter campaign is just one of the newest iterations of the project.

    There are technical reasons why the PCB isn’t fully covered, but covered or not, this is one lush sounding synthesizer!

  8. Awesome, truly awesome and looks good, just wondering how you would cover that PCB? Personally I’d make a Keyboard unit out of it, but that’s a whole-lotta PCB to cover = one FAT synth hah

    OH SNAP a Eurorack version:

  9. DC power would have been sooo much better! Hard to make a battery do AC without weird things being needed.

  10. Looks good to me.
    From the website:

    The delivery version of the Crowminius will have a larger panel that covers most of the board.
    Pictured in the project is the production prototype with a partial panel just in case circuit values needed adjustment in the testing phase.

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