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u/keyandcableco

r/PCB r/minichord r/pianotech r/UnusualInstruments r/midi r/functionalprint r/AskElectronics r/synthdiy r/Omnichord r/CircuitBending r/Synths4Sale
minicontrol by The Key & Cable Co.
▲ 6 r/minichord

minicontrol by The Key & Cable Co.

minicontrol: every minichord parameter on one screen, plus bulk edits and backups → https://minicontrol.keyandcable.com

It's a fork of Ben Poilve's minicontrol. It's less feature-rich than minichord Sound Lab, so go there to learn what each setting does. This is for when you just want to see and tweak everything at once.

New:

  • Bulk edit: set something across all 12 banks at once (e.g. every knob's target), and save the set as a shareable profile
  • Reorder banks by dragging, and back up / restore all 12 to one file (same files as Sound Lab)
  • Settings split into submenus (sound vs. voicing/layout), plus the newer firmware settings
  • A few themes, and it installs as an app

Needs Chrome or Edge (Web MIDI). The bank tools and newer settings need the test-allFeatures firmware.

minicontrol.keyandcable.com
u/keyandcableco — 13 days ago
▲ 8 r/minichord

minichord arcade

> Note: some of these features need the unofficial test-allFeatures firmware. With the stock firmware the games still play, but these parts are marked on their title screens and left out: > > - Knob steering in Chord Breakout, Fifths Defender and Chord Stack (the "knobs send MIDI" setting, firmware 17); the mouse and arrow keys work without it > - Key bars in Chord Invaders (the key change combo) > - Slash chord levels in Chord Invaders and Chord Breakout > - Minors and modes in Harp Command (the custom harp scale) > - The double tap flipping the modifier between sharp and flat

The arcade

  • Chord Invaders: chord symbols fall through a starfield; play each on the buttons before it lands. Key bars fall too, set with the key change combo, and later levels add sevenths, slash chords and Barry Harris.
  • Harp Command: Missile Command for the harp. Notes fall toward twelve cannons, one per string; pluck the right string to shoot each one. Levels climb through the chromatic harp, major keys, scale degrees, solfège, minors and modes, and reading notes on the staff.
  • Chord Snake: steer a snake with the harp as a d-pad (standard strip or keymaster) to eat spelled notes; when the ones you're carrying spell a chord, play it to cash them in.
  • Chord Asteroids: play a chord rock's chord to crack it into its notes, then pluck each note on the harp to shoot it down before it reaches your ship.
  • Chord Stack: falling note pieces on a twelve-column board, one column per pitch class. Slide them to transpose (harp, keys, or a knob as the dial), invert them, and play the chord a row holds to clear it.
  • Chord Breakout: Arkanoid with chords. A knob steers the paddle; the ball cracks chord bricks, which break only if you play the chord before the ball comes back.
  • Fifths Defender: Tempest on the circle of fifths. Turn a knob to aim down a key's spoke and play that key's chord to fire; later levels fire with the relative minor, the dominant seventh, or the key's note on the harp.

Playing on the minichord

  • The harp as a controller: the standard strip or the keymaster grid read as a d-pad (up, down, left, right, A, B)
  • Knobs as controllers: new firmware setting "knobs send MIDI" (address 238, firmware 17) sends the three knobs as CC 20–22; one chosen knob steers, wobble ignored, mouse off while the knobs are live
  • Keyboardless title screens: a column's major button starts that level, minor sets the speed, 7 switches game
  • Double tap flips the modifier between sharp and flat, and the chord games set the modifier for the chord you need next

The cabinet

  • High scores: a board for every game, initials entered arcade-style, shared online with a local fallback; minichord players only, and not with beginner mode on
  • Beginner mode: the minichord on screen, lighting what to press: chord buttons, the modifier, a slash's bass, and the harp's string (strip or keymaster plate)
  • CRT screen option: scanlines, vignette, colour fringe, a rolling band
  • Full screen from a corner button or F
  • Game over returns to the title loop after 25 seconds
  • Faster frames: an automatic light mode on slow machines, and smoother scrolling
u/keyandcableco — 18 days ago
▲ 9 r/minichord

Chord Invaders Game

There is now a High-Score system -- leave your initials if you make it to the top players!

Playable on stock firmware, or without a minichord at all.

I promise I'll stop spamming the sub now :)

chordlab.keyandcable.com
u/keyandcableco — 18 days ago
▲ 7 r/minichord

Unofficial build, part two: automatic voice leading, chord buttons that keep up with your fingers, edit profiles, temperaments, 19 and 31-EDO, MPE, and live notation

Follow-up to my earlier post. Same deal as before: this isn't official firmware, it's my own build of changes that are still in review, and anything wrong with it is mine. Same caveat about the LLM help too: tested on hardware, understood, not every line typed by me.

u/beniboy1: still no rush. Most of this is in PRs, and some of the playing-feel fixes below are small and stand on their own without any of the tuning stuff.

u/alexandra-thaler: similarly, no pressure or rush here, I just have an undying curiosity to fulfill and your site is now victim :D

Back up your banks before you flash. Same as last time: Sound Lab does all twelve into one file.

Two corrections to the first post

Master tuning now lives in each preset. Last time I said it was stored separately from your presets. Ben's rule for the minichord is that everything lives in the preset, so it's an ordinary preset setting now, and a preset can carry its own tuning. If you'd set a tuning on the old build, check it after flashing.

Knobs on discrete settings are narrower now. The fix that made knobs work on things like inversion and key signature was also catching settings that are stored as whole numbers but are really continuous: release, attack, filter frequency. Several factory presets have those on their alternate knobs, and those knobs would have swept the whole range instead of around the preset's own value. It now only applies to genuine choices (waveforms, modes, inversions, keys), and every factory preset's knobs behave exactly as on Ben's firmware.

Voice leading

This is the one I'm most excited about.

Normally every chord is built upward from its root, the same way every time. So C major to A minor moves all four voices and jumps, even though the two chords share two notes. That's how it has always sounded on the minichord, and it's the giveaway of chords played by button rather than by hand.

Turn voice leading on and each chord takes whichever voicing of itself moves the least from the chord that's still sounding. C to Am: two voices simply hold, one steps up to the A. The rules are the ones a choir sings by:

  • the voices never cross, so the bottom voice stays the bass and the top voice stays the melody
  • every note of the new chord is present, so a seventh never gets dropped for a doubled root
  • the total movement is as small as it can be

A range setting decides how far the chords may drift from where the buttons would normally put them. Small keeps them anchored; larger lets a progression wander further before it pulls back.

Why it matters outside the minichord: it all goes out over MIDI. Play a progression into your DAW and what you record is a smoothly voice-led progression, the kind you'd otherwise need to know voice leading to write. You don't need to know anything about it. Pick the chords with the buttons and the voicing is handled.

Turn on MPE output as well and each voice goes out on its own MIDI channel, always in the same order from bottom to top. Split by channel in your DAW and you have four separate lines, like the four parts of a choir, ready to give to four different instruments. Strings, a vocal pad, a brass section: a chord progression becomes an arrangement.

It also teaches. With Sound Lab's staff open, you can watch the voices move as you change chords: which notes hold, which step, and where each voice goes. Turn it off and play the same progression, and you see the root-position version jump around by comparison. It's a hands-on way to learn how chords are voiced and how the parts move between them.

What it doesn't do: it leads from the chord that's still sounding, so a chord played into silence starts in root position. Legato changes (below) or hold mode keep the chain going. It minimises movement; it doesn't plan ahead or follow the stricter textbook rules like avoiding parallel fifths. Slash chords are left alone since they name their own bass, and it replaces the inversion and spacing settings while it's on. It works in 19 and 31 too.

Playing feel

These are the ones I'd most like people to try, because they apply to everyone, not just people who care about tuning.

Legato chord changes. Moving from one chord to the next, your fingers overlap for a moment: the next button goes down just before the last comes up. The firmware read that overlap as a slash chord, so you got a bass blip, and then the new chord often didn't take at all until you let go of everything and pressed again. Now a slash needs a deliberate 60 ms of overlap, and rolling C to F to G without fully releasing gives you three clean chord changes. Letting go of the slash bass puts the plain chord back.

Light presses. A press that's a bit light could flicker open for a few milliseconds and re-sound the chord. Button readings now have to settle before they count, which also fixes the maj7-turning-into-major bug from the first post more thoroughly. Latency is the same.

Chords stop when you let go. Chord voices only released once they'd reached the sustain part of their envelope. Let go during the attack or decay and the chord played the rest of its shape first. On the factory presets that's up to about 0.4 s; on a slow pad with a long hold it was seconds. Now the release starts when your hand leaves the buttons.

Filter sweeps under a held chord. Turning a knob assigned to the chord filter did nothing until you played the chord again. It now moves the filter on the chord that's ringing.

The key change combo is quieter and sticks. Picking a key could sometimes also play the chord on that button; it can't now. A key you pick is saved like a knob move, and Sound Lab hears about it.

Edit profiles

Last time I showed the bulk edit: pick a setting, pick a value, apply it to all twelve banks. It turns out the edits I make that way are mostly the same handful, over and over. So you can now save a set of them as a profile and apply the whole set again in one go.

A profile only touches the settings it names and leaves everything else in every preset alone. That's the difference from a backup. A backup replaces all twelve banks with what they were; a profile layers a few of your own preferences on top of whatever sounds are there.

The ones I use:

  • Sometimes I want to reset every preset back to the defaults, but with the mod knob doing the same thing across all of them. Load the defaults, apply the profile, done.
  • The LED dimmed to 0.9 on every preset.
  • One I call "teaching" sets the harp to scale per chord on every preset, among a few other things, so whatever preset a student lands on, the harp is always playing the right notes for the chord.

Applying a profile stages its settings like any other bulk edit, so you see exactly what it's about to change, can undo any of it, and nothing reaches the minichord until you hit Apply.

Profiles export and import as files, so they can be shared. If you've worked out a setup you like (knob assignments, a double tap target, a harp mode), you can hand someone a file instead of a paragraph of instructions, and it goes on top of their own presets without touching their sounds.

Tuning

Temperaments. Ten twelve-note tunings: equal, quarter-comma and sixth-comma meantone, five-limit just, Pythagorean, and the well temperaments a piano tuner would set (Werckmeister III, Kirnberger III, Vallotti, Young, Kellner). They're anchored on C, so the unequal ones sound different in different keys, which is the point. A stays at your master tuning. Switching temperament while a chord is ringing glides it to the new tuning instead of jumping.

Hold a major chord and switch equal to meantone. The third stops beating.

19 and 31-EDO. The octave divided into 19 or 31 steps, so C♯ and D♭ are finally different notes. The chord buttons, sharps and flats, the harp modes and transposition all work in steps of the division.

Chords that need them. The alternate chord layout's catalogue is now 29 chords, adding the just sonorities that 19 and 31 are really for: supermajor, subminor and neutral triads, the harmonic seventh, neutral and subminor sevenths, the utonal tetrad, the harmonic ninth, the otonal hexad, a just augmented triad and a supermajor seventh. They're listed next to their twelve-note counterparts so they're easy to find. In twelve they round to the nearest ordinary chord; in 31 they sound like themselves. Scale per chord gives each one a scale built from its own tones, so the harp stays in the chord's tuning.

MPE output

Off by default. Turn it on and every voice gets its own MIDI channel and its own pitch bend. Glide records into your DAW as a real bend curve, and temperaments and 19/31 pitches arrive exactly, instead of rounded to the nearest semitone. Your host needs to understand MPE.

Sound Lab

The interface build has grown along with the firmware.

  • Live notation under the Play mirror. A staff with what you're playing, the key signature, and the chord's roman numeral.
  • Spelled properly. In C♯ major the chord reaches E♯ and B♯, not F and C; keys past seven sharps get real double sharps; a diminished seventh is spelled as one (C E♭ G♭ B𝄫, not A). A chord and the harp's scale can disagree about the same sounding pitch, deliberately, because the chord's seventh and the scale's sixth degree aren't the same thing.
  • Microtonal notation for the just chords, with three conventions to choose from: by degree, meantone (the Huygens-Fokker way), or Helmholtz-Ellis ratio notation. In 19 and 31 this needs MPE output on, because plain MIDI rounds every note to the nearest semitone and there's nothing exact to spell. The Play screen tells you when it's missing and has a button to turn it on.
  • Controls for everything above: voice leading, temperament, MPE, the full chord catalogue.
  • More reliable bank handling. Every bank read is checked against the bank it asked for, and a bank's name follows what's actually in it.
  • The rhythm mirror now locks onto the rhythm engine only, not onto chords you play by hand.

Getting it

Same links as before, both updated.

Firmware: https://github.com/keyandcableco/minichord/blob/test-allFeatures/firmware/firmware.hex

Interface: https://keyandcableco.github.io/minichord-soundlab/

Chrome, Edge or Opera for the interface, and the Teensy Loader for the firmware, same as last time. Reverting is still just flashing Ben's firmware.hex.

Here's a fun way to play around with the voice leading and MPE/temperament features -- the minichord lab. Still a work in progress!

If you try it

As before, the PRs are the useful place for feedback, since that's what Ben reads. The things I'd most like to know:

  • Voice leading: does it land where you'd have voiced the chords yourself? Where does it choose something you wouldn't, and what range setting do you settle on?
  • Do legato chord changes feel natural? Is 60 ms the right amount of overlap before a slash kicks in, or should it be longer or shorter?
  • On your slowest presets, is a quick tap now fading out when it should, or did you rely on the old behaviour?
  • If you play in 19 or 31: do the just chords sit where your hand expects them, and are the harp scales over them right?
  • Which temperament do you actually leave it on?

Built from Ben's source under its BSD licence. Copyright 2024 Benjamin Poilvé. Interface is Sound Lab by MinichordDrawn, CC-BY-NC-4.0. Neither of them has endorsed this build.

reddit.com
u/keyandcableco — 21 days ago
▲ 26 r/minichord+1 crossposts

The 8Bit 8asterd — a 9-voice MIDI synth built on three AY-3-8910 chips, with a playable browser emulator

Three General Instrument AY-3-8910s driven by an Arduino Leonardo — the PSG from the Intellivision, Vectrex, MSX, Amstrad CPC and a pile of arcade boards.

This runs on real hardware sitting on my bench, not just in simulation. Tested with genuine AY-3-8910A chips and with the Yamaha YM2149 equivalent, which drops straight in.

Play it in your browser. All free and open: https://keyandcableco.github.io/8bit8asterd/

Source: https://github.com/keyandcableco/8bit8asterd

Grew out of Ian Harvey's single-chip Instructables build and Doge Microsystems' dual-chip module.

Drums demo video

Why it sounds crunchy. Here's everything an AY gives you:

  • Three square voices, no filter
  • One noise generator, shared across all three channels
  • One envelope generator, also shared
  • A 4-bit logarithmic volume DAC
  • An integer tone divider, so pitch resolution gets coarse up high

Run nine voices and a drum kit through three of them and they audibly fight. Two drums on the same chip contend for one envelope. Noise and tone share a single amplitude register, so there's no way to turn the noise down on its own. The firmware leans into all of it — one section deliberately writes junk to the chips behind the register cache while the voices keep writing what they expect, and you hear the collision.

What's in it:

  • Chord matrix with a strumpad, and a 16-step drum sequencer
  • GM drums with roll, flam, reverse envelopes and per-hit randomisation
  • Ten historical temperaments — meantone, just, Werckmeister, Vallotti
  • Every parameter on MIDI CC, with learn
  • Bluetooth gamepad — chords on the face buttons, drums, effects on the sticks, right stick strums
  • Works on a phone

The emulator runs the same firmware that's flashed on the physical unit, compiled to WebAssembly against emulated chips. Every feature above was developed and tested on the real chips first.

If you open it, load the Bad Ground preset and hold a low chord — that one throws junk at random chip registers on a slow sweep, and it's the clearest picture of what the thing actually is.

What would you add? Hardware version two is in progress and I'm still deciding what earns a physical knob.

u/keyandcableco — 27 days ago
▲ 8 r/minichord

Short demonstration of Chord Spread/Chord Inversion and Scales on the Strings

Short video showing three of the things from the build I posted.

Chord inversions change which note sits at the bottom of the chord. Chord spacing opens the voices out — the minichord has only ever played chords in close position, and this adds the standard drop voicings. The two combine, so inversion picks the bass note and spacing sets the width, and you can sweep both from the knobs while playing. I've got them assigned here to the Mod Pot Main and Alternate for some interesting colors.

Harp scale modes are the one I get most out of. Instead of the strings playing the chord you're holding, they play a scale chosen to suit it — Lydian on a major seventh, Mixolydian on a dominant, Dorian on a minor seventh. The strings are always already right for the chord under your left hand, so you can actually solo over your own progressions. You'll even hear an Augmented chord generating a Whole Tone scale, really cool stuff, nerd 🤓

youtu.be
u/keyandcableco — 1 month ago
▲ 8 r/minichord

Unofficial build: back up your presets to a file, plus a few playing features

Up front: I've had a lot of help from an LLM getting this over the line, so excuse any stretches that read like one wrote them. I've got three kids and these features have been half-finished on branches for the best part of a year — the models have got good enough over that time to actually be useful for this sort of thing, and it's the only reason any of it got finished. Everything here is tested on hardware and I understand what it does, but I'm not going to pretend I typed every line of it.

u/beniboy1 — these are all sitting in PRs on the repo, no rush on any of them. Putting a build up here so people can actually try them and tell you whether they're worth your time.

u/alexandra-thaler -- your minichord app is amazing! I've also got a couple of PRs sitting on your repo if this is something that interests you at all. I don't mean to be presumptuous, I just really wanted to use your interface with these features, and so far it's just fantastic!

Everyone else: this isn't official firmware. It's my own build of changes that are still in review. Anything wrong with it is mine, so bring it here or to the PR rather than the issue tracker.

Reverting is just flashing Ben's firmware.hex back the same way. And backing up your presets is the first thing this lets you do, so do that before you start.

The one I actually wanted

Your whole minichord in a file. All twelve banks into one .json, and back again. Keep a copy before you experiment. Move a setup between devices. Swap a whole set of presets at once.

Changing one setting across every preset

This turned out to be the thing I use constantly and didn't expect to.

There's a banks view showing all twelve at once with their colours. You can drag to reorder them, and name the ones you made yourself so they stop showing up as "unrecognised patch".

But the part I keep going back to: pick any setting, pick a value, apply it to every bank at once. Barry Harris mode on across the board. Every preset into the same key. Reverb dialled back everywhere because your amp is boomier than your headphones. Twelve presets, two clicks, instead of twelve rounds of load-tweak-save.

It stages everything first, so you can rearrange and bulk-set as much as you like and nothing touches the minichord until you hit Apply — and then it only writes the banks that actually changed.

The rest is playing features.

Harp scale modes

Right now the harp strings play the notes of the chord you're holding. Great for strums, but it means the harp can only ever play those four notes, so you can't really solo over your own chords.

Set the harp to scale per chord and hold a Cmaj7 — the strings become C Lydian. Move to Dm7 and they become D Dorian. Move to G7, Mixolydian. The strings are always already the right notes for the chord under your left hand, so you can run up and down the harp while changing chords and never hit a wrong note.

There are also seven fixed scales if you'd rather the harp ignore the chord, and a pentatonic version of the scale-per-chord idea that's even harder to clash in.

A question for anyone who thinks about this stuff: the chord-to-scale mapping is the standard jazz one, but I'm not sure it's the right default for this instrument. Major seventh gets Lydian, which means a ♯4 sitting there every time you hold a maj7 — lovely on a static vamp, possibly too spicy as a default. Plain Ionian would be safer and duller. Dominant sevenths get Mixolydian and minor sevenths get Dorian, which I'm more confident about. Diminished gets the octatonic and augmented gets whole tone, which are the obvious choices but also fairly punishing.

If you play this stuff, I'd genuinely like to know what you'd have picked.

Chord inversions

Root position through third inversion, changing which note of the chord sits at the bottom. Progressions move less and sound smoother. You can change it while a chord is sustaining, so it works as a performance move rather than just a setting.

Master tuning

A4 anywhere from 432.0 to 444.0 Hz, for playing with an ensemble that isn't at 440. Stored separately from your presets so it stays put when you change preset, and it retunes a chord while it's ringing.

Physical key change

Hold both preset buttons and the LED blinks. While it's blinking, any chord button picks a key: seven rows of F C G D A E B, three columns of sharp, natural and flat — all 21 keys, including the enharmonic ones. The LED flashes that key's colour when you pick it. Let go of either button to leave.

Single-tapping a preset button still changes preset as normal.

Knobs that work on discrete settings

Assigning a knob to something like chord voicing or key signature used to do nothing, because of how the range was calculated. Now it works, with a bit of hysteresis so it doesn't flutter between values.

Which means you can put chord inversions on a knob and sweep voicings while you play, which is what I wanted a knob for in the first place.

Getting it

You need Chrome, Edge or Opera. Web MIDI doesn't exist in Firefox or Safari — the page will load and never connect.

Firmware: https://github.com/keyandcableco/minichord/blob/test-allFeatures/firmware/firmware.hex

Right-click, Save As. Flash it with the Teensy Loader app the same way as any minichord update: USB in, headphones in, then push a thin pin into the hole at the back when it asks.

Interface: https://keyandcableco.github.io/minichord-soundlab/

Just open it, nothing to install. It's a build of Sound Lab, the excellent third-party editor by MinichordDrawn, with the new settings added. Hit Connect and it finds the minichord.

You can open the interface before flashing anything — it works as a normal Sound Lab against stock firmware. The new settings just won't do anything yet.

Don't reset your banks after flashing. These are meant to leave existing presets alone and I'd like to know if that turns out to be wrong for anyone. Back up first and you've got a copy either way.

If you try it

Say so on the PR rather than here, if you can be bothered — that's the bit that's actually useful, and it means Ben can see whether any of this is worth merging without having to take my word for it. Links are on the repo.

Things I'd particularly like to know:

  • Is Lydian on a major seventh right, or too much?
  • Does the key change combo trigger reliably for you?
  • Do the other scale-per-chord modes sound right on chords you'd actually play?
  • Is chord inversion 3 useful on triads, or just an octave shift you'd rather have as something else?
  • Anything odd with glide turned up

Built from Ben's source under its BSD licence. Copyright 2024 Benjamin Poilvé. Interface is Sound Lab by MinichordDrawn, CC-BY-NC-4.0. Neither of them has endorsed this build.

EDIT — a few more things since I posted this

Chord spacing. Chords have only ever been played in close position, with the four voices as close together as the chord allows. This adds the standard drop voicings, which take a voice down an octave to open the chord out. Drop 2+4 is the one that sounds like a pianist voicing a chord — on a maj7 the gaps go from 4-3-4 semitones to 7-9-7, spread across two octaves.

It combines with inversions: inversion picks which note is at the bottom, spacing sets how wide it is. Twenty distinct voicings of any chord from two controls, and both work from the knobs while you play.

An alternate chord layout. Three chord buttons give seven combinations and all seven are already used, which is why there has never been a sus4. So there is now a second layout on the same buttons, defaulting to sus4, sus2, 7sus4, maj9, min9, add9 and 6/9. Fourteen chord types instead of seven.

And it is assignable — each of the seven slots can point at any of eighteen chord types. If you never play augmented, put m7♭5 there instead. It is as much about moving chords to where your hand wants them as about having more of them.

An assignable double tap. Two quick taps of the modifier button toggle any setting you choose between two values, and back. Point it at the chord layout and you can switch sets mid-phrase. Point it at Barry Harris mode, or an inversion, or a harp scale — it is the same idea as assigning a knob, applied to a gesture. The LED breathes slowly while it is engaged so you can see the state.

Two bugs fixed along the way, both of which were already there:

  • Holding the modifier to reach a knob's alternate setting used to sharpen whatever you were playing. It does not now — once you move the knob, the modifier is understood as meaning the knob.
  • With hold on, a sustained maj7 would quietly turn into a plain major if you changed almost any setting. The chord buttons do not release at exactly the same instant, so letting go of a two-button combination was briefly read as a one-button combination, and anything that recalculated afterwards got the wrong chord.

Same links as above. The build has been updated.

u/keyandcableco — 1 month ago
▲ 0 r/Synths4Sale

[WTS] Suzuki Omnichord OM-84 RESTORED -- No Reserve Auction -- $9.99 [L] GNV Florida

https://www.ebay.com/itm/198573710991

Auction starts tomorrow, Sunday August 16, 2026 at 6pm EST.

Glad to answer any questions! I work on these regularly, check my post history for more info. Happy bidding!

u/keyandcableco — 2 months ago
▲ 473 r/functionalprint

Battery Contact Spring Mandrel

https://www.thingiverse.com/thing:7389111

Currently setup for 0.8mm spring wire, SCAD file allows customization to your wire gauge. Print on its side at 100% infill with supports for maximum strength.

Put it in your drill, insert wire, bend 90 degrees, run the drill in reverse and wind slowly. Adjust the "pressure" you apply to the free end -- you don't want too much or the spring will be hard to remove. You may need to try a few times to get the hang of it.

Works great for old C-batteries, especially!

u/keyandcableco — 2 months ago
▲ 3 r/Omnichord

Hard-to-find Replacement Parts for OM-27, 36, and 84

Forgive me for shilling my wares, but you guys are about as niche as a community gets, so I want to make sure you get a link if these might help!

--------------------------
Sonic-Strings Dual-Concentric Potentiometer solution for OM-84

Sonic-Strings Dual-Concentric Potentiometer solution for OM-8

--------------------------

New Battery Spring PCBs for 27, 36, 84

https://preview.redd.it/unxia54g1mfh1.jpg?width=4624&format=pjpg&auto=webp&s=929825e57c287f43abbc0c78dcfd3e30c7062d1f

reddit.com
u/keyandcableco — 3 months ago
▲ 91 r/Omnichord

Fully-Serviced Suzuki Omnichord OM-84 for sale

Hi! I've got a few of these beauties ready for sale and I wanted to post here in case anyone is interested!

Recapped, refreshed, and has a polarity protection circuit so you won't ever fry it with the wrong power adapter, I hope this guy will hold value for a long time.

I hate where the market prices are for these things, but at least this one won't quit on you, and if it does, it has a technician standing behind it (me!)

ebay.io
u/keyandcableco — 3 months ago
▲ 8 r/Omnichord

If you could customize the Omnichord's strumplate, what would you want?

Different color options?

Tactile, raised "strings" or "bumps"?

Markers for every note?

A different note layout, perhaps?

More precise note presses?

Would you make it look more subtle by hiding the strum-strip? or make it super wide?

What's your experience? What do you wish the thing could do?

youtube.com
u/keyandcableco — 3 months ago
▲ 13 r/PCB

Am I looking at the ground/power plane eaten away on the inside? Salvageable?

This is a last-ditch effort to save a Peavey DPM 488 keyboard damaged by battery corrosion. I don't have tons of experience with anything more than a 2-layer board, so the lack of ground planes makes me think this is a 4-layer board, at least? And if that's the case, am I staring at holes eaten away in one of the planes?

u/keyandcableco — 3 months ago
▲ 9 r/Omnichord

OM-84 Replacement Strumpad Prototype

I need to sleep, but I'm too excited not to share this. Is this the first Omnichord Strumpad replacement? Just another step towards the OpenChord -- this is cheap and easily reproducible and works on original hardware.

Thank you for your interest, you can find more info here, and if you want a reproduction for your model, get in touch!

New Strumplate Demo

https://preview.redd.it/x753knzh35ah1.jpg?width=3472&format=pjpg&auto=webp&s=7c8b7f0eeaf2825686390976d53dddc4471f3b1c

reddit.com
u/keyandcableco — 4 months ago
▲ 24 r/Omnichord+1 crossposts

Towards an Open-Source, DIY Omnichord

I'm working on a project that involves replacing the brains of an OM-27 with a modern RP2350. Dubbed "The OpenChord Project" for now, it's only firmware that is meant to provide a core library for replacing other unobtainable/expensive chord logic chips and top-octave generators (TOG). There's another repo there that shows that the RP2350 can replace just the M083 as a TOG, really cool!

But what I really want to see is an Open Omnichord.The minichord is the best alternative I've seen otherwise, and Benjamin has done a lovely job providing support -- I honestly can't say enough good things about that project. I don't aim to outdo what he has done, I just want a version that is as analog as possible, and built with easily obtainable components, and easily printable/solderable for the average user.

I think the OpenChord firmware would likely be a good starting point for such a project. It would need some 3DP design ideas for the case, of course, and circuit boards designed around such a case (paging /u/JKTurtleSwag and /u/adamjsp). Power considerations, USB-C, etc. It's a solid project!

I've never really organized an open-source project, but they say if you love something, let it go. I'll probably mess about with some PCB designs over the coming months, we'll see what comes of it. Let me know what you think!

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u/keyandcableco — 4 months ago
▲ 24 r/Omnichord

Designing a new Strumplate -- also, there's a secret "reset" pad that's been hidden all along??

First of all, big thanks to u/adamjsp for sharing his scans of his broken strumplate. The man has just completed the only known repair of missing note traces on an OM-84 strumplate I have ever seen. I won't steal his thunder, but my jaw is agape at the results -- the stuff of legends. The silver paint is a lie, my whole life is a lie, they said it couldn't be done!

Anyway -- I think it's about time we have the option for a new strumplate for these older models. I've started an effort on GitHub and I'm interested in feedback and input from the community, especially if you have a broken plate you can scan for other models. I've got some untested Gerbers up, I think I'm ready to order, but this is my first flex PCB and I don't want to miss something silly. Might be interested in perhaps a CAD model that feels like the strumplate strings, maybe using conductive filament? The flex PCB itself is looking very promising and affordable, I'm very excited to test it!

ALSO -- We made an interesting discovery. There is an unused "reset" pad, fully wired up, but that is covered up by the topmost layer -- you can actually kind of feel that it's there above the original. The trace leads to an immediate dead end on the circuit board -- does anyone have any idea what this may have been intended as? This is probably still a usable trigger...

u/keyandcableco — 4 months ago