AMG Scale Controller
User Manual · v2.0

From download to first note

Five steps. Ten minutes. Then your phone tunes in quarter-tones and the Ribbon bends pitch on any keyboard that never had one.

Your setup

0 / 5

Tap a line to jump to it. Your ticks are remembered on this device.

Your device:
— the Install & Connect steps below follow your choice.
  1. A phone or tablet — Android 8.0+ or iPhone/iPad (iOS 17+). Nearly any device from the last several years.
  2. A way to connect it — a USB-OTG adapter on Android, or a USB-C cable / Lightning Camera Adapter on iPhone. This carries the MIDI. A few dollars.
  3. A supported instrument — one of the six families below.
  4. The app and your licence code — the download link and the code arrive by e-mail after your purchase.
Not sure your adapter works? Plug a USB keyboard into it first — if a key types, the port carries data, and it will carry MIDI too.

Supported families:

Korg KRONOS / X / 2 / 3

Full scale and transpose. The app spots a KRONOS on the cable and selects it for you.

Korg NAUTILUS

The default family. Auto-detected on connection.

Korg PA arranger series

Auto-detected, tuned to the PA line.

Korg M3

The M3 tunes note-by-note, so the app sends the scale cleanly when you lift your finger (see step 5).

Yamaha Montage / MOXF / XG

Montage, MOXF and XG-family instruments.

Software — MainStage & plugin instruments

Any app that accepts a standard tuning: one message sets the whole scale.

On Android the app is delivered directly (not through the Play Store yet), so Android asks your permission once before installing a file from outside the store. This is normal and expected.

  1. Download the file from the link in your e-mail. It is named AmgScaleController-v2.0-release.apk.
  2. Open it. Android will say it can’t install from this source yet, and offer a Settings button.
  3. Tap Settings → turn on Allow from this source (this permission belongs to your browser or Files app, not to us).
  4. Go back and tap Install. Takes a few seconds.
  5. Open AMG Scale from your app drawer.
Verify you got the real file (optional but wise). A genuine v2.0 release has this SHA-256 fingerprint:
2a37270e086320d66c2dbdf6a09e61b20ec169907559f0bfcb21a3def268b67d
Any file checker app can confirm it. If it doesn’t match, don’t install — write to us.
Updates. Every future version is signed with the same key, so a new .apk installs straight over the old one — your activation and settings stay put.

On iPhone & iPad the app is delivered through TestFlight, Apple’s official app for early releases. You’ll get an invite link together with your code.

  1. Install TestFlight (free, from Apple) from the App Store if you don’t have it yet.
  2. Open the invite link we e-mailed you → tap Accept.
  3. Tap Install on AMG Scale inside TestFlight. Takes a few seconds.
  4. Open AMG Scale from your home screen.
Updates. TestFlight tells you when a new build is ready — tap Update. Your activation and settings stay put.
iOS 17 or newer, iPhone or iPad. TestFlight is the clean way to reach early buyers before the App Store listing goes live — say “iOS” when you order and we send the invite.

On first launch the app shows an activation screen. It asks for two things:

  1. Your e-mail — the same address you used to buy.
  2. Your code — the one we sent back, shaped like AMG-XXXX-XXXX
  3. Tap Activate. The app quietly proves this phone to the licence server and unlocks. No password, nothing else to type.
Your licence, yours — the app makes a key on your phone that never leaves it, and ties your licence to it. That is why it then works fully offline, forever: no login, no subscription, nothing to check to play.

If activation is refused

MessageWhat it means · what to do
Unknown codeA typo, or the code isn’t live yet. Check for 0/O and 1/I — our codes never use those. Dashes and case don’t matter.
E-mail doesn’t matchUse the exact address the code was issued to.
All seats usedYour code has a set number of devices. Retiring an old phone? Write to us and we’ll free the seat.
Too many triesA safety pause after several failed attempts. Wait 15 minutes and try again.

Reinstalling on the same phone is free and automatic (a few times over) — the app recognises it and doesn’t spend a new seat.

📱
Phone / tablet
AMG Scale
OTG
🔌
USB-OTG
adapter
MIDI
🎹
Your instrument
  1. Plug the OTG adapter into the phone, then a USB cable from the adapter to your instrument’s USB / MIDI port. Power the instrument on.
  2. Android may ask “Open AMG Scale for this USB device?” — tap OK (tick “always” to skip it next time).
  3. The app lights its connection LED and, on Korg gear, auto-selects your family (KRONOS, NAUTILUS, PA…). You’ll see the slot light up.
  4. If it didn’t auto-detect, pick your family by hand from the slot selector — the same six from step 1.
Nothing lit up? It’s almost always the cable. Try a different OTG adapter or USB cable, make sure the instrument is on, and confirm the port on the keyboard is its MIDI/USB port and not a USB-storage-only socket. More in Help.
📱
iPhone / iPad
AMG Scale
USB-C / adapter
🔌
USB-C cable or
Camera Adapter
MIDI
🎹
Your instrument
  1. By cable (most reliable): a USB-C cable straight from a recent iPhone/iPad to the instrument’s USB port — or, on Lightning devices, Apple’s Lightning-to-USB Camera Adapter then a USB cable. Power the instrument on.
  2. iOS may ask to allow the accessory — tap Allow.
  3. Open AMG Scale. On Korg gear it auto-selects your family; otherwise choose your instrument in the MIDI destinations and your family from the slot selector.
  4. Or wireless: if your instrument speaks Bluetooth MIDI (directly, or via a WIDI / Yamaha MD-BT01 adapter), pair it in the app’s Bluetooth MIDI panel — no cable. Advanced setups can also use network MIDI (RTP) over Wi-Fi. (iOS has more connection routes than Android.)
Nothing lit up? Check the cable/adapter first, make sure the instrument is on and set to receive USB-MIDI, and that any Lightning Camera Adapter is genuine — cheap clones often fail. More in Help.

Tuning & quarter-tones

Pick a scale on the panel and the app tunes your instrument to it. Every note can move in quarter-tones — the notes between the notes — which is what maqam needs and a stock keyboard can’t reach.

The release rule — why nothing happens mid-slide

Drag a tuning and the panel follows your finger, but nothing reaches the instrument until you lift it. That way the change lands in one clean move, and your instrument is never left half-tuned.

Transpose held notes, cleanly

Change transpose while holding a chord and the app moves the sounding notes cleanly — nothing hangs. Let go, and everything stops as it should.

The Ribbon

The Ribbon replaces the pitch wheel — and gives one to instruments that never had it. Slide for a sustained glissando, lift to snap back to the anchor, hold the pedal to keep it. It’s the second reason this app exists.

On stage, it just plays. Once activated, the app never interrupts a performance to check a licence or reach the network. What’s tuned stays tuned.

The instrument doesn’t respond

In order of likelihood: (1) the cable or adapter — swap it, this is 90% of cases; (2) the instrument isn’t on the right USB / MIDI port; (3) the wrong family is selected — set it by hand; (4) on the instrument, make sure it’s set to receive MIDI on the right channel.

I reinstalled and it asks me to activate again

Deleting the app removes its on-phone key by design, so it re-activates on next launch. Enter the same e-mail and code — the same phone is recognised and doesn’t cost a new seat (a few reinstalls are free). Been through many? Write to us.

I bought a new phone

Your licence can be moved. Tell us your code and we’ll free the old seat so the new phone can activate.

“All seats used”

Each code covers a set number of devices — the anti-copy limit doing its job. Need more, or moving devices? We’ll sort it by e-mail.

Still stuck? Send us your code and a line about what you see. amg.scalecontroller@gmail.com