Karousel Rotary Drive User Manual
1Welcome
Thank you for choosing the Karousel Rotary Drive from Keystone Musical Instruments.
Karousel combines rotary speaker movement, cabinet character, drive, stereo depth and performance control in a compact pedal for guitar, bass, keyboards and studio use. From slow, vibey pulse to fast rotary shimmer, Karousel makes your tone move through space with musical realism and expressive control.
2Product Overview
- Rotary and drive pedal with Leslie-style cabinet modeling
- Variable horn and drum speed behavior
- Dual-speed rotary with speaker brake and acceleration control
- Vintage, Classic and Modern cabinet voicings
- Three selectable mic positions
- TRS input and output with selectable mono/stereo routing, set at startup or in Keystone Control Center
- APEX expression assignment for real-time control
- MIDI In/Thru and MIDI CC control
- 128 onboard presets
- Free lifetime firmware updates via USB
3Quick Start
- Connect your instrument or previous pedal to Karousel's TS/TRS input.
- Connect Karousel's TS/TRS output to your amp, pedalboard, mixer, interface or stereo breakout cable, as your audio mode requires.
- Set the mono/stereo mode (TS for mono; TRS for mono or stereo) with the startup configuration in section 4, or anytime in Keystone Control Center over micro-USB. Pro tip: rotary loves stereo.
- Connect a 9V DC center-negative regulated power supply.
- Press the right footswitch (Bypass) to engage Karousel.
- Use the left footswitch (Slow/Fast) to change rotor speed. Press and hold it to brake the rotor.
4Mono and Stereo Operation
Karousel has one TRS input jack and one TRS output jack. Routing is set at startup and can also be changed in Keystone Control Center. Always check the routing mode before troubleshooting stereo behavior, and use the right TS, TRS or breakout cables for your rig.
| Mode | Cabling | When to use it |
|---|---|---|
| Mono in / mono out | Standard mono connections, with the TRS jacks working in mono mode. | A traditional single-instrument, single-amp pedalboard. |
| Mono in / stereo out | A mono source in, then the TRS output to a stereo breakout or TRS stereo destination. | A spacious stereo rotary image from a mono instrument. |
| Stereo in / stereo out | TRS stereo cables or suitable breakouts into the input and out of the output. | A stereo pedalboard, keyboard rig, studio chain or effects loop. |
Set the mode
- Disconnect power from Karousel.
- Connect the cables for your rig: standard mono cables for mono, or TRS stereo/breakout cables for stereo.
- Press and hold the startup configuration footswitches.
- Reconnect power, holding the footswitches until Karousel enters configuration mode.
- Select mono in/mono out, mono in/stereo out, or stereo in/stereo out.
- Confirm the selection and restart the pedal if prompted.
- Play through your rig and check that the signal reaches the expected mono or stereo destination.
You can also change routing in Keystone Control Center: connect Karousel over micro-USB, open the app, select the pedal and choose the routing mode.
5Controls
| Control | Function |
|---|---|
| SlowPOT 1 · Slow Speed | Slow rotor rate, from a deep, unhurried 0.1 Hz pulse to a lively 4 Hz swirl. For gentle movement, slow speaker bloom and expressive background motion. |
| FastPOT 2 · Fast Speed | Fast rotor rate, 4 Hz to 10 Hz. Lower gives classic cabinet acceleration; higher gives a more urgent shimmer. |
| Drum:HornPOT 3 | The relationship between the virtual drum and horn speeds. Lower keeps them closely locked; higher separates them for a wobblier feel. |
| DrivePOT 4 | Post-effect clean-ish boost/cut. Down for a cleaner cabinet; up to amplify what the rotor is doing, with a little added grit. |
| IntensityPOT 5 | Tremolo depth, from subtle movement to full, pulsing amplitude modulation. |
| DepthPOT 6 · Doppler | The pitch-motion part of the rotary effect, 0.3 ms to 0.7 ms. Lower feels tighter and more focused; higher gives more pronounced Doppler movement toward and away from the mics. |
| AccelerationSWITCH 1 | How quickly Karousel moves between slow and fast: Slow for a gradual ramp, Medium for a balanced transition, Fast for near-instant changes. |
| CabinetSWITCH 2 | Tonal center of the virtual cabinet: Vintage (500 Hz) for a darker, worn-in voice, Classic (800 Hz) for balanced character, or Modern (1200 Hz) for a brighter, more forward response. |
| Mic PositionSWITCH 3 | Mics at the front, rear or both. Front or rear alone gives a more pronounced Doppler effect than both. |
6Footswitches and Indicators
- Right footswitch, Bypass: turns Karousel on or off.
- Left footswitch, Slow/Fast/Brake: tap to toggle between the Slow and Fast speeds, following the Acceleration setting. Press and hold to brake: the horn and drum slow toward a stop for dramatic pauses, transitions and organ-style gestures.
- RGB indicators: confirm bypass, speed state, preset status and performance mode at a glance.
7Suggested Sounds
| Sound | Starting point |
|---|---|
| Classic B3 organ | Cabinet on Vintage, Slow at 2 Hz, Fast at 6 Hz, Intensity at 50% and Drive at 30%. |
| Psychedelic swirl | Cabinet on Modern, Slow at 1 Hz, Fast at 8 Hz, Intensity at 80% and Depth at 0.7 ms for a pronounced Doppler effect. |
| Gritty blues rock | Cabinet on Classic, Slow at 3 Hz, Fast at 7 Hz, Drive at 75% for extra grit, and Acceleration on Fast. |
| Ambient shimmer | Cabinet on Modern, Slow at 0.5 Hz, Fast at 5 Hz, Intensity at 40% and Depth at 0.4 ms for subtle, spacious movement. |
8APEX Expression Control
APEX (Assignable Programmable Expression) is Keystone's expression-control system. Once assigned, the expression pedal sweeps any or all chosen parameters in real time, over the full range or part of it, normal or inverse, so you can build complex, unique expressions. Combined with slow/fast/brake, it turns Karousel from a set-and-forget rotary tone into a dynamic, foot-on performance instrument.
- Unplug 9V power.
- Hold FS1 (right footswitch) while you plug power back in.
- LED 1 (the left LED) blinks rapidly to confirm Karousel is in expression setting mode.
- You can assign any or all knobs to the expression pedal, over the full range or part of it, with direct or inverse mapping.
- To assign a knob's full sweep, turn it in the direction you want it mapped: up for up, down for down.
- To set a range instead, hold FS2 (left footswitch) while turning the knob to set two points, a minimum and a maximum.
- Karousel confirms each point with two blinks. Set the first value, wait for the blinks, then set the second.
- For direct mapping, set the minimum first, then the maximum. For inverse mapping, set the maximum first, then the minimum.
- After both values are confirmed, release FS2.
- To clear all assignments, flip SWITCH 1 (left). To clear only the most recent one, flip SWITCH 2.
- Press FS1 to exit. The LED blinks once for each parameter linked to the expression pedal.
- APEX settings stay on the pedal and can be backed up with Keystone Control Center.
9Keystone Control Center
Keystone Control Center is the free Mac and Windows companion app for Keystone pedals. Connect over micro-USB to set the audio routing mode, manage presets and device settings, back up APEX assignments and install free lifetime firmware updates. When you move between mono pedalboards, mono-to-stereo rigs, keyboard setups, studio interfaces and stereo amp systems, it's the clearest way to check and save the active routing. Download it at keystonemusical.com/pages/keystone-control-center.
10MIDI, Presets and Firmware
Karousel has MIDI In/Thru and MIDI CC control for switchers, controllers, studio rigs and preset-based workflows. Its 128 presets save rotor speeds, cabinet type, mic position, drive, intensity, Doppler depth, acceleration, APEX assignments, audio routing and other performance settings. Firmware updates are free for life and install over micro-USB with Keystone Control Center.
Karousel uses the MIDI Type-A TRS standard for MIDI In and MIDI Thru. MIDI Thru repeats everything arriving at MIDI In, so one connection on the first pedal can carry tempo, CC and PC messages down the whole board over inexpensive TRS cables instead of bulkier 5-pin MIDI cables.
11MIDI CC Mappings
Continuous parameters
| CC | Parameter | Pot | Range |
|---|---|---|---|
| 50 | Slow Speed | POT 1 | 0.1 Hz – 4 Hz |
| 51 | Fast Speed | POT 2 | 4 Hz – 10 Hz |
| 52 | Drift (Drum:Horn) | POT 3 | 0–100% |
| 53 | Drive Amount | POT 4 | 0–100% |
| 54 | Intensity | POT 5 | 0–100% |
| 55 | Doppler Depth | POT 6 | 0.3 ms – 0.7 ms |
Three-position switches
| CC | Parameter | Position 1 (0–42) | Position 2 (43–84) | Position 3 (85–127) |
|---|---|---|---|---|
| 56 | AccelerationSWITCH 1 | Slow | Medium | Fast |
| 57 | Cabinet TypeSWITCH 2 | Vintage (500 Hz) | Classic (800 Hz) | Modern (1200 Hz) |
| 58 | Mic PlacementSWITCH 3 | Near | Mid | Far |
The left footswitch's speed toggle (tap) and brake (hold) aren't CC-controlled.
12LED Color Standards
Karousel's signature color is purple . Universal colors are the same on every Keystone pedal and mark configuration modes and special states.
| State | Color | When used |
|---|---|---|
| I/O Mode Config | White | Boot mode: selecting audio routing |
| APEX Mode | Magenta | Boot mode: expression pedal assignment |
| MIDI Sync | Bright green-cyan | Synced to MIDI clock |
| Tap Tempo | Cyan | Tap tempo learning mode |
| Save Confirm | Bright green | Settings saved successfully |
| Clear/Delete | Amber | Clearing assignments or settings |
13Troubleshooting
| Problem | Try this |
|---|---|
| No sound | Check the input, output, amp or interface, bypass status, preset level and power supply. |
| Wrong mono/stereo behavior | Restart Karousel and select the audio mode at startup, or change the routing in Keystone Control Center. |
| No stereo image | Make sure Karousel is set to the intended stereo mode, then check that the TRS output, stereo destination or breakout cable is wired correctly. |
| Expression pedal doesn't respond | Use a compatible expression pedal and cable, reconnect it, then reassign the parameter in APEX mode. |
| APEX range feels reversed | Relearn the assignment with heel and toe values reversed (set the maximum first for inverse mapping). |
| MIDI control doesn't respond | Check the MIDI channel, cable direction, controller mapping and CC numbers (listed in section 11 and in Keystone Control Center). |
| Firmware update fails | Restart the update, try a known-good micro-USB cable, and make sure the updater and firmware files come from Keystone Musical Instruments. |
14Specifications
| Product | Karousel Rotary Drive |
| Firmware | 1.4 |
| Effect type | Rotary speaker with drive |
| Cabinet models | Vintage, Classic, Modern |
| Mic placement | Front, rear, both |
| Slow speed | About 0.1 Hz to 4 Hz |
| Fast speed | About 4 Hz to 10 Hz |
| Audio | 24-bit / 96 kHz processing; one TS/TRS input and one TS/TRS output for mono or stereo operation |
| Audio routing | Set at startup or in Keystone Control Center; use TRS for stereo or mono, TS for mono only |
| Bypass | Buffered (ideal for time-based effects) |
| MIDI | Type-A TRS In and Thru; CC control; USB MIDI |
| Presets | 128 onboard presets, including APEX settings |
| Expression | APEX expression control |
| Firmware updates | Free for life via micro-USB |
| Power | 9V DC center-negative regulated supply |
| Warranty | One year from the original purchase date |
15Care and Safety
- Use only the recommended power supply.
- Keep the pedal dry and away from extreme heat, cold, dust and moisture.
- Disconnect power and cables before cleaning.
- Clean the enclosure with a dry, soft cloth. Don't use solvents or abrasive cleaners.
- Don't open the enclosure unless instructed by qualified service personnel.
16Warranty and Support
Keystone Musical Instruments warrants the Karousel Rotary Drive against defects in materials and workmanship for one year from the original purchase date. The warranty doesn't cover damage from misuse, unauthorized modification, accident, improper power supply, liquid exposure or normal wear. For service, registration, firmware updates and support documents, visit keystonemusical.com.
