Rubigo RB3 — User Manual

1. Introduction

Rubigo RB3 is a software emulation of the Hammond B3 tonewheel organ. It models three manuals' worth of drawbars (Upper, Lower, Pedals), the mechanical key click of real contact bars, the vibrato/chorus scanner, percussion, a physically modeled rotary speaker cabinet, a spring reverb, and an amp + cabinet output stage with neural-modeled guitar amps for a completely different, driven tone.

It's available as a CLAP and VST3 plugin for Linux, Windows and macOS.

About the Hammond B3

The real Hammond B3 (built 1954–1974) generates its sound electromechanically: 91 metal tonewheels, spinning on 12 motor-driven shafts, each pass a magnetic pickup and induce a tiny AC signal — no digital synthesis, no samples, just spinning metal and magnets. It's fully polyphonic with no voice stealing, and it has no velocity sensitivity or aftertouch at all — every key produces exactly the same volume no matter how hard you hit it. Dynamics come entirely from the Swell pedal.

Signal chain

From a held key to the speakers, the signal passes through, in order:

1. Tonewheel generator — one waveform per drawbar per note, with crosstalk and leakage already baked in (see Why It Sounds Authentic)
2. Key click & percussion — contact noise at note-on/off, plus the optional percussive harmonic transient
3. Drawbar mixing — the 9 (or 2, for Pedals) drawbars for that manual are summed according to their positions
4. Vibrato/chorus scanner — if enabled for that manual
5. Manuals combine, then go through the Swell pedal — modeled on the organ's real expression control, so closing it also changes the tone and cleans up the drive, as on the original
6. Spring reverb — by default here, before the amp and the rotary speaker, so they shape the reverb too (Reverb Position)
7. Output stage — Rotary, Amp + Cabinet, or Direct (pick one, see Amp, Cabinet & Output Mode)
8. Spring reverb — here instead when Reverb Position is After Rotary
9. Master Volume — final output level

2. Quick Start

1. Install RB3 (see Installation) and load it on a track in your DAW, or run it standalone.
2. Route a MIDI keyboard to it. By default the Upper manual listens on MIDI channel 1, Lower on channel 2, and Pedals on channel 3 (SETTINGS → MIDI, if you need to change them) — if you're playing from a single regular keyboard with no channel-splitting, you'll want it sending on channel 1 to reach the Upper manual.
3. Play a few notes — RB3 starts on its Default preset, a jazz registration (788400000) with percussion, C3 chorus and the rotary speaker on Slow, so it sounds like a B3 straight away.
4. Pull out a couple more drawbars, or pick another preset from the selector in the top bar (try Full Organ or Rock).
5. Flip the rotary switch to Fast and back to Slow to hear the rotary speed change — this is the single most "B3" thing you can do.
6. Explore SETTINGS → FX to try Amp + Cabinet mode for a completely different, driven electric-guitar-amp tone instead of the rotary speaker.

3. Installation

Linux

Rescan plugins in your DAW afterwards if it doesn't pick the new file up automatically.

Windows

%COMMONPROGRAMFILES% is normally C:\Program Files\Common Files (not the Program Files (x86) one — RB3 is 64-bit only). Copying there needs administrator rights. Rescan plugins in your DAW afterwards.

Requires a 64-bit CPU with AVX2 (any CPU from roughly 2013 onward).

macOS

The macOS download is universal (Apple Silicon and Intel) and needs macOS 11 or later. Each format comes as a zip; Safari unzips it for you.

macOS quarantines downloaded plugins that aren't notarized by Apple, and DAWs won't load them. Allow RB3 once by pasting this into Terminal, then rescan plugins in your DAW:

xattr -dr com.apple.quarantine ~/Library/Audio/Plug-Ins/VST3/Rubigo_RB3.vst3 ~/Library/Audio/Plug-Ins/CLAP/Rubigo_RB3.clap

On an Intel Mac, the CPU needs AVX2 (Macs from roughly 2013 onward).

The plugin's custom interface requires a graphics driver capable of OpenGL 3.x (the GUI renderer needs it; audio/DSP itself does not). RB3 checks for this automatically at load time — on a system without it, the plugin still loads and plays normally, it just runs without its custom window, and is controlled through your host's generic parameter list instead. This is most likely to come up in a virtual machine or on a minimal/headless Linux audio server with only a software (non-GPU) display driver. See Troubleshooting if you expected a window and don't see one.

4. Licensing & Activation

Linux

Rubigo RB3 is completely free on Linux — no license key, no trial countdown, no registration screen. Install it and play.

The first time you open it, RB3 asks once whether you'd like to be counted as a Linux user. Yes sends a single anonymous message (a random number, "linux" and the version, nothing about you or your computer); No sends nothing. Either way it never asks again.

Windows and macOS

On Windows and macOS, open SETTINGS → License in the plugin. The price and the trial are the same on both. From there you can:

• Start a 30-Day Trial — one click, no account required, fully working for 30 days.
• Activate — paste the license key you received after purchase into the field (there's a dedicated Paste button next to it, since some hosts don't give the plugin window keyboard focus) and click Activate.
• Buy Now — opens the Rubigo Audio store in your browser.

Your license is tied to the specific computer you activate it on. If you need to move it to a new machine, get in touch (see Support) and we'll sort it out.

If your trial or license lapses, RB3 keeps running, but the rotary/vibrato modulation will audibly drift out of tune within about half a minute of playback as a reminder. Reactivating fixes it immediately — no plugin or DAW restart needed.

5. Interface Overview

The top bar is present on every screen:

• CONSOLE / CONTROL / SETTINGS — the three main tabs (see below).
• Preset selector — shows the current full-organ preset; step through with the ◄/► arrows or click the name to open the full list.
• "?" button — opens this manual in your browser.

CONSOLE

The full vintage console view, including a playable two-manual keyboard and pedalboard — useful when you want to audition sounds with the mouse, or just enjoy the look of the thing. All drawbars, the vibrato/chorus selector, percussion switches, master/key-click/overdrive/reverb knobs, the rotary brake/fast slider and the swell pedal are all here.

CONTROL

The same core controls as CONSOLE, laid out larger and without the keyboard — easier to operate precisely with a mouse, and it also shows the per-manual quick registrations (see Drawbars & Presets).

SETTINGS

Seven sub-tabs along the second row, covering everything that isn't a front-panel control. Settings Reference shows each page and explains every control on it.

Settings with a few fixed choices (Organ Character, Drive Mode, Output, Amp Model, Cabinet, Cabinet Type, Mic Setup, Amp Type) use a vertical selector: click a choice's name, or its position on the selector, to pick it, or press on it and drag up or down to move through the choices. A block that doesn't apply to the current Output is dimmed and can't be changed.

6. Drawbars & Presets

Each manual has 9 drawbars, named by their pipe footage — the traditional way of describing a tonewheel's pitch relative to the fundamental:

The Pedals manual has two drawbars (16' and 8'). Click and drag a drawbar to set its level from 0 (fully in) to 8 (fully out). If you'd rather drag the other direction, flip Reverse Drawbars in SETTINGS → MIDI.

A freshly-loaded RB3 plays the Default preset: Upper 788400000, Lower 808000000, Pedals 16' at 6 and 8' at 3, percussion on (soft, fast, 3rd), C3 chorus on the Upper manual and the rotary speaker on Slow.

Full-organ presets

The preset selector in the top bar holds 10 factory presets — Default, Jazz, Full Organ, Rock, Ballad, Blues, Reggae, Soul/R&B, Gospel and Whistle — and up to 10 of your own. Step through them with the arrows or pick one from the list. Once you change any of the settings a preset made, the selector shows its name with (modified), so you still see where you started; Custom means the settings didn't come from a preset.

A preset sets the whole sound: every setting except the MIDI setup (channels, CC assignments, rotary switch mapping), Reverse Drawbars and Master Volume. So a preset always sounds the same, whatever you changed before. The factory presets differ in the settings below; everything else is as in Default. Drawbars are in notation order (16' to 1').

Saving your own presets

When the selector shows (modified) or Custom, it also shows a save button. Click it, type a name and press OK (or Enter). Your preset appears in the list below the factory presets, after a divider, and the selector moves to it. Saved presets are shared by every instance of RB3, in any DAW on this computer: a preset saved in one instance appears in the others' lists straight away.

A saved preset stores the whole sound, like the factory presets (everything except the MIDI setup, Reverse Drawbars and Master Volume). Presets saved with versions before 1.3 stored only drawbars, percussion, vibrato/chorus, rotary speed, drive and reverb; they now play those over the Default sound. To update one of your presets, change it and click save: the dialog starts with its name, and OK replaces it. Names of factory presets and of your other presets are refused, so nothing is overwritten by accident.

There are 10 slots for your own presets, numbered 1–10 in the list's custom section. When all 10 are in use, the save dialog asks which one to replace: pick it and press OK, or Cancel to keep them all.

The presets are kept in one file, Rubigo/RB3/user_presets.json in your user configuration folder (~/.config on Linux, ~/Library/Application Support on macOS, %APPDATA% on Windows). Copy it to take your presets to another computer.

Switching presets from MIDI or automation

Each preset has its own MIDI CC: CC 81–90 for factory presets 1–10 and CC 103–112 for your presets 1–10. A value of 64 or more selects the preset (a button press, or a CC sent from your DAW at value 127); lower values, such as a button's release, do nothing. Sending it again re-selects the preset and undoes any changes. You can change the CCs in SETTINGS → PRESETS, which lists all 20 presets with their CC and a Learn button.

RB3 also responds to Program Change on any MIDI channel: Program Change 1–10 selects the factory presets and 11–20 your own, which is what many keyboards' preset buttons send.

These CCs and Program Changes are recorded in your track's MIDI part like any other controller move, so they play back with the song without any automation setup.

Picking a preset with the mouse sets RB3's Preset parameter instead (0 = none, 1–10 factory, 11–20 your own). Your DAW records it only when the track's automation is in a recording mode (Write, Touch or Latch in REAPER); the Preset lane then shows preset names and plays the changes back. Projects save a copy of your presets, so a song replays with the same sounds on a computer that doesn't have them.

Per-manual quick registrations

On the CONTROL screen, each manual has its own row of quick-recall buttons for classic named Hammond registrations — Stopped Flute, Dulciana, French Horn, Salicional, Flutes 8'+4', Oboe, Swell Diapason, Trumpet, and Full Swell — plus a blank button that's highlighted whenever the manual's drawbars don't match any of them. These apply independently to the Upper and Lower manual.

Reading traditional drawbar notation

Hammond players traditionally write a registration as nine digits, one per drawbar in order (16', 5⅓', 8', 4', 2⅔', 2', 1⅗', 1⅓', 1'), each 0–8. You'll see these numbers on setlists, tutorials, and forums everywhere — they translate directly to drawbar positions in RB3:

7. Percussion

Percussion adds a decaying extra harmonic — a short, bell-like transient — triggered only on the first note of a new phrase. It's monophonic (one voice, like the real circuit) and only re-triggers once every key on the manual has been released and a new one is pressed — hold a chord and add notes on top and you won't hear it again until you let go completely. Four switches control it, found on CONSOLE, CONTROL, and — for the underlying parameters — SETTINGS:

Percussion is a classic Hammond combo organ effect — it's meant for single-note or thin-chord lead lines (think jazz comping), not for pads with percussion left on underneath a full registration, where the transient tends to just add clutter.

8. Vibrato & Chorus

On a real B3, this effect comes from a mechanical "scanner" that sweeps a phase-shifted copy of the signal across a set of taps — not a pitch LFO. RB3's implementation follows the same phase-shifting principle rather than simply wobbling pitch, which is why it stays clean and doesn't smear the tone the way a generic chorus pedal would.

The selector offers six positions — V1, V2, V3 (vibrato only, increasing depth) and C1, C2, C3 (the vibrato signal blended back with the dry signal for a thicker, chorus-like effect, also increasing depth). It can be enabled independently for the Upper and Lower manual via the UPPER/LOWER switches next to the selector. The Pedals follow the LOWER switch, as on the real instrument, where the lower manual's output circuit also serves the pedal keyboard.

A quick way to pick a setting: V1 for a subtle, controlled shimmer that won't fight with a busy mix; C3 for the thick, unmistakably "Hammond" swirl heard on ballads and gospel playing.

9. Rotary Speaker

The rotary speaker — best known as the Leslie cabinet — was never part of the Hammond B3 itself; it's a separate cabinet — but the two are inseparable in practice, and it's most of what makes a B3 sound like a B3. Physically it has two independent rotors spinning at different rates: a treble horn up top and a bass drum below, each producing Doppler pitch shift and amplitude modulation as they spin toward and away from a pair of microphones.

The front-panel switch cycles between Brake (rotors stopped), Slow ("chorale"), and Fast ("tremolo"). How the rotary speed CC (CC 1 by default) maps to them is set in SETTINGS → MIDI → Rotary Speed: Slow - Brake - Fast or Brake - Slow - Fast (the default) for a 3-way switch or lever, or Toggle for a momentary footswitch such as a sustain pedal, where each press flips between Slow and Fast. Switching speed doesn't jump instantly: the horn and drum each ramp to their new speed over their own acceleration time, which is where a lot of the classic "spin-up" swirl comes from.

SETTINGS → Rotary exposes the full physical model:

Cabinet Type picks the cabinet: 122 / 147 (the classic two-speed cabinets), Studio 12 or G37. Each is modeled on measurements of that cabinet — horn compartment, drum, crossover, tone and decay. Brightness tilts the horn's treble (a shelf around 3 kHz); its range covers the difference in treble measured between real cabinets, and 0 dB is the modeled cabinet as it is. Beam Focus narrows or widens the horn's directional "beaminess"; Horn Radius is the horn's effective size, which sets how much Doppler pitch shift it makes. Turbulence adds the faint air/mechanical rumble of the rotors moving. Acceleration is the spin-up time; slowing down takes a little longer, as on the real cabinet.

Mic Setup picks a microphone placement. Custom uses the Mic Distance and Angle Between Mics controls (closer in emphasizes more tremolo/Doppler movement, farther out blends more of the room). These two controls only act in Custom: with another setup they are greyed out, and clicking one switches back to Custom. The other setups are fixed placements: Classic 122 (two horn mics on opposite sides, one drum mic in front), Front Pair (a stereo pair 60 cm in front, 60° apart), Mono 1 m (one mic 1 m in front) and Room (a pair 2 m away with floor, ceiling and back-wall reflections). To play without the rotary speaker, set SETTINGS → FX → Output to Direct Output or Amp + Cabinet.

Power Amp → Amp Type picks what drives the rotary speaker: the 122 cabinet's own tube amp or one of three overdrives (see Power Amp types). The whole Rotary page only applies when SETTINGS → FX → Signal Path → Output is Rotary; with another Output it is dimmed and locked, and a note at the top says so.

10. Amp, Cabinet & Output Mode

SETTINGS → FX controls what happens after the organ signal leaves the tonewheels. Its Signal Path block holds the drive and the Output selector (Rotary, Amp + Cabinet, Direct Output):

The guitar amp and cabinet are chosen in the Amp + Cabinet block (Amp Model, Cabinet), which is only active in Amp + Cabinet mode: in the other modes the whole block is dimmed and can't be changed. Likewise the whole SETTINGS → ROTARY page (rotary speaker and Power Amp) only acts in Rotary mode: in the other modes it is dimmed and locked, with a note at the top.

Power Amp types (Rotary mode)

What drives the rotary speaker, chosen with Amp Type in the Power Amp block of SETTINGS → ROTARY. Modern stage organs offer several overdrive types ahead of their rotary speaker; RB3 does the same, with Drive setting how hard each one is pushed:

The three overdrive choices add the bright, gritty upper-mid edge heard on modern organs at full overdrive, which the 122's tube amp alone doesn't produce. Switching between them is click-free, with a brief silent gap while the new model settles.

Guitar amps (Amp + Cabinet mode)

Four neural-modeled amps, each with its own Drive response, chosen for how organ has been played through guitar amps:

Cabinets

Seven cabinet impulse responses, paired with any amp model:

Reverb

A spring reverb model, six controls:

Before Rotary puts the spring after the swell pedal and before the amp and the rotary speaker: the reverb is driven through the amp and spun by the rotors, as when a spring sits between the organ and its speaker cabinet. After Rotary adds it at the very end, in stereo, over the finished sound.

11. Tonewheel Character & Key Click

SETTINGS → Tonewheel covers the character of the tonewheel generator itself:

Organ Character models how real organs differ from one another, using measurements of several recorded organs: Typical is the middle of them; Clean has the least second harmonic, wheel-to-wheel unevenness and bleed measured; Worn / Bright the most; Leaky / Humming has strong bleed and the hum of the hummiest organ measured (60 Hz mains); European 50 Hz follows the measured European organ, with 50 Hz mains hum. The hum only sounds when Mains Hum is turned up.

Click Level defaults to 60%, a little over the full click of a real key contact (50%). Real Hammonds vary a lot in how much click they have depending on age and maintenance, so dial in as much (or as little) mechanical grit as you want: 0% for a smooth onset, up to 100% for an exaggerated click.

Why It Sounds Authentic

A real Hammond's imperfections were mechanical, not random — a given tonewheel's wobble, a gear's tooth irregularities, a pickup's quirks were fixed physical properties that repeated identically on every rotation. RB3 models that directly: those imperfections are baked into the tonewheel waveforms themselves rather than added as runtime randomness, which is closer to how the real instrument actually behaved.

A few specific things this buys you:

• The "zipping" attack. On a real B3, the nine busbar contacts under a key close in sequence as the key travels down (highest harmonics first), not all at once. RB3 models that staggered contact closure, so chords have the same slightly textured attack a real console does instead of a synthetic, perfectly simultaneous one.
• Tonewheel crosstalk. On the real instrument, the turning tonewheels bleed faintly into each other's signals. RB3 reproduces the bleed measured in real organs: every note you play also sounds faint copies of the wheels that leak into it, each at its own pitch and measured level (the Crossleak control in SETTINGS → Tonewheel), rather than treating each note as a perfectly isolated oscillator.
• Motor hum leakage. The real B3's drive motor and power supply leak a faint, constant hum into the signal — present even when no keys are held. RB3 reproduces it (the Leakage control, same screen). It is off by default, like the rotary's air noise (Turbulence) and Mains Hum, so a fresh RB3 adds no noise to your recordings until you ask for it.

12. MIDI

Each manual (Upper, Lower, Pedals) listens on its own configurable MIDI channel, set in SETTINGS → MIDI:

If you're playing from one regular keyboard with no way to split MIDI channels, leave everything on channel 1 and set both Lower Manual and Pedals to channel 1 too, in SETTINGS → MIDI — all three manuals can share a channel if that's simpler for your setup.

Every CC mapping row there has two ways to change it: type a CC number directly into the box, or click Learn and then move a control on your MIDI keyboard/controller — RB3 captures the CC number automatically.

Below the Upper and Lower Manual mappings, the Drawbars block holds Reverse Drawbars, which flips the direction a drawbar is dragged (see Drawbars & Presets).

Factory default CC assignments:

Every one of these is a factory default, not a fixed assignment — remap anything to suit your controller.

13. Settings Reference

Every page under SETTINGS, block by block in the order they appear on screen. The topic chapters explain the background (how a rotary speaker works, what tonewheel leakage is); this chapter is the place to look up a single control.

Knobs on the settings pages show their position as a percentage of their range. The tables give the real values: Horn Slow Speed at 0.80 Hz, for example, shows as 37%. Your DAW's parameter list shows the real values too.

Tonewheel

The tonewheel generator itself: how clean or worn it sounds, how keys click, and the overall level. Background: Tonewheel Character & Key Click.

Tonewheel Character

Organ Character

Key Click

Output

FX

Drive, the output path, the guitar amp and cabinet, and the reverb. Background: Amp, Cabinet & Output Mode.

Signal Path

Reverb

A spring reverb, after the rotary speaker or amp.

Amp + Cabinet

Active only with Output on Amp + Cabinet; otherwise dimmed and locked.

Rotary

The rotary speaker and the amp that drives it. The whole page acts only with SETTINGS → FX → Output on Rotary; otherwise it is dimmed and locked, and a note at the top says so. Background: Rotary Speaker.

Horn

Drum

Cabinet

Power Amp

Microphones

With another setup than Custom, Mic Distance and Angle Between Mics are greyed out; clicking one of them switches back to Custom.

MIDI

Which MIDI controller moves which control, and which channel each manual plays on. The MIDI setup is saved with your project and is not part of presets. Background: MIDI.

Upper Manual, Lower Manual, Pedals and FX

Each row is one control with its CC number and a Learn button. Defaults: upper drawbars CC 12–20, lower drawbars CC 21–29, pedal drawbars CC 30–31; Swell CC 11, Drive CC 70, Vibrato (the V1 … C3 selector) CC 33, Vib Upper (the Upper vibrato on/off switch, 64 or more = on) CC 102, Master (volume) CC 7.

• Type a number into the box to assign that CC; −1 unassigns the control. Typing doesn't take the CC away from another control, so check no other row uses it: if two controls share a CC, only the first in the list responds.
• Learn opens the MIDI Learn dialog (below) and takes the CC away from any other control.

MIDI Channel

Rotary Speed

Drawbars

The MIDI Learn dialog

1. Click Learn on a row. Its button turns red and the dialog opens.
2. Move the knob, slider or button on your controller. Last CC shows the controller number received; move another one to change it.
3. Click Apply to assign it, or Cancel to keep the old one.

When learning a manual's first drawbar (16'), tick use consecutive CCs for the other bars to assign the remaining drawbars of that manual to the following CC numbers in one go: learn CC 40 on Upper 16' and the other eight get CC 41–48. Any other control on those CCs is unassigned.

Presets

All 20 presets, each with the MIDI CC that recalls it and a Learn button, which work as on the MIDI page. A CC value of 64 or more selects the preset; sending it again undoes any changes. Defaults: factory presets 1–10 CC 81–90, custom presets 1–10 CC 103–112. Program Change 1–10 selects the factory presets and 11–20 the custom ones. The custom list shows the names of the presets you have saved, or (empty). See Drawbars & Presets.

Saving a preset

When the preset selector at the top shows (modified) or Custom, it has a save button. Click it, type a name and press OK (or Enter). Saved presets are available in every instance of RB3 on this computer. Details, including updating and replacing presets: Saving your own presets.

License

More: Licensing & Activation.

Support

14. Troubleshooting

Percussion doesn't seem to do anything

• Percussion is monophonic and only triggers on the first note after every key on the manual is released — it won't re-fire on each note of a held chord.
• It's most audible on the higher registers with the 2' or 1' drawbars present; on a bass-heavy registration with no top-end drawbars, the extra harmonic can be hard to hear.

No sound

• Check the manual you're playing on (Upper/Lower/Pedals) is set to the MIDI channel your controller is actually sending on (SETTINGS → MIDI).
• Check at least one drawbar on that manual is pulled out above 0.
• Check Master Volume (SETTINGS → Tonewheel) isn't at the bottom.
• Check your DAW is routing the track's output somewhere audible.

The Rotary page (or the Amp + Cabinet block) is greyed out

• They only apply to one signal path. Choose it with SETTINGS → FX → Signal Path → Output: Rotary for the Rotary page, Amp + Cabinet for the Amp + Cabinet block.

Plugin doesn't appear in your DAW

• Double check the install path for your platform and format (see Installation).
• Rescan plugins — most DAWs cache their plugin list and won't pick up a new file automatically.

Plugin loads and plays, but no custom window/GUI appears

RB3's custom interface requires OpenGL 3.x, checked automatically each time the plugin loads. If your system's graphics driver can't provide that — common in a VM without GPU passthrough, remote desktop sessions, or a minimal audio server — RB3 falls back to running headless: audio processing is unaffected, but there's no custom window, and you control it through your host's generic parameter list instead. This is expected behavior, not a crash. If you expected a GPU to be available, check your VM's 3D acceleration/GPU passthrough settings, or (Linux) run glxinfo -B to see what your system currently reports.

DAW crashes on startup or when loading a project (Linux)

If this happens specifically while restoring a project with several plugin GUIs open at once (RB3 and/or others), it's very likely GPU/GLX resource contention — common in virtualized environments or on GPUs with limited video memory — rather than a plugin bug. Try starting your DAW with a blank project and inserting RB3 fresh, or launch your DAW with LIBGL_ALWAYS_SOFTWARE=1 set to force software rendering.

15. FAQ

Why doesn't hitting the keys harder make it louder?

Neither did the real B3. It has no velocity sensitivity or aftertouch — dynamics are entirely a function of the Swell pedal, exactly like the original instrument. This is a deliberate design choice, not a limitation.

Can I save my own presets?

Yes. Click save in the preset selector when it shows (modified) or Custom, and name the preset; it's then available in every instance of RB3 (see Saving your own presets). Your DAW's project save also keeps whatever you've dialed in, the same as any other plugin's state.

What's the difference between CONSOLE and CONTROL?

Same controls, different layout. CONSOLE includes the on-screen keyboard and looks like the real cabinet; CONTROL is bigger and easier to operate precisely with a mouse, and adds the per-manual quick registrations. Neither one is more "authoritative" than the other — they're both just views onto the same parameters.

Does Amp + Cabinet mode replace the rotary speaker sound?

Yes, for as long as it's selected — output mode is one-or-the-other, not stacked. Switch back to Rotary mode to get the rotary speaker sound back; switching between modes crossfades rather than cutting abruptly.

Why is there no velocity, but there's a Drive/overdrive knob?

Drive sets how hard the organ pushes the amp — on a real organ that is set once by the technician — while the Swell pedal is what you ride while playing: opening it is louder and grittier, closing it is softer and cleaner (Drive Mode lets you change that relationship). Neither is a per-note dynamic like velocity would be.

How do I get a grittier, more modern overdrive?

Stay in Rotary mode and pick Transparent OD, Op-Amp Dist or Hot-Rod Crunch as the Amp Type in SETTINGS → ROTARY → Power Amp, then raise Drive. The default 122 Tube Amp overdrive is the warmer, rounder vintage sound.

Appendix: Parameter Reference

A compact reference of every control mentioned in this manual, in one place.

16. Support

Questions, license transfers, or anything account-related — email support@rubigo.audio. For general chat and community help, join the Discord server.

Trademarks

Hammond, B3 and Leslie are trademarks of Hammond Suzuki Co., Ltd. Rubigo Audio is not affiliated with, sponsored by, or endorsed by Hammond Suzuki. These names are used only to identify the instrument RB3 emulates.

VST is a registered trademark of Steinberg Media Technologies GmbH. CLAP is an open standard by Bitwig and u-he.

Third-Party Software

RB3 is built with these open-source components, used under their licenses:

The MIT and ISC licenses permit use, copying, modification and distribution, provided the copyright notice and the license text are included:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software
and associated documentation files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

(The ISC license of nih-plug grants the same permissions in shorter words, with the same condition and disclaimer.)

© 2026 Rubigo Audio. All rights reserved.