Tom Morello Marshall JCM800 Settings
Tom Morello's approach to the guitar is categorically different from most players in this guide. He does not use the amp for distortion in the conventional sense — the JCM800 runs relatively clean and pushed into mild breakup by his picking attack. The dramatic effects in his sound come from techniques and specific pedals, not from a high-gain amp channel.
The Amp: Marshall JCM800 Channel 1 (Clean)
Morello uses a Marshall JCM800 2205, run primarily on Channel 1 in Clean mode — not the high-gain second channel.
JCM800 Channel 1 settings:
Volume (Channel 1): 8
Treble: 7
Middle: 6
Bass: 5
Presence: 6
The Volume at 8 on Channel 1 pushes the amp into mild natural saturation — not full-gain crunch, but a degree of compression and warmth. The amp's natural breakup at this volume contributes to the feel without providing the dramatic distortion of a high-gain channel.
No gain pedals — Morello does not use overdrive or distortion pedals. The amp provides all the gain, and the signal manipulation techniques provide the dramatic effects.
The Guitar: Custom Arm the Homeless / Axis
Morello's primary RATM guitar is a custom instrument called "Arm the Homeless" — built around a Fender Jaguar body with various components. Key features:
- Single humbucker (Seymour Duncan) in the bridge position
- Killswitch — a momentary switch that cuts the signal completely when pressed
- Toggle switch — the pickup selector used rhythmically to create the rapid switching sound
DigiTech Whammy Settings
The DigiTech Whammy is the most important effect in Morello's arsenal:
For "Killing in the Name" and turntable scratch sounds:
- Mode: +2 Octave (shifts up two octaves when pressed)
- Expression: Heel down = no effect; toe down = +2 octaves
- Whammy engages as a brief pitch shift to create "scratch" sounds
For "Bombtrack" and sustained pitch shifts:
- Mode: Harmony (+5th or +7th) or Dive Bomb
- Sustained pedal position for orchestral pitch shift effects
For "Calm Like a Bomb":
- Mode: -1 Octave
- The bass-like lower octave creates a heavier rhythm character
Killswitch Technique
The killswitch creates the stuttering, on/off percussive chop effect:
- Rapid pressing and releasing the switch creates the rhythm
- Timing is synced to the song's tempo
- The JCM800's natural compression makes the killswitch cuts more musical — abrupt digital silence would sound different
Replicating without a killswitch:
- A volume pedal, pressed rapidly with the foot
- A kill switch wired by a luthier (any guitar can have this done)
Signal Chain
Guitar → DigiTech Whammy → Dunlop Cry Baby Wah (occasionally) → Marshall JCM800 Channel 1
There are no overdrive, distortion or fuzz pedals in the RATM-era chain. The entire texture comes from the guitar's toggle switch, killswitch, Whammy, and Morello's picking technique.
Replicating the "Arm the Homeless" Sound
The tapping, Whammy, and toggle switch sounds require technique rather than specific amp settings:
- Whammy pedal (+2 octave mode) — available new for ~$100
- Fretboard tapping — left hand taps the highest frets while right hand holds the Whammy toe-down position
- Toggle switch rhythm — rapid back-and-forth between two pickup positions (neck/bridge) creates the "scratching" sound
The JCM800 clean tone provides the foundation; all the distinctive Morello sounds come from these techniques.
Replicating on Modellers
Line 6 Helix
Amp: JCM800 model (Brit 800), Channel 1
Drive 2.5, Bass 5, Mid 6, Treble 7, Presence 6
Pitch: DigiTech Whammy model — set for +2 octave. This is the key effect, not amp gain.
Fractal Axe-FX III
Amp: JCM800 2205 Rhythm Channel at moderate gain
Add Whammy/Pitch model. The technique cannot be modelled — it must be performed.
Why the Amp Is Deliberately the Least Interesting Part of This Rig
Every other artist amp guide on this site treats the amplifier as a primary character-defining element. Morello's Channel 1 clean-ish JCM800 setting is deliberately the opposite — it's a stable, relatively neutral platform specifically so the dramatic pitch-shifting, filtering, and signal-interrupting techniques layered on top remain clearly audible and distinct. An amp with more of its own gain and character would blur the edges of these techniques, making the Whammy's octave shifts and the killswitch's stutters sound less precise and less shocking against the backdrop.
This is worth internalizing before spending on amp upgrades to chase this tone: a genuinely excellent, characterful high-gain amp works against this specific rig's design logic. The relatively plain, clean-pushed JCM800 setting is correct precisely because it's unremarkable on its own.
Common Mistakes
Upgrading to a higher-gain amp channel expecting a "better" version of this tone. As explained above, the JCM800's relatively clean Channel 1 is a deliberate choice that lets the signal-manipulation techniques read clearly — a higher-gain channel muddies exactly the precision this rig depends on.
Treating the custom "Arm the Homeless" guitar's killswitch as essential, irreplaceable hardware. As the FAQ below confirms, any guitar can have a comparable killswitch wired in, or a volume pedal tapped rapidly achieves a similar practical result — the specific custom guitar isn't a hard requirement for the technique.
Assuming the toggle switch and killswitch techniques can be modeled or automated. As the modeller replication section states plainly, "the technique cannot be modelled — it must be performed" — these are genuinely physical, real-time performance techniques, not settings that can be dialed in and left alone.
Skipping the Whammy pedal and trying to approximate its effects with other pitch tools. As the DigiTech Whammy section shows, its specific modes (+2 Octave, Harmony, Dive) are used across multiple signature songs — a generic pitch-shift plugin or different pedal design won't replicate the exact tracking and response character Morello's parts depend on.
ToneStakr's Take
For players building this rig, resist the instinct to make the amp more interesting or higher-gain — the relatively plain Channel 1 clean-pushed JCM800 setting is correct as written, and the DigiTech Whammy is where the actual budget and practice time should go. Getting the killswitch or toggle-switch techniques physically comfortable matters more than any amp upgrade for capturing the recognizable RATM sound.
Frequently Asked Questions
What is the killswitch effect?
A momentary switch wired into the guitar to cut the signal completely to zero when pressed — rapid on/off pressing creates the stuttering, percussive chop effect heard prominently on "Killing in the Name" and other RATM tracks.
Can any guitar have a killswitch installed?
Yes — any guitar can be wired with a momentary killswitch by a competent luthier at a relatively modest cost. Morello's custom "Arm the Homeless" guitar has one built in, but it's not proprietary technology; the modification is broadly accessible.
What is the "Arm the Homeless" sound?
Left-hand fretboard tapping combined with the DigiTech Whammy set to +2 Octave mode, creating a turntable-scratch imitation — the rhythmic toggle switch technique also contributes to the overall percussive, DJ-adjacent texture.
What amp setting does this tone require?
A Marshall JCM800 on Channel 1 (relatively clean), pushed into mild natural breakup by picking attack rather than amp gain — the apparent "dirt" in the sound comes from the signal manipulation techniques layered on top, not from amp saturation.
Is it worth using a modeller to replicate Morello's amp tone rather than a real Marshall?
Reasonably, for the amp foundation — a JCM800 model at the settings described gets you a close approximation of the clean-pushed platform. However, as the guide states, the signature techniques (killswitch, toggle-switch scratching, Whammy performance) can't be modeled or automated; they require genuine physical technique regardless of the amp source.
Why does Morello avoid reverb in this rig?
The JCM800's natural room character and stage ambience provide sufficient sense of space for RATM's aggressive, rhythmically precise material — adding reverb would soften the tight, percussive attack that the killswitch and toggle-switch techniques depend on for clarity.