Catalinbread · Overdrive

Catalinbread Dirty Little Secret Settings Guide

The Catalinbread Dirty Little Secret (DLS) models the preamp circuit of a Marshall Super Lead run at high volume through a discrete transistor circuit. It's one of the most accurate Marshall-in-a-box designs at any price — capturing the specific gain structure, mid-forward EQ, and dynamic response of a cranked Plexi-era Marshall. The Red version (Mk III) adds a voicing switch for different Marshall characters (JTM45 vs. Super Lead).

The best Catalinbread Dirty Little Secret settings start with: Volume at 6/10, Gain at 6/10, Bass at 5/10, Mid at 6/10, Treble at 6/10, Presence at 6/10. Adjust from there based on your amp, guitar, and room volume. For Classic Rock: Volume 6/10, Gain 6/10, Bass 5/10, Mid 7/10, Treble 6/10, Presence 6/10.

What Each Control Does

Volume
Off
Loud
Output volume
Gain
None
Full
Preamp gain / overdrive amount
Bass
Thin
Thick
Low-frequency EQ
Mid
Scooped
Forward
Midrange presence — Marshall's characteristic mid honk
Treble
Dark
Bright
High-frequency EQ
Presence
Smooth
Cutting
Top-end definition — equivalent to Marshall Presence control

Recommended Starting Settings

Safe starting positions for any style. Adjust from here based on your amp and room.

6
Volume
6
Gain
5
Bass
6
Mid
6
Treble
6
Presence

All values on a 0–10 scale. These are starting points — fine-tune by ear.

Settings by Genre

Classic Rock
Volume6
Gain6
Bass5
Mid7
Treble6
Presence6

Mid-forward Marshall crunch — the DLS at these settings produces the characteristic mid-honk of a cranked 1959 Super Lead. Mid at 7 captures the "honky" quality that sounds nasal in isolation but cuts through a band mix superbly. This is the classic rock rhythm tone of Zeppelin, AC/DC, and early Van Halen.

Blues-Rock
Volume6
Gain4
Bass5
Mid7
Treble7
Presence7

Lower Gain with elevated Mid, Treble, and Presence for blues-rock lead. The DLS at Gain 4 is dynamic and pick-sensitive — harder picking produces more saturation, lighter playing cleans up. Presence at 7 adds the top-end cut that blues-rock lead lines need to sing over rhythm parts.

Hard Rock
Volume6
Gain8
Bass5
Mid6
Treble6
Presence7

Higher Gain for more aggressive hard rock — the DLS approaches full Marshall-saturation territory at Gain 8–9. Presence at 7 maintains definition at high Gain settings. Still the Marshall character at heart: mid-focused, harmonically rich, different from a Mesa or Peavey high-gain circuit.

Metal (JTM45 voicing)
Volume6
Gain9
Bass6
Mid5
Treble6
Presence8

On Mk III units, the voicing switch set to JTM45 gives a slightly looser, more vintage low end than the Super Lead setting — combined with maximum Gain and Presence for a heavier, more saturated rhythm tone than the pedal default.

Clean Boost (low Gain)
Volume7
Gain1
Bass5
Mid6
Treble6
Presence5

Minimum Gain with Volume above unity turns the DLS into a mid-forward clean boost, pushing a clean amp toward its own natural breakup rather than adding the pedal own distortion character.

Tips & Common Mistakes

  • The DLS is most effective into a clean amp that can absorb the pedal preamp circuit and add its own power-amp response. Into an already-dirty amp it stacks but loses the specific Marshall character. A Fender Twin or Hiwatt-style clean amp is ideal.
  • The Presence control on the DLS mirrors a Marshall amp Presence control — it affects high-frequency feedback in the modeled power amp stage, not just treble. High Presence adds a different kind of brightness than the Treble control.
  • Guitar volume-knob cleanup works convincingly on this circuit, consistent with its real-Marshall-preamp modeling — rolling back from 10 to 6-7 thins the gain into a lightly gritty clean tone without switching the pedal off.
  • On Mk III units, audition both voicing-switch positions (JTM45 and Super Lead) with your specific amp and guitar before settling — the difference is subtle in isolation but meaningful in a full band mix.
  • Because Mid defaults to a forward, honky voicing true to the source amp, players coming from scooped-mid high-gain pedals may want to back Mid off 1-2 points to taste rather than assume the default is wrong.
  • Stacking this pedal after a treble-boost or clean boost pushes the modeled preamp harder without adding a second distinct distortion character, closely matching how the source amps were actually driven.

Catalinbread Dirty Little Secret — Common Questions

Best starting settings for Catalinbread Dirty Little Secret: Volume at 6/10, Gain at 6/10, Bass at 5/10, Mid at 6/10, Treble at 6/10, Presence at 6/10. Adjust from there based on your guitar, room, and playing style.

For Classic Rock: Volume 6/10, Gain 6/10, Bass 5/10, Mid 7/10, Treble 6/10, Presence 6/10. Mid-forward Marshall crunch — the DLS at these settings produces the characteristic mid-honk of a cranked 1959 Super Lead. Mid at 7 captures the "honky" quality that sounds nasal in isolation but cuts through a band mix superbly. This is the classic rock rhythm tone of Zeppelin, AC/DC, and early Van Halen.

For Blues-Rock: Volume 6/10, Gain 4/10, Bass 5/10, Mid 7/10, Treble 7/10, Presence 7/10. Lower Gain with elevated Mid, Treble, and Presence for blues-rock lead. The DLS at Gain 4 is dynamic and pick-sensitive — harder picking produces more saturation, lighter playing cleans up. Presence at 7 adds the top-end cut that blues-rock lead lines need to sing over rhythm parts.

Volume: Output volume (Off to Loud). Gain: Preamp gain / overdrive amount (None to Full). Bass: Low-frequency EQ (Thin to Thick). Mid: Midrange presence — Marshall's characteristic mid honk (Scooped to Forward). Treble: High-frequency EQ (Dark to Bright). Presence: Top-end definition — equivalent to Marshall Presence control (Smooth to Cutting)

The DLS is most effective into a clean amp that can absorb the pedal preamp circuit and add its own power-amp response. Into an already-dirty amp it stacks but loses the specific Marshall character. A Fender Twin or Hiwatt-style clean amp is ideal. The Presence control on the DLS mirrors a Marshall amp Presence control — it affects high-frequency feedback in the modeled power amp stage, not just treble. High Presence adds a different kind of brightness than the Treble control. Guitar volume-knob cleanup works convincingly on this circuit, consistent with its real-Marshall-preamp modeling — rolling back from 10 to 6-7 thins the gain into a lightly gritty clean tone without switching the pedal off. On Mk III units, audition both voicing-switch positions (JTM45 and Super Lead) with your specific amp and guitar before settling — the difference is subtle in isolation but meaningful in a full band mix. Because Mid defaults to a forward, honky voicing true to the source amp, players coming from scooped-mid high-gain pedals may want to back Mid off 1-2 points to taste rather than assume the default is wrong. Stacking this pedal after a treble-boost or clean boost pushes the modeled preamp harder without adding a second distinct distortion character, closely matching how the source amps were actually driven.

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