The Catalinbread Dirty Little Secret is a Marshall-in-a-box high-gain overdrive pedal made by Catalinbread of Portland, Oregon. Instead of modeling a Marshall with digital code, it uses an all-discrete JFET circuit to reproduce the behavior of a plexi-era amp, and Delicious Audio has written that Portland's Catalinbread "built its reputation on the Dirty Little Secret, a Marshall-in-a-box that conquered high-gain British roar"12. The pedal gives you two amp voicings, Super Lead and Super Bass, and a set of amp-style controls, in an enclosure small enough for a crowded pedalboard3.
Guitar World has described its appeal plainly: it is "a top-tier option for players whose tastes in electric guitar tone were shaped by the Marshall amps of the late '60s and early '70s, but sadly, like the rest of us, don't really have the space nor the opportunity to grab one of these vintage amplifiers, turn it up and push air around the room"4.
Super Lead and Super Bass modes
The Dirty Little Secret's defining feature is its two voicings, selected by a switch. On the standard pedal this is an internal slider switch inside the enclosure29. Catalinbread describes the difference in amp terms: Super Lead mode is "a cutting, upper-midrange-heavy tone," while Super Bass mode is "a smoother, smokier tone with a lower midrange emphasis"7.
MusicRadar's reviewer Trevor Curwen characterized the two modes by their amp ancestry: Super Lead is "based on a later 'plexi' model having more gain and a different tonestack with more upper mids," while Super Bass is "more akin to early Marshalls or the Bassman it was based on, with less prominent midrange and lower gain"10. Catalinbread's own press release explained the modes with a circuit comparison: the difference "is akin to split-cathode vs. shared-cathode configuration on an old Marshall; split-cathode has a high-pass response starting around 700hz while shared-cathode lets everything through"2.
| Mode | Character | Amp reference |
|---|---|---|
| Super Lead | Cutting, upper-midrange heavy, more gain710 | Later plexi Super Lead10 |
| Super Bass | Smoother, smokier, lower midrange, lower gain710 | Early Marshalls and the Fender Bassman they were based on10 |
The mode switch does more than swap a voicing. MusicRadar reported that it "completely reconfigures the tone stack and key first gain stage parameters to give authentic Super Lead or Super Bass type response"11. On the MkIII, the gain range "goes from classic plexi all the way to modified JCM800 levels and can get even more raw and open than any previous DLS," according to Catalinbread's product text12.
Controls and the presence adjustment
The control set is amp-like rather than pedal-like. Pedal of the Day's review describes it simply: "Loudness make is louder or softer and Gain goes from mild grit to full-on, crunchy, Marshall-y overdrive"3. The Red Mod and DLS Red versions carry a full three-knob treble, middle and bass complement that "reproduces exactly the tone circuits of the Super Lead and Super Bass amps"1314.
Presence is handled differently depending on the version:
- Standard DLS: an internal presence pot "dials in the top end to suit your rig"10, which Catalinbread describes as a trimmer that lets you "fine-tune the presence of the pedal precisely to your guitar and amp combination"12.
- Red Mod and DLS Red: a hidden Presence trim-pot "accessible by removing the bottom plate," for fine-tuning presence and high treble frequencies1514.
- Deluxe: the Presence control is externalized as a knob on the outside of the pedal167.
On the standard Dirty Little Secret, both the Super Lead/Super Bass mode switch and the presence adjustment are inside the enclosure. Guitar Pedal X noted that earlier compact editions had the switch as "an awkward-to-reach internal dip-switch"8. If you want both controls on the surface, the Dirty Little Secret Deluxe moves the mode selection to an external toggle and the presence to an external knob716.
Power
The standard Dirty Little Secret runs on a 9 to 18V DC power supply, sold separately, drawing 5mA5. Catalinbread notes on the related DLS Red page that if "you want more volume, headroom, and percussive attack, try running an 18-volt power supply"17. The Dirty Little Secret Deluxe differs: it takes a center-negative 9V DC supply with at least 7mA of current7.
History and versions
The Dirty Little Secret has gone through several revisions since its introduction. The MkII was released in 2011 and was traced by Aion FX in 2020; its tone stack was labeled "Fullness" and "Presence" rather than the more familiar Bass and Treble6. In 2013 it was replaced by the MkIII, "a full redesign which is still in production today"6. Catalinbread's press release for the redesign said the JFETs used as the base for the pedal had been discontinued, prompting the rework, and that the company was able to take everything it loved about the MkII and expand on it2. The redesigned pedal became available on February 12, 2013, priced at $169.992.
In 2019 Catalinbread issued two red-enclosure variants. The Limited Edition Dirty Little Secret Red Mod, announced in July 2019 at $189.99, was a hot-rodded version with "a more refined set of gain stages that cuts through the low-mids of the original and brings you both extended punch and clarity"1315. Guitar.com summarized its changes as "a sliver of gain added to both Super Lead and Super Bass drive voicings" and "a more hi-fi EQ section"18. gearnews described the result as "a Plexi Plus" and reported a limited release of only 100 units worldwide15. In November 2019 came the DLS Red, an updated hot-rodded version hand-built in Portland with a 4 year warranty, available for $189.991419.
In September 2023 Catalinbread launched the Dirty Little Secret Deluxe. What began as a fourth version of the flagship circuit grew into a bigger-enclosure pedal that reaches "beyond the preamp circuit and adding the rest of the amp," with a phase inverter, power amp sim and output transformer, plus a boost side that ships before the DLS side so you can "push the whole arrangement into gooey saturation at will with a single stomp"78. It was available from September 20234.
| Version | Year | What changed |
|---|---|---|
| MkII | 20116 | Tone stack labeled Fullness and Presence6 |
| MkIII | early 20139 | Full redesign, SL/SB modes, more gain619 |
| Red Mod | 2019, 100 units15 | Hot-rodded gain stages, red enclosure, $189.991513 |
| DLS Red | November 201914 | Updated hot-rodded version, $189.9919 |
| Deluxe | September 20234 | Bigger enclosure, external toggle and Presence, boost side47 |
What reviewers said
MusicRadar's Trevor Curwen found the tone knobs "offer the sort of organic control you'd get with an amp" and that "both modes sound excellent, providing a range of drive with familiar British tonal signature," summing it up as "a versatile tone-building dirt box with two distinct M-style flavours"10. Pedal of the Day's Mike B wrote that while "lots of pedals make the same claim that you can get a true Marshall tone out of any amp, and most fall short. Not the case with the Dirty Little Secret," adding that a used one could be found "for a little over $100 if you are patient"3.
On That Pedal Show, Dan and Mick compared it against the Fulltone OCD in a five-and-a-half-minute AB segment20. Mick's take: "I really really really like the Dirty Little Secret... it's very vibby it's it's got a real classic tone going on to it," while noting the OCD "is more overdrive pedal" by comparison21.
"this is the best Marshall-in-a-box pedal I've come across."
Depper's pedalboard feature also noted the pedal's two modes selectable via the internal slider22. Guitar Pedal X's Stefan Karlsson was more measured, calling the compact DLS "a decent Plexi type for sure" while noting it has "never quite been one of my own absolute favourites," and that Andy Martin "has long cited the Dirty Little Secret as his favourite MIAB"8.
That Pedal Show returned to the pedal in a September 2025 demo of five underappreciated overdrives, alongside pedals from Empress, Xotic, Crowther and Crazy Tube Circuits23.
In that video the show demos the Dirty Little Secret among the five pedals, covering its Marshall voicing and how it sits against the others23.
Related pedals
Catalinbread's amp-in-a-box range includes several other pedals built on the same idea of a specific amp in a stompbox, including the Dirty Little Secret Deluxe, the DLS Red, the Dirty Little Soda (DLS Red), the DLS MKII, and the low-gain, Bluesbreaker-inspired Clean Little Secret announced in 20267.
Videos
ProGuitarShopDemos
News
Questions
Where is the mode switch on the Dirty Little Secret?
On the standard Dirty Little Secret it is an internal slider switch inside the enclosure, so you have to open the pedal to change between Super Lead and Super Bass voicings. The Dirty Little Secret Deluxe moves this to a toggle switch on the outside of the pedal, which Catalinbread calls the Voice toggle, so you can switch modes without tools.
What is the difference between the Dirty Little Secret MKII and MKIII?
The MkII, released in 2011, used a tone stack labeled Fullness and Presence rather than the familiar Bass and Treble. The MkIII, released in early 2013, was a full redesign with a Super Lead and Super Bass mode switch, more gain than the original, and a treble, middle and bass tone control set. The MkIII is the version still in production.
What is the Dirty Little Secret Red Mod?
A limited edition version of the Dirty Little Secret in a red enclosure, announced in July 2019 and priced at $189.99. Catalinbread described it as a hot-rodded version with a more refined set of gain stages that cuts through the low-mids of the original, plus a sliver of extra gain on both voicings and a more hi-fi EQ section. Only 100 units were made.
How do you adjust the presence on the Dirty Little Secret?
On the standard pedal, presence is set by an internal trim pot that lets you fine-tune the top end to your guitar and amp. On the Red Mod and DLS Red it is a trimpot reached by removing the bottom plate. The Dirty Little Secret Deluxe externalizes this as a regular Presence knob on the outside of the pedal.
Is the Dirty Little Secret still made?
Yes. The MkIII, released in early 2013, is described by Aion FX as still in production today, and Catalinbread's product pages list the pedal as hand-made in Portland, Oregon. A larger Dirty Little Secret Deluxe version has also been available since September 2023.
How many Dirty Little Secret Red Mod pedals were made?
The Red Mod was a limited release of only 100 units available worldwide, according to gearnews when it was announced in July 2019. It was priced at $189.99, or USD 189 RRP as gearnews put it.
Sources (23)
- New Pedal: Catalinbread Clean Little Secret, Delicious Audio, 2026-05-04
- Catalinbread Launches Updated Dirty Little Secret, Premier Guitar, 2013-02-06
- Catalinbread Dirty Little Secret Drive, Pedal of the Day, 2014-08-02
- “A fully customizable amp-in-a-box experience”: Has Catalinbread's Dirty Little Secret Deluxe just redefined amp-like overdrive pedals?, Guitar World, 2023-09-07
- Dirty Little Secret (B-Stock), Catalinbread Effects
- Triton Preamp Drive Mk. II / Catalinbread DLS V2, Aion FX, 2020-11-23
- Dirty Little Secret Deluxe, Catalinbread Effects
- Guitar Pedal X, Guitar Pedal X, 2023-09-14
- Triton Preamp Drive Mk. III / Catalinbread DLS V3, Aion FX, 2020-11-27
- Catalinbread Dirty Little Secret review, MusicRadar, 2016-01-15
- Catalinbread launches redesigned Dirty Little Secret, MusicRadar, 2013-02-07
- Guitar FX Layouts: Catalinbread DLS MKIII, tagboardeffects.blogspot.com (Guitar FX Layouts), 2013-04-27
- Catalinbread Announces New Limited Edition Dirty Little Secret Red Mod, Guitar World, 2019-07-03
- Catalinbread Unveils New Dirty Little Secret Red Pedal, Premier Guitar, 2019-11-28
- Catalinbread Limited Edition Dirty Little Secret Red Mod, gearnews.com, 2019-07-03
- Catalinbread Dirty Little Secret Deluxe, Delicious Audio, 2023-09-22
- Dirty Little Soda (DLS Red), Catalinbread Effects
- Catalinbread’s Dirty Little Secret gets a limited-edition mod, Guitar.com, 2019-07-03
- Catalinbread's Dirty Little Secret overdrive pedal just got a little bit dirtier, Guitar World, 2019-12-06
- TPS AB Comparisons, That Pedal Show, 2017-01-03
- TPS AB Comparisons, That Pedal Show, 2017-01-03
- Pedalboard Feature: Dave Depper, Strymon, 2015-10-05
- Underappreciated Overdrive Pedals, That Pedal Show, 2025-09-12
