The Cornerstone Music Gear Gladio SC is a single-channel analog overdrive preamp pedal, handmade in Italy12. It is based on the first channel of the larger Cornerstone Gladio, with what the maker calls "the exact same sound and controls, except the new CLEAN knob"3. Where the full Gladio is a dual preamp, the SC packs one channel of it into a smaller box and adds a parallel clean blend aimed at a specific target: the Stevie Ray Vaughan sound, which Cornerstone notes was achieved using a Dumble amplifier3.
Cornerstone describes the Gladio family as "not just an overdrive; it's a realistic tube-compression preamp able to take the sound into saturation" while retaining a touch-sensitive response4. Delicious Audio has characterized the Gladio as "an amp-in-a-box inspired by the rare line of Dumble amps"5. On That Pedal Show, Mick Taylor and Daniel Steinhardt discussed the Gladio in their episode on preamps versus overdrive pedals, using it as their example of the preamp side of that comparison6.
An analog overdrive preamp
The Gladio SC sits in the overdrive lane, but its maker frames it as a preamp as much as a drive pedal. Cornerstone's page for the Gladio V2.1 describes the circuit as "an Overdrive with a realistic tube-compression behavior"74, and the original Gladio Double Preamp page goes further, calling it a tube-compression preamp rather than a straightforward overdrive74. Guitar.com's review of the double preamp listed it simply as a "Dual overdrive pedal, made in Italy"8, which is the practical reading: it is a drive pedal voiced and structured to behave like a pushed amp.
That amp-like feel is what reviewers picked up on. Pete Thorn, reviewing the SC on his YouTube channel in March 2021, said9:
"it sounds more like i'm playing through maybe like my sir hedgehog or something like that with the drive switched in"
His point was that the SC does not read as a pedal stacked in front of an amp so much as the sound of an amp with its own drive engaged9.
The Clean knob
The Clean knob is the SC's defining feature and the reason it exists as a separate model. Cornerstone explains that the clean signal is taken directly at the input of the pedal and mixed back with the overdriven signal at the output, and that the CLEAN knob manages the volume of that clean signal, giving you a "clean layer" on top of the overdrive3. The maker breaks its effect into three parts:
| Aspect | What the Clean knob does |
|---|---|
| Bottom end | The sound becomes fatter as it is turned up3 |
| Compression | The non-compressed clean sound comes into the mix, with the change particularly accentuated on the attack3 |
| Saturation | The final output becomes hotter and better able to push the front end of the amp3 |
Cornerstone also notes that the knob's effect is noticeable within roughly the first 40% of its rotation, so most of the useful range sits early in the sweep3. Guitar.com's review lists the full control set as independent gain, volume, tone and Clean controls, plus a comp switch and an internal trimmer to adjust low end response2.
The Stevie Ray Vaughan angle
Cornerstone is explicit about the design goal: "the Gladio SC tries to take a step closer to the Steve Ray Vaughan sound, which was achieved using a Dumble amplier too"3. RockBoard's PedalPedia entry carries the same framing, with the tagline "Start your Texas blues journey here"1. Pete Thorn described the intent in similar terms, saying "what they were trying to do is give you a little bit more of that steel string singer stevie ray vaughan thing" via the clean blend9.
Guitar World has noted that many of Cornerstone's previous releases centered on emulating the tones of classic players such as Stevie Ray Vaughan and Robben Ford10. It is worth being clear about what the SC is and is not: it is a Dumble-style amp-in-a-box93, not a Tube Screamer clone. Stevie Ray Vaughan's best-documented drive pedal was the Ibanez TS-808, which Analog Man's history says he used "for his trademark juicy strat tone"11, but that is a different circuit from the Gladio's Dumble-inspired preamp design.
What reviewers said
Guitar.com's Ed Oleszko reviewed the Gladio SC in March 2022 and was positive about both the build and the sound, writing that "Not only do we admire the Gladio SC's high-end looks and sophisticated sounds"2. Pete Thorn's verdict centered on the amp-like feel described above9.
Where it sits in the Gladio line
The SC is the compact, single-channel option. The family it belongs to:
- Gladio SC: a single-channel pedal from Cornerstone Music Gear3
- Gladio Double Preamp / V2.1: the two-channel original7
- Gladio MkIII: another pedal from Cornerstone Music Gear shown alongside the SC on the maker's page1
Other Cornerstone pedals shown on the same page include the Nero, Aquarium and NUCLEO1.
The SC sits in a wider Cornerstone Music Gear line: alongside the Gladio MkIII, the maker's page also shows the Nero, Aquarium and NUCLEO1.
The Gladio SC runs on a 9V DC power supply only, with a 2.1mm center negative plug, and has no battery option12. At 60mA it is easy to power from a standard pedalboard supply1.
Videos
Pete Thorn
Cornerstone Music Gear
Cornerstone Music Gear
Questions
What power does the Cornerstone Gladio SC need?
It runs on a 9V DC power supply only, with a 2.1mm center negative plug, and draws about 60mA. There is no battery option, so it needs a spot on a pedalboard power supply. A standard 9V center negative output from most isolated supplies will work.
Is the Gladio SC analog?
Yes. RockBoard's PedalPedia entry for the Gladio SC lists its circuit type as analog. It is a single-channel overdrive preamp built around the first channel of the larger Cornerstone Gladio, with the same sound and controls plus a new Clean knob.
What does the Clean volume knob do on the Gladio SC?
It controls the volume of a parallel clean signal, taken directly at the pedal's input and mixed back with the overdriven signal at the output. Turning it up makes the sound fatter, adds uncompressed clean signal that changes the feel of the attack, and makes the final output hotter and better able to push an amp's front end.
Is the Gladio SC meant for Stevie Ray Vaughan tones?
Cornerstone says the Gladio SC tries to take a step closer to the Stevie Ray Vaughan sound, which was achieved using a Dumble amplifier. Pete Thorn described the design as aiming at the Steel String Singer, Stevie Ray Vaughan thing via the Clean knob. It is an amp-in-a-box take on that territory, not a copy of his Tube Screamer setup.
What is the Cornerstone Gladio MkIII?
The Gladio MkIII is an updated version of the double preamp released in October 2026. According to Delicious Audio, it rebuilds the Gladio around player requests, adding front-panel controls, a Channel 2 Ratio clean blend, 30V internal headroom and 4-jack routing. The Gladio SC remains the compact single-channel option.
Sources (11)
- Gladio SC by Cornerstone Music Gear, RockBoard PedalPedia, 2026
- Cornerstone Gladio SC review: The most pedalboard-friendly Dumble pedal around?, Guitar.com, 2022-03-01
- Gladio SC, Cornerstone
- Gladio | Cornerstone | Handmade in Italy Music Gear, Cornerstone
- Cornerstone Nero Fuzz, Delicious Audio, 2024-09-16
- What Is A Guitar Preamp & Why Would You Have One?, That Pedal Show, 2020-09-18
- Gladio V2.1, Cornerstone (cornerstonegear.it)
- Review: Cornerstone Gladio Double Preamp, guitar.com, 2021-01-14
- THE BEST "DUMBLE IN A BOX!" CORNERSTONE GLADIO SC PREAMP, YouTube (Pete Thorn channel), 2021-03-20
- “Usually you hear it coming out of your amp. Here, you feel it all around you”: Paul Davids once visited a nuclear power plant to find the world's most incredible reverb, Guitar World, 2024-10-07
- Ibanez Tube Screamer History, analogman.com, 2023
Pete Thorn
