Cornerstone is a boutique pedal builder run by Emilio Massari out of Milan, Italy 🇮🇹. Since 2015, this family biz has been crafting classic-rock flavoured pedals that blend vintage tones with modern tweaks.
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Today we’re diving into the Gladio — a compact preamp overdrive pedal inspired by one of the rarest and most hyped amps in guitar history: the Dumble Steel String Singer. Built as a simplified version of Cornerstone’s now-retired Gladio Double Preamp, this new version brings back the magic of Channel One, plus a clean blend knob to dial in extra clarity 🎚️.
But before we plug in, let’s take a quick stroll down Dumble lane 🚶♂️🎸
So what’s the deal with Dumble amps? 🤔
Howard “Alexander” Dumble was an eccentric genius who kicked off his amp career with Mosrite in the ‘60s, before doing his own thing in the ‘70s. He didn’t just build amps — he made you audition. You’d play for him, and he’d tweak the amp to suit your style ⚡
Because of that extreme customisation (and the fact that he built everything by hand), his amps became insanely rare. Today, if you can even find one, expect to drop over $100,000 💸
He famously never took apprentices, covered his circuits in epoxy to stop copycats, and went totally off-grid later in life. He passed away in 2022, but his legend only keeps growing 🌟
So, what’s inside the Gladio? 🛠️
The Gladio isn’t trying to be a Dumble clone, but it is chasing that sweet, saturated, tube-preamp magic. Here’s what you get:
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Tone – Smooth and musical EQ. Left = warm, right = bright, always tasteful 🎚️
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Clean – Blend in your dry signal for extra note clarity without killing your gain 💡
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Volume – Crank it up, plenty of output if you want to hit your amp hard 📈
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Gain – Adds saturation without losing detail. Thick, never harsh ⚙️
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Comp switch – Two modes of compression. Up = more squish, down = a little looser 🎛️
Inside, it’s all miniaturised surface-mounted goodness, plus an internal trimmer to tweak low-end response. The Gladio uses three JFET opamps — two TL072Cs and an LM4558 — likely responsible for gain, comp, and voicing 🔍
How does it sound? 🎧
Straight up: it’s lush. You get that smooth, articulate drive that feels like a tube amp. The tone knob is subtle and always musical, and the gain has punch without becoming rude. Want more note separation? Just blend in some clean signal — no need to back off the grit.
Think of it as a classy overdrive with tube-like compression baked in. Neat, warm, and very usable.
We had Kolya Chan from Large Mirage stop by to give it a spin. Watch the full demo on our YouTube channel — we tweak knobs, push it hard, and hear what this little unit can do 🎥
Final thoughts 💭
The Cornerstone Gladio Preamp is a refined, vintage-voiced overdrive with bags of character. It doesn’t just aim to sound like a Dumble — it captures the vibe of a great amp: expressive, dynamic, and rich in tone.
And let’s be honest — at $499 AUD, it’s a hell of a lot more realistic than dropping six figures on a rare-as-hell boutique amp 😅
Catch the full review and sound test over on our YouTube. More gear coming soon ⚡🎛️🎸
