The Diamond Pedals Cornerstone Overdrive is a dual-gain overdrive pedal from Diamond Pedals, a maker Pedal of the Day described as having "been making top of the line gear for many years now"1. What sets the Cornerstone apart from a single-knob drive box is its architecture: it uses two separate control knobs to drive two separate gain stages, arranged so that one behaves like a preamp and the other like a power amp, the way a two-stage amplifier would1.
The idea is familiar to players who think of their dirt in amp terms. Instead of one gain control doing all the work, the Cornerstone uses two separate control knobs to control two separate gain stages, with Gain 1 acting like a preamp and Gain 2 like a power amp, much like turning up a preamp and then a power section1.
Two gain stages: a preamp and a power amp
The Cornerstone's core feature is its pair of discrete gain stages. As Pedal of the Day's reviewer Mike B put it, the pedal "features multiple unique discrete gain stages," with each stage given its own knob1. The two stages are voiced to work like the two halves of an amplifier:
- Gain 1 works like a preamp, setting the initial drive character1
- Gain 2 works like a power amp, adding a second layer of gain on top1
For a player, this means the pedal can cover more ground than a single-stage overdrive. With its two different gain stages, it makes for a diverse and user-friendly piece of gear that will make your guitar and amp sound great, all from one box1.
The controls
The control set is small and focused: two gain knobs, a Mid knob, and a Bright toggle1.
| Control | What it does |
|---|---|
| Gain 1 | Sets the first gain stage, working like a preamp1 |
| Gain 2 | Sets the second gain stage, working like a power amp1 |
| Mid | Controls how much or how little midrange gets added into the mix1 |
| Bright switch | Cuts some of the high frequencies out; intended for switching between humbucker and single coil guitars1 |
The Bright switch is the one control aimed at a specific practical problem. It is, in the reviewer's words, "supposed to be utilized when switching back and forth between guitars with humbuckers and those with single coils," trimming the top end when a brighter guitar would make the pedal spiky1. The Mid knob is the tonal shaping tool, letting you decide how present the guitar sits in the mix1.
What the press said
Published coverage of the Cornerstone is limited, but the review that exists is positive. Pedal of the Day's Mike B, reviewing the pedal in October 2015, liked the two-stage design in particular1:
"I really like to 2 different gain stages on this Cornerstone, too, it really makes for a diverse and user-friendly piece of gear, and will make your guitar and amp sound great as well."
His verdict centers on versatility: the preamp and power amp split makes the pedal adaptable rather than a one-sound box, which is the same quality that draws players to dual-drive designs in general1.
Power and switching
The Cornerstone runs on standard 9V operation and accepts either a battery or a power supply, so it fits a typical 9V pedalboard supply without any special requirements1. It uses true bypass switching, which means the signal passes straight through when the pedal is disengaged rather than running through a buffer1.
The Cornerstone Overdrive is an older Diamond Pedals release, reviewed by the press in 2015. Diamond Pedals was later revived by SolidGoldFX, so availability of this specific model may differ from the maker's current lineup.
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Questions
Is the Diamond Pedals Cornerstone true bypass?
Yes. The Cornerstone Overdrive uses true bypass switching, so when the pedal is off your signal passes through without the circuit coloring it. It was listed among the pedal's features in Pedal of the Day's 2015 review of the pedal.
Can the Cornerstone run on a battery?
Yes. The pedal runs on standard 9V operation from either a battery or a power supply, so it works on a board with a 9V supply or on its own with a battery installed.
What does the Bright switch do on the Cornerstone?
The Bright toggle is meant for players who switch between guitars with humbuckers and guitars with single coils. It cuts some of the high frequencies out, taming the top end when the brighter pickup type would otherwise make the pedal sound harsh.
What does the Mid knob do on the Cornerstone?
The Mid knob controls how much or how little midrange gets added into the mix. Set it low for a scooped feel or push it up to help the guitar cut through a band, working alongside the two gain controls.
Sources (1)
- Diamond Pedals Cornerstone Overdrive, Pedal of the Day, 2015-10-21
