Earthquaker Devices Grey Channel

The EarthQuaker Devices Gray Channel is a dual overdrive and fuzz pedal that puts two DOD 250 style circuits in one box. Guitar Pedal X describes it as a "Dual DOD250 style Overdrive / Fuzz"¹, and the Guitar FX Layouts write-up calls it "A dual overdrive based on the classic grey spec DOD 250"². The DOD 250 is one of the simplest and most copied overdrive circuits, so the Gray Channel essentially gave players two of that circuit, each with its own gain and level, plus switchable clipping choices.

Clipping options

What set the Gray Channel apart from a plain DOD 250 clone was the range of clipping choices. The Guitar FX Layouts notes list "multiple clipping options including germanium and MOSFET"², and the builder adds that "they all offer something unique too"². On the germanium setting, the builder reports the option is "pretty awesome" and that a 1N34A germanium diode works well in that position². For players, that means one pedal could cover anything from a soft, open overdrive to a harder clipped drive or fuzzier edge, depending on which clipping pair is selected.

The DIY layout and its mods

The Gray Channel has a second life among hobbyist builders. David of Perf & PCB Effects Layouts recreated the circuit and published it on his website; the schematic did not come from an original EQD pedal². The stripboard layout on Guitar FX Layouts is drawn from that recreation².

Builders discussing the layout have documented several changes:

• Swapping both 470K resistors connected to Gain3 for 4K7, both volume pots to B100K, and both gain pots to C500K, which matches DOD 250 schematic values²
• Changing the 47k resistor before Gain 3 to 4.7k for much more gain; one builder reported "There is so much more gain"²
• Replacing the 1M linear gain pot with a C100K pot to fix on-off gain behavior²

A few practical notes from the same discussion: the on-off-on switches used for clipping selection are SPDT, not SPST², and the Channel footswitch's center pole wiring differs depending on whether a common cathode or common anode bicolor LED is used². The layout uses a 1458 IC².

On bass: builders asked whether the layout works as a bass overdrive, but no confirmed success is documented; one commenter's take was "If not I guess it's mod time"². Players looking for a bass tuned take on EarthQuaker's overdrive approach may want the Blumes or the Westwood family instead.

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