Spiral Electric FX Yellow Spiral Overdrive

The Spiral Electric FX Yellow Spiral Overdrive is an overdrive pedal designed by Tom Cram for his own company, Spiral Electric FX. It was the second stompbox Cram previewed at Premier Guitar's NAMM 2019 Stompbox Booth¹, and the circuit is based on the DOD 250 Overdrive Pre-Amp with what Premier Guitar's announcement called "choice alterations"².

Where the original DOD 250 gives you one gain structure, the Yellow Spiral builds on that circuit with its own set of alterations³. The pedal is also sold under the name Yellow Spiral Drive, and its circuit is likewise described as based around the classic DOD 250 Overdrive preamp². Cram's own experimental work with the 250 fed directly into the design, as he explained in a later interview⁴.

What it does

For a player, the Yellow Spiral is a low-to-mid gain drive that can also work as an always-on tone sweetener or a boost in front of an amp. Guitar.com's launch coverage described its intended range as "from an 'always-on' tone sweetener to clean/dirty boost to low-mid gain distortion"⁵. Because it is true bypass², it drops out of your signal path entirely when switched off, which suits a pedal you might leave on the board but not always engaged.

The pedal sits in a brushed aluminum chassis with laser-etched graphics and bright yellow knobs, a finish Gearnews described as "a very striking 'blasted' finish" that "looks pretty bulletproof in the photos"⁴.

The controls: Girth and the clipping toggle

The control set is Gain, Output, a six-position Girth rotary, and a three-way clipping toggle²⁴⁵.

The Girth control is the pedal's signature feature, and it later carried over to other Spiral Electric FX pedals: Premier Guitar noted that "The 'Girth' Control was first introduced with Spiral Electric FX's Yellow Spiral Drive" when covering the company's later White Spiral Boost⁶. Because it is a stepped rotary rather than a sweep knob, each position is a repeatable setting, useful if you switch guitars or amps and want to return to an exact amount of low-end lift.

The clipping toggle chooses between three voicings²:

• N2 + LED: Nanolog N2 carbon clipping mixed with an LED clipper²⁷
• N2: Nanolog N2 carbon clipping on its own²
• N2 + Silicon: Nanolog N2 mixed with silicon diodes²

Delicious Audio described the approach as "Nanolog's carbon clipping technology in combination with more traditional diodes"², and the JHS Pedals history of the company put it as "using N2 Nanalog and silicon components mixed with the LED clipper"⁷. In practice the toggle is a voicing choice: each combination of clipping components shapes the top end and the feel of the drive differently, so the same Gain setting yields three distinct textures.

A DOD 250 circuit by Tom Cram

The Yellow Spiral's family tree runs through the DOD 250, a circuit the press has repeatedly described in elevated terms: Pedal of the Day called it "the iconic DOD 250 overdrive circuit"⁸⁹, and Griffin Effects sells a DIY board based on it that can also build the DOD YJM308 and MXR Distortion + variants. The 250 has a documented history of being cloned and reworked, including by Josh Scott of JHS, who MusicRadar reported cloned unit #75 "with some help from DiFrancesco"¹⁰¹¹¹².

Tom Cram's connection to the circuit is a personal one. In a Guitar.com interview he said of his experimental work on the 250: "A lot of my experimental stuff with it became the Yellow Spiral"¹⁰. He has been called "the legendary Tom Cram"⁴ and described as a "former DigiTech mastermind"¹. The Yellow Spiral's basis in the DOD 250 is a thread running through the coverage of the pedal, from its NAMM 2019 preview onward⁷².

The Yellow Spiral is not the only Spiral Electric FX pedal built on this foundation; the same company's Yellow Spiral Drive page covers the pedal's launch coverage in more detail, and the line also grew to include the Red Spiral Drive Channel, which the JHS history says evolved from the DOD Looking Glass Drive circuit in 2020².

The LF351 Limited Edition

In 2022 Spiral Electric FX issued a Yellow Spiral LF351 Limited Edition Overdrive, a version built around what Pedal of the Day called "the tin-can LF351 opamp"⁸. The review described it as keeping with the original version of the Yellow Spiral Drive while offering "always on" tone sweetening, clean and dirty boosts, low-gain distortion and amp-pushing capabilities⁸.

Where the standard pedal's toggle selects clipping diodes, the LF351 edition carries a Texture Toggle with three settings: a Silicon 1N914 Schottky pair, a straight LF351, and a "secret part" option, which the review said gives "3 unique and distinct tonal flavors"⁸. It keeps the six-way Girth rotary, which the same review described as a "6-way rotary switch giving access to differing tonal settings, retaining highs while increasing the low-end 'girth' with each turn"⁸.

The reviewer's verdict on the limited edition was strongly positive on its individuality⁸:

The review also found the pedal touch-sensitive in use: "Extremely touch-sensitive, the Yellow Drive will go from chime to grind with a simple increase in pick attack," and noted that DOD 250 and Micro Amp boost sounds are readily available, with the pedal cleaning up well using the guitar's volume knob⁸.

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