The Coriolis Effects Grissom Young Dual Fuzz II is a limited dual fuzz pedal, a compact second take on the Spaceman Gemini III, which Spaceman Effects markets as a Dual Fuzz Generator1. It is built by Devin McNeilly of Coriolis Effects, and Guitar Pedal X describes it as "An improved fully variable take on Spaceman's Gemini III"2. Only 9 units of the edition were made, listed at $269 as of December 202532.
What it is and how it is controlled
The pedal carries two gain stages, one germanium and one silicon, blended together. The controls are Master, a Filter / Tone Sweep Direction switch with invert, Filter / EQ, a fully variable Ge Gain, Blend, and a fully variable Si Gain2. The fully variable mini Gain knobs are the headline change: the original Grissom Young Dual Fuzz had 3 switchable Gain settings per side, while the II replaces those switches with continuous knobs3.
| Control | Function |
|---|---|
| Master | Output level |
| Filter / Tone Sweep Direction switch / invert | Sweep direction of the filter |
| Filter / EQ | Tone shaping |
| Ge Gain | Fully variable germanium gain |
| Blend | Mix of the two fuzz stages |
| Si Gain | Fully variable silicon gain |
Guitar Pedal X's Stefan Karlsson found the pedal sits very close to the pedal it is modeled on: "Both of those sounds incredible - in fact almost identical in that they share all the same rare killer parts"2. In the same publication's year-end roundup, the Grissom Young Dual Fuzz II took a SILVER placement among the year's new fuzz pedals2.
Parts inside
Guitar Pedal X lists the transistor and component complement, which will interest players who follow germanium-equipped fuzz circuits3:
- Q1-Q2: AC128
- Q3: AC176
- Q4-Q5: 2N2222A
- Q6: 2N3700
- Q7: 2N5088
- D1-D2: 1N4148
- D3: 1N5817
- TR1: 42TL019 transformer
The low current draw of less than 10mA means the pedal is an easy load on any standard pedalboard power supply3.
With only 9 units made, this is a small-edition pedal. Guitar Pedal X's reviewer notes his own unit is handily number 0083.
From the Gemini III to the Dual Fuzz II
Coriolis Effects describes the Grissom Young Dual Fuzz II as "an improved fully variable take on Spaceman's Gemini III"2. The original is the Spaceman Gemini III, a Dual Fuzz Generator from Spaceman Effects1. On the comparison, the reviewer's view is that both it and the original sound almost identical: "Both of those sounds incredible - in fact almost identical in that they share all the same rare killer parts"2.
The Grissom Young Dual Fuzz II lists at $2692. Players interested in the original design it references can read more on the Spaceman Gemini III page, and Coriolis's other fuzz, the Coriolis Effects Face Deluxe, is covered separately.
Videos
Tone Wise Productions
Questions
How many Grissom Young Dual Fuzz II pedals were made?
Guitar Pedal X reports that Devin McNeilly of Coriolis Effects made a total of 9 units of this edition. A first run of 3 units appeared in May 2025, and a second batch was released in September 2025, bringing the edition total to 9. The reviewer's own unit is number 008.
What is the Grissom Young Dual Fuzz II based on?
It is a second take on the Spaceman Gemini III, a dual fuzz generator. Guitar Pedal X describes it as an improved fully variable take on the Gemini III, and found the two sound almost identical because they share the same rare killer parts.
How much current does the Grissom Young Dual Fuzz II draw?
Guitar Pedal X notes that the Grissom Young has a current draw of less than 10mA, which makes it an easy load on any standard pedalboard power supply.
What changed from the original Grissom Young Dual Fuzz?
The II moves to a smaller 125B enclosure with top-mounted jacks, and replaces the original's 3 switchable Gain settings per side with fully variable mini Gain knobs for the germanium and silicon stages.
Who designs Coriolis Effects pedals?
Coriolis Effects pedals are designed by Devin McNeilly. Guitar Pedal X's Stefan Karlsson describes his output as amazing looking and quite exceptional sounding pedals.
What enclosure does the Grissom Young Dual Fuzz II use?
A 125B enclosure. Devin McNeilly's earlier take on the Gemini III, released in 2022, was a larger 1590BB version that was mechanically identical to the original Spaceman pedal.
Sources (3)
- Gemini III: Dual Fuzz Generator, Spaceman Effects
- Guitar Pedal X, Guitar Pedal X, 2025-12-08
- Guitar Pedal X, Guitar Pedal X, 2025-10-06
