The Sushi Box FX Space Heater is a simple 12AX7 tube preamp pedal, designed by Sushi Box FX to give tube warmth with a little bit of breakup in a compact package. It is a high output circuit, and the maker notes it will push your amp HARD. The pedal is now archived, so it is no longer in current production.1
Circuit lineage: Particle Accelerator and the Alembic F-2B
Sushi Box FX describes the Space Heater's gainstages as set up similarly to the Particle Accelerator, so there is some shared DNA with the Alembic F-2B.1 The F-2B is a tube preamp that Premier Guitar describes as "known for its warm yet articulate character."2 For a player, that lineage places the Space Heater among preamps that aim for a warm, articulate tube character rather than heavy distortion, with breakup arriving as a light touch rather than the main event.
Controls and power
The layout is minimal: a Gain control and a Level control, with a single footswitch that bypasses the pedal.1
Power is where the Space Heater differs from most pedals on a board. It runs on 9-12vdc with center-negative polarity, like most guitar pedals, but the tube's heater means the current draw is far higher than a typical solid state pedal: 500mA at 9vdc during warmup, settling to 250mA at 9vdc after warmup.1
Because of the warmup draw, a small supply or a shared daisy chain sized for ordinary pedals may not be able to power the Space Heater at switch-on. Give it its own outlet on a supply with enough current headroom.
Related Sushi Box FX preamps
Sushi Box FX has built a range of tube preamp pedals around similar ideas, including the Underground Accelerator, Venus Z, Finally v3 and Dr. Wattson X, alongside the Space Heater's sibling designs in the same preamp family.
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Guillaume Tirard
Questions
What tube does the Sushi Box FX Space Heater use?
The Space Heater uses a single 12AX7 tube. That tube is what gives the pedal its tube warmth and breakup, and it is also why the pedal draws more current than a typical solid state pedal, especially during warmup.
Is the Space Heater still in production?
No. Sushi Box FX lists the Space Heater as Archived on its product page, meaning it is no longer in current production. It may still be found secondhand or in dealer stock.
Why does the Space Heater draw more current at startup?
Like any tube circuit, the 12AX7 needs its heater to reach operating temperature before the circuit works normally. Sushi Box FX specifies 500mA at 9V during warmup, dropping to 250mA at 9V after warmup, so a supply sized for ordinary pedals may not be enough at power-on.
Is the Space Heater power polarity center-negative?
Yes. Sushi Box FX specifies center-negative polarity, like most guitar pedals, running on 9 to 12V DC.
What is the Space Heater based on?
Sushi Box FX says the gainstages are set up similarly to the Particle Accelerator, so there is shared DNA with the Alembic F-2B, a tube preamp Premier Guitar describes as known for its warm yet articulate character.
Sources (2)
- Space Heater, Sushi Box FX
- Dawner Prince Electronics Introduces Eclipsa Triple Rotary, Premier Guitar, 2026-05-04
David Gilmour
