The [redacted b] from Sushi Box FX is an analog tube preamp and DI pedal for bass. It runs a 6SL7 tube in the preamp and is designed, in the maker's words, to capture "the warm, vintage tone of golden-era tube bass amplifiers used in major recording studios from the 60s to today"1. It sits on a board like a normal pedal but can also replace the front end of an amp entirely: one output feeds your amplifier, the other feeds the desk.
What it does to your signal
The tone shaping comes from two things. First, a standard Baxandall/James two-band tonestack, the broad shelving EQ found on classic bass and hi-fi designs, which gives wide control over bass and treble rather than narrow midrange sweeps1. Second, a switchable high-pass filter (HPF) that shaves off low frequencies below 90Hz at a rate of -6dB per octave, useful for tightening up a mix or keeping a PA from fighting subsonic rumble1.
Outputs and routing
The [redacted b] is built around two independent outputs, and the routing is more flexible than most preamp pedals1:
- Unbalanced 1/4-inch output for your amplifier, with an inline buffer to prevent interference between the two outputs and let them act independently1
- Balanced XLR D.I. output for a mixer or audio interface1
- Separate volume control for the XLR, on the side of the pedal, adjustable independent of the 1/4-inch output1
- "Source select" switch on each output, so either output can carry the preamp signal or the original "dry" input signal, operating independently1
That last feature is the practical one: you can send your amp the full preamp tone while the front-of-house engineer gets the dry bass, or the other way around, without re-patching1.
Power and size
As a tube pedal, the [redacted b] requires a high amount of current to operate correctly. Sushi Box FX recommends a 9-12VDC power supply capable of delivering at least 600mA1. A standard 100mA daisy-chain output will not run it, and a battery is not an option.
The enclosure measures 4.7 in x 3.7 in x 1.5 in (120 mm x 94 mm x 38 mm)1. When ordering, the pedal is offered with a choice of "Include Power Supply? Yes, No", so you can add a suitable supply at purchase or use your own1.
Where it sits in the Sushi Box FX range
Sushi Box FX builds a line of tube preamp pedals, and the [redacted b] is one of several bass-oriented designs. The maker's The Watt is another tube pedal in the range2, and the redacted ii is a related model in the same family. For how this kind of pedal fits a rig more broadly, see the site's Preamp Pedals page.
If you want to hear the [redacted b] before forming your own view, Sushi Box FX publishes Guitar Demos and Bass Demos soundcloud sets on the product page1.
Videos
Bass Gear Demos by Dawghouse
Questions
What tube does the Sushi Box FX [redacted b] use?
The [redacted b] uses a 6SL7 for the preamp, according to Sushi Box FX. The 6SL7 is a dual triode tube long associated with vintage amplifier front ends, and it is the tube the maker chose to shape the pedal's core gain and tone character. Because it is a real tube circuit, the pedal draws a high amount of current and needs a supply that can deliver at least 600mA.
Does the [redacted b] have an XLR DI output?
Yes. The pedal has both an unbalanced 1/4-inch output and a balanced XLR D.I. output, and each one has its own volume control. The XLR level is set by a separate control on the side of the pedal, so it can be adjusted independently of the 1/4-inch output going to your amp.
What does the high-pass filter on the [redacted b] do?
The [redacted b] has a switchable high-pass filter that shaves off low frequencies below 90Hz at a rate of -6dB per octave. In practice, that trims the subsonic rumble that muddies a mix or overloads a PA, while leaving the fundamental and midrange of the bass intact. You switch it on or off depending on the room and the material.
Does the [redacted b] come with a power supply?
Sushi Box FX offers the pedal with or without a power supply, as a Yes or No option when ordering. Either way, the pedal needs a 9-12VDC supply capable of delivering at least 600mA, because the tube circuit requires a high amount of current to operate correctly.
How big is the Sushi Box FX [redacted b]?
The enclosure measures 4.7 inches by 3.7 inches by 1.5 inches, or 120mm by 94mm by 38mm. That is a compact footprint for a tube preamp, though the tube and its heater are why the pedal pulls more current than a typical solid-state pedal.
Is the Sushi Box FX [redacted b] analog or digital?
It is an analog tube pedal. There is no modeling or digital processing in the signal path: the preamp runs on a 6SL7 tube, and the tone shaping is done with a Baxandall/James two-band tonestack and a switchable high-pass filter.
Sources (2)
- redacted b, Sushi Box FX
- The Watt, Sushi Box FX
