The Big Joe B-308 CompBox is a compact compressor pedal from Big Joe Stomp Box Company, part of its B-300 Series. Big Joe describes it as an all-analog, true bypass optical compressor that "will help thicken your signal, control signal peaks, and lengthen sustain"1. Optical compressors use a light-sensitive element to control how much the signal is squeezed, a design players often associate with smooth, unobtrusive leveling rather than the harder pumping of some VCA-based circuits.
The list price is $159.95 as of October 20261.
The controls
The CompBox gives you five controls, which is more shaping than the two-knob compressors many players start on. Big Joe's product page lists them as follows1:
| Control | What it is |
|---|---|
| Compression | Sets how much the signal is squeezed |
| Output | Sets the overall level leaving the pedal |
| Attack | Sets how quickly compression engages after you pick |
| Release | Sets how quickly compression lets go as a note decays |
| Range | Selects the operating range for the other settings |
Big Joe says the Range and Compression knobs work together as the fast way into a sound: "It's easy to dial in your settings with a flick of the Range knob and a twist of the Compression knob"1. In practice, the Range knob narrows or widens the window the Compression knob works in, so the same Compression setting behaves differently depending on where Range sits. Attack and Release then shape the feel: fast attack clamps the initial pick transient, while slower release lets sustain ring out before the pedal lets go.
The pedal also carries a status LED so you can see at a glance whether it is engaged1.
Power and connections
The CompBox runs on either a 9V battery or a 9VDC power supply with a 2.1 mm x 5.5 mm barrel connector, polarity negative inside, and the supply is not included1. The center-negative barrel is the same standard used by most modern pedal power supplies and isolated supplies, so it drops onto an existing pedalboard without an adapter. Because it also takes a battery, it works on a board with no power distribution, though the battery has to be bought separately if you go that route.
Connections are a single 6.3 mm mono jack input and a single 6.3 mm mono jack output1, the standard guitar-pedal arrangement. With true bypass switching, your dry signal passes through untouched when the pedal is off1.
At 4.80" x 2.91" x 2.12" and 19oz1, the CompBox sits in the usual compact-pedal size class, taking up about one standard pedalboard slot.
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Questions
Does the Big Joe B-308 CompBox take a 9V battery?
Yes. Big Joe specifies that the CompBox runs on a 9V battery or a 9VDC power supply. The power supply uses a 2.1 mm x 5.5 mm barrel connector with center negative polarity and is not included with the pedal.
Is the Big Joe CompBox true bypass?
Yes. Big Joe describes the B-308 CompBox as an all-analog, true bypass optical compressor, so the signal passes through untouched when the pedal is switched off.
How heavy is the Big Joe B-308 CompBox?
Big Joe lists the CompBox at 19oz. Its dimensions are 4.80 inches long by 2.91 inches wide by 2.12 inches high, a standard compact pedalboard footprint.
Is the Big Joe B-308 analog?
Yes. Big Joe describes the B-308 CompBox as an all-analog optical compressor. Optical compression uses a light-dependent element to control gain reduction, a design associated with smooth, gradual leveling.
Sources (1)
- B-308 COMPBOX, Big Joe Stomp Box Company