Boss ST-2 Power Stack Guitar Pedal

An authentic distortion stompbox engineered to replicate the dynamic response and tonal characteristics of a traditional tube-driven stack amplifier.

As part of BOSS’s ongoing development of high-performance signal processors, the ST-2 Power Stack draws upon extensive research into benchmark tube amplifier circuitry. The design intent is to provide players with the dynamic power and harmonic complexity of a cranked stack without the associated volume limitations, bridging the gap between traditional preamp topology and modern pedalboard convenience.

The unit is housed in a rugged, road-proven metal chassis measuring 73 × 129 × 59 mm and weighing 410 g. It features standard 1/4-inch mono input and output interfaces, with an input impedance of 1 M ohm and an output impedance of 1 k ohm. Power is managed via a standard 9 V DC architecture, supporting either a 9 V alkaline battery or an optional PSA-series AC adapter, with an internal current draw of 65 mA.

Key Features

• Delivers classic stack-amplifier sounds ranging from warm vintage crunch to modern high-gain distortion.

• Incorporates a multi-stage SOUND knob that simultaneously adjusts gain levels and harmonic character for rapid tone shaping.

• Maintains high signal clarity and touch sensitivity, responding accurately to guitar volume changes and picking articulation.

• Features a focused, defined low-end response designed to prevent muddy lower frequencies common in high-gain stompboxes.

• Equipped with a dedicated two-band EQ featuring independent BASS and TREBLE controls for precise output tailoring.

• Built within standard BOSS compact pedal dimensions for seamless integration onto existing pedalboards.

• Utilizes a reliable buffered bypass configuration to maintain signal integrity across long cable runs.

• Includes clear visual monitoring via a dedicated check indicator for battery status.

• Powered flexibly via a 9 V battery or external DC power supply.

Frequently Asked Questions What does the SOUND knob on the BOSS ST-2 do?

The SOUND knob is a dual-function control that simultaneously alters the pedal's gain level and overall tonal character. Rotating it transitions the signal smoothly from a mild vintage crunch to a full, high-gain modern distortion stack sound.

Is the BOSS ST-2 analog or digital?

The BOSS ST-2 uses digital signal processing (DSP) based on Roland and BOSS amp-modeling research to emulate the dynamic response, compression characteristics, and harmonic feel of a tube-driven stack amplifier.

How do I power the BOSS ST-2?

The pedal can be powered using a standard 9V battery (alkaline recommended due to its 65 mA current draw) or an optional 9V DC center-negative AC adapter (such as the BOSS PSA series).

Can the BOSS ST-2 clean up using my guitar's volume knob?

Yes. The pedal is specifically engineered to mirror the dynamic behavior of a real tube amplifier. Rolling back your guitar’s volume knob or altering your picking attack lowers the gain amount while keeping the tone clear and expressive.