Boss CS-3 Guitar Effect

Boss CS-3 Compression Sustainer — Classic Analog Dynamics Pedal

The Boss CS-3 Compression Sustainer is a compact analog stompbox pedal that evens out volume swings and extends note sustain on electric guitar and bass. In continuous production since 1986, this blue BOSS classic delivers natural-sounding compression without added distortion. A high-performance VCA circuit reduces louder signals while boosting softer ones for balanced, articulate response across rhythm and lead playing.

What Sets the CS-3 Apart

A dedicated Tone knob adds an EQ layer to the compressed signal — higher settings brighten the treble for cutting funk rhythms, while lower settings soften the highs for jazz voicing. The buffered bypass design keeps the signal stable through long cable chains, and the low-noise VCA architecture ensures transparent operation at high Sustain settings.

Four-Knob Dynamics Control

Four knobs give players direct control over every dimension of the compression effect.

• Sustain knob: compression ratio control — sets how aggressively dynamics are evened out and how long notes ring.
• Attack knob: attack-speed control — clockwise preserves string attack; counterclockwise softens transients.
• Tone knob: high-frequency EQ — shapes brightness for cutting or mellow voicing.
• Level knob: output volume — balances output with the bypassed signal.

Signal Path and Bypass

Standard 1/4-inch TS connections make the CS-3 compatible with virtually any guitar or bass rig.

• Input: Jack 6.3 mm TS — 1 M ohm impedance preserves pickup tone.
• Output: Jack 6.3 mm TS — 1 k ohm impedance drives long cables cleanly.
• Bypass: Buffered bypass — maintains signal integrity through complex pedal chains.

Power, Dimensions, and Build

Power comes from a single 9V battery or any BOSS PSA-series AC adapter.

• Power supply: 9V battery or PSA-series adapter — approximately 26 hours of alkaline battery life.
• Current draw: 20 mA — low draw for battery-powered gigs.
• Dimensions: 73 × 129 × 59 mm — fits standard compact-pedal board layouts.
• Weight: 380 g — light enough for travel boards.