The Boss CS-2 Compression Sustainer is a compressor pedal first released in 1981, designed to even out a guitar's dynamics and hold notes longer. It sits in the compressor family alongside the earlier Boss CS-1 and the later CS-3 Compressor/Sustainer.
What it does and how it works
The CS-2 compresses the incoming signal so quiet notes come up and loud notes come down, which extends sustain and evens out playing dynamics. Its most significant technical step came in how it does that. "While the CS-1 used an optical detector circuit, the next-generation CS-2 introduced a VCA for faster response," Boss explains. A VCA, or voltage-controlled amplifier, is the gain-changing element at the heart of the compressor, and the faster response means the pedal can react more quickly to changes in playing level14.
Boss also points to a sonic byproduct of that design: "subtle distortion in the VCA circuitry adds natural richness and character" to the compressed signal5.
Controls
| Control | What it does |
|---|---|
| Level | Sets the output level6 |
| Attack | Adjusts the response to suit personal touch and different music styles7 |
| Sustain | Sets the amount of compression and sustain6 |
The Attack knob is the control that sets the CS-2 apart from its predecessors. Boss describes it as adjusting "the response to suit your personal touch and different music styles"7. Aion FX, which studied the circuit for its own recreation project, notes that "they added an Attack knob, which technically controls the release of the compressor circuit, but the name stuck"6. In other words, despite the name, it shapes how the compression lets go rather than how quickly it clamps down.
History and where to find it today
The original CS-2 pedal is long out of production, but the circuit has lived on in two ways2:
- Boss PX-1 Model Pass: In May 2026, Boss added the CS-2 as a downloadable Model for the PX-1 Plugout FX, described by Guitar Pedal X as "a second compressor Model added - the CS-2 Compression Sustainer (1981-89)"2.
- Inspired designs: The circuit has influenced later builders. Guitar Pedal X describes the Olinthus Pillbug FET Compressor, launched in December 2025, as inspired by the Boss CS-2 and Ross Compressor3.
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Questions
What is the Boss CS-2 Compression Sustainer?
The CS-2 is a compressor pedal from Boss, first released in 1981, that compresses the guitar signal and sustains notes longer. It uses a VCA (voltage-controlled amplifier) for faster response than the earlier CS-1's optical detector circuit, and its three knobs are Level, Attack and Sustain. Boss describes the subtle distortion in the VCA circuitry as adding natural richness and character.
How does the CS-2 differ from the CS-1?
The CS-1 used an optical detector circuit, while the CS-2 introduced a VCA for faster response. The CS-2 also added an Attack knob, which Aion FX notes technically controls the release of the compressor circuit, letting players adjust the response to suit their touch and musical style.
Sources (7)
- BOSS PX-1 Plugout FX: CS-2, PW-2, and XT-2 Model Passes, BOSS (articles.boss.info), 2026-06-17
- Guitar Pedal X, Guitar Pedal X, 2026-05-21
- Guitar Pedal X, Guitar Pedal X, 2025-12-11
- BOSS - PX-1 | Plugout FX, BOSS (boss.info)
- BOSS - PX-1 | Plugout FX, BOSS (boss.info)
- Aurora Compressor / Sustainer, Aion FX, 2018-06-30
- BOSS - PX-1 | Plugout FX, BOSS (www.boss.info)
David Gilmour
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