Dunlop MXR M87 Bass Compressor

MXR M87 Bass Compressor — Studio Dynamics for the Stage

The MXR M87 Bass Compressor delivers recording-quality compression in a stompbox built for bass. It keeps low-end frequencies tight and clean, covering gentle peak limiting to aggressive squash without losing the instrument's fundamental character. This model is the right choice for bassists who want transparent dynamics control that preserves natural tone while adding consistency and punch.

Constant Headroom Technology and Visual Feedback

What separates this pedal from typical bass compressors is its CHT (Constant Headroom Technology) circuit, delivering clean headroom even with high-output basses. Ten gain-reduction LEDs show exactly how much compression is applied, and an internal switch disables the meter for a darker stage look.

Compression Controls — Dial in Your Dynamics

The control layout covers every core compression parameter a bassist needs.

• Controls: Output, Release, Attack, Input, Ratio — five-knob layout plus a 4-position Ratio selector spanning 4:1 to 20:1
• Attack knob: clockwise speeds up reaction time; counterclockwise slows it for more transient bite
• Release knob: variable range controlling how long reduced gain is held before returning to the original level

Signal Path — True Bypass and Connectivity

Signal integrity is preserved through a hardwired true bypass circuit, so the dry bass tone passes through untouched when off, and side-mounted jacks keep the pedalboard layout tidy.

• True Bypass: Yes — hardwired switching with no buffering or coloration
• Inputs: Jack 6.3 mm TS — standard mono instrument input
• Outputs: Jack 6.3 mm TS — mono output to amp, DI, or next pedal

Power and Construction — Built for the Road

Runs on a single 9V battery or any standard 9V DC adapter, integrating easily into any pedalboard power setup. The housing matches the footprint of the classic MXR Phase 90.

• Battery Powered: Yes (9V) — internal compartment for cable-free operation
• External Power: 9V DC adapter (Dunlop ECB003 or compatible), plus DC Brick, Iso-Brick, and Mini Iso-Brick supplies
• Package Contents: Manual — printed guide explaining the control layout