Keeley Electronics · Compression

Keeley Compressor Plus Settings Guide

The Keeley Compressor Plus is a classic two-knob OTA (Operational Transconductance Amplifier) compressor — the same circuit type as the Ross Compressor and original MXR DynaComp, but refined by Robert Keeley with lower noise floor and improved tone. Sustain and Level are the only controls, making it one of the simplest high-quality compressors available. A Blend control was later added in the "Plus" version for parallel compression.

The best Keeley Compressor Plus settings start with: Sustain at 5/10, Level at 6/10, Blend at 7/10. Adjust from there based on your amp, guitar, and room volume. For Country (squash): Sustain 8/10, Level 6/10, Blend 9/10.

What Each Control Does

Sustain
Light
Heavy
Compression amount / threshold
Level
Off
Loud
Output make-up gain
Blend
Dry
Wet
Parallel compression blend (Plus version)

Recommended Starting Settings

Safe starting positions for any style. Adjust from here based on your amp and room.

5
Sustain
6
Level
7
Blend

All values on a 0–10 scale. These are starting points — fine-tune by ear.

Settings by Genre

Country (squash)
Sustain8
Level6
Blend9

High Sustain for classic OTA squash — the Keeley at Sustain 8 produces significant gain reduction with the characteristic OTA attack/release character that defines classic country compression. Blend at 9 means the compressed signal dominates. This is the "snap and squash" compression that makes chicken-picking techniques sound tighter.

Clean (subtle)
Sustain4
Level6
Blend5

Moderate Sustain with equal Blend for parallel compression — the Blend at 5 mixes 50% dry with 50% compressed, producing a naturalistic dynamic control. The OTA compression at Sustain 4 is relatively light; the parallel blend prevents the squash from feeling mechanical.

Blues (sustain)
Sustain6
Level6
Blend8

Moderate-high Sustain for lead sustain enhancement. Blend at 8 means the compressed signal is dominant. The OTA character at Sustain 6 lets the initial pick transient through before clamping — producing the "bloom" effect on lead notes that sustains smoothly.

Tips & Common Mistakes

  • The OTA compressor circuit (used in Ross, DynaComp, Keeley) has a specific dynamic character — the attack is not fully adjustable, and it responds faster than optical compressors but slower than FET designs. This gives OTA compression its characteristic "snap" where the initial transient passes through briefly before the compressor engages.
  • Robert Keeley's primary modification to the Ross/DynaComp circuit was improving the noise floor — the original designs are notoriously noisy at higher Sustain settings. The Keeley Compressor Plus is significantly quieter at equivalent compression levels.

Keeley Compressor Plus — Common Questions

Best starting settings for Keeley Compressor Plus: Sustain at 5/10, Level at 6/10, Blend at 7/10. Adjust from there based on your guitar, room, and playing style.

For Country (squash): Sustain 8/10, Level 6/10, Blend 9/10. High Sustain for classic OTA squash — the Keeley at Sustain 8 produces significant gain reduction with the characteristic OTA attack/release character that defines classic country compression. Blend at 9 means the compressed signal dominates. This is the "snap and squash" compression that makes chicken-picking techniques sound tighter.

For Clean (subtle): Sustain 4/10, Level 6/10, Blend 5/10. Moderate Sustain with equal Blend for parallel compression — the Blend at 5 mixes 50% dry with 50% compressed, producing a naturalistic dynamic control. The OTA compression at Sustain 4 is relatively light; the parallel blend prevents the squash from feeling mechanical.

Sustain: Compression amount / threshold (Light to Heavy). Level: Output make-up gain (Off to Loud). Blend: Parallel compression blend (Plus version) (Dry to Wet)

The OTA compressor circuit (used in Ross, DynaComp, Keeley) has a specific dynamic character — the attack is not fully adjustable, and it responds faster than optical compressors but slower than FET designs. This gives OTA compression its characteristic "snap" where the initial transient passes through briefly before the compressor engages. Robert Keeley's primary modification to the Ross/DynaComp circuit was improving the noise floor — the original designs are notoriously noisy at higher Sustain settings. The Keeley Compressor Plus is significantly quieter at equivalent compression levels.

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