Keeley Electronics Compressor Pro

  • By Fletcher Stewart @tonereport
  • March 26, 2015

Savor the Flavor or Dish the Squish

The new Compressor Pro from master of the art Robert Keeley, is all about infinite control with minimal head scratching. With a rack-like control set that includes every crucial compression adjustment parameter, Keeley has managed to cram a studio-grade compressor into a robust little stompbox. Everything from soft knee string singing for Johnny Marr-peggios to clawhammer clicking hard knee Knopfler-style limiting is achievable, with every shade of compression in between.

One of the first things I noticed that sets this compressor pedal apart from the pack is the visual reference onboard. This comes in handy (particularly in more subtle applications) for signal sweetening that maintains picking nuance integrity while evening string volumes within chords and adding sustain. The Keeley Compressor Pro allows one to control and monitor the signal digestion process from input to output for the most fine-tunable and piquant tone pumping emissions possible.

A Certain Ratio of Pure Signal Sweetener

One of my favorite features of the KCP is the Threshold control. It functions like a stoplight that lets the unaffected signal through when the corresponding LED is green, and stops the signal information from peaking and decaying when red. When used in conjunction with the ratio control, one can achieve every finite push-pull increment of attack and decay from blooming, to pumping, to constant hard limiting and chicken-pickin’. The attack and release controls will be more familiar to compressor pedal tweakers as they can be interactively set for the perfect amount of holding and releasing of the signal. The former can be set to kick in slower for maintaining picking dynamics and the latter can be set for release times that range from 100 milliseconds to an astonishing three seconds of slow sustaining release. This is great for whipping out the slide and letting the tone glide without choking out.

Though the aforementioned features would be more than enough to keep folks happily tweaking their compression to perfection, Keeley has added three unique features to round off the KCP experience: The gain control can be used as intended to compensate for the volume loss that results from some heavy compression settings, but it is also possible to use the KCP as a 20db booster when the ratio is set to 1:1. Then we have the Knee switch, which brings on an obvious signal squeeze arch in Hard mode, or dynamically enhances the silky sustaining overtones of the guitar in a more transparent fashion when set to Soft. Last but not least, the Auto switch can disengage the attack and release controls and automatically find the perfect enhancement balance based on the frequencies coming into the unit…pure genius. 

What we like: Keeley has long been the word in top shelf compression pedals and this Compressor Pro is the monument atop the market mountain in this category. It has the ability to be as simple or as comprehensive as the user needs, and can be used for any instrument, vocal or studio application. There are a million ways in which this machine could prove useful.

Concerns: Those in the know can ignore this statement, but compression newbies might scoff at a comp pedal that costs three big ones. But, this is more like a studio-grade high-performance rack unit that fits on a pedalboard. When you take a peek at some examples in the rack analog compressor market, you will quickly realize just how affordable this unit is considering it can hang with (and even surpass) some vintage gear that fetches over twice the price.

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  1. Robert Keeley

    Thanks for the very nice review.  I noticed that we had the Release Control labeled a little wrong in the picture.
    ATTACK Control – Attack Times between 0.15ms and 150ms.  Controls the time it takes for the Comp Pro to start compressing.

    RELEASE Control – Release Times between 0.1s to 3s.  Controls the time before the Comp Pro releases or stops compression .