The Keeley GC-2 Limiting Amplifier is a compressor pedal from Keeley Electronics, released in late 2014. It is a limiting amplifier in stompbox form: a studio-style compressor circuit that Keeley says delivers studio quality compression, which Delicious Audio described as meaning the effect is uncolored and transparent1. The circuit is based on the THAT Corporation 4320 processor, a high-fidelity dynamics chip, and was borrowed from Keeley's Bassist Limiting Amplifier, a compressor designed for bass players12.
The pedal is hand-built in the U.S. and comes in a black case with minimal white and red graphics41. THAT Corporation's own press release about the design says Robert Keeley chose the THAT4320 Analog Engine for the GC-2 and the Bassist Compressor, and that these 100% hand-built pedals contain unique and modern circuits that deliver studio quality compression3.
The controls: Compression, Threshold and Gain
The GC-2 keeps things simple with only three knobs: Compression, Threshold and Gain, plus a Threshold indicator41. Here is what each control does, based on how the same controls are described on the Bassist circuit the GC-2 borrows:
| Control | What it does |
|---|---|
| Compression | Sets the compression ratio, from 1:1 (no compression) to infinity, where the pedal functions as a limiter2 |
| Threshold | Sets the input level at which compression kicks in1 |
| Gain | Adjusts the output level; it can compensate for compression reduction or be turned up higher to work as a boost2 |
| Threshold indicator | Shows when the signal crosses the threshold and the circuit is compressing4 |
The compression range runs from 1:1 to 1:Infinity, so at one extreme the pedal leaves the signal alone and at the other it acts purely as a limiter, clamping peaks rather than gently evening out dynamics4. Vintage Guitar also noted a boost of up to 30dB available from the Gain control4.
A detail players used to fixed-attack compressors should know: the attack and release response varies according to the signal level and the player's style, rather than being locked to set times1.
The GC-2's compression and limiting technology was borrowed from Keeley's Bassist Limiting Amplifier, a compressor Robert Keeley designed specifically for bass players12. The two pedals share the same THAT4320-based circuit3.
What it works with
Although it sits in a guitar pedal enclosure, the GC-2 is not limited to guitar. Delicious Audio reported that its musicality and low noise make it ideal not only for guitar and bass but also for keyboards and drum machines1. Bass players looking at the same circuit family can read more about bass pedals generally, or about the Bassist itself.
What reviewers said
Pete Thorn demoed the GC-2 on his YouTube channel when it was new, calling it a limiting amplifier or compressor pedal and finding that it made for a nice lead guitar tone with sustain, without an overdrive lead tone5:
"it really makes for a nice beautiful lead guitar tone everything's so much easier to play with the compressor too"
His demo covers the pedal's behavior on lead playing, showing how the compression adds sustain and evens out the attack without pushing the amp into overdrive5.
Where it sits in the Keeley compressor line
The GC-2 is one of a family of Keeley compressors. Later releases include the Keeley Compressor Plus, the two-knob Keeley Compressor Mini, and the 25th-anniversary Keeley Compressor Plus Germanium. Compared with those, the GC-2's distinguishing feature is its studio-style limiting amplifier circuit with the wide 1:1 to 1:Infinity compression range and Threshold indicator, aimed at players who want transparent control rather than a colored squeeze.
Videos
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Questions
Does the Keeley GC-2 have true bypass?
Yes. Vintage Guitar reported that the GC-2 includes true-bypass switching, so with the pedal off the signal passes through without the circuit in the path.
Where is the Keeley GC-2 made?
The GC-2 is hand-built in the U.S. by Keeley Electronics, according to Vintage Guitar's coverage of the pedal at its release.
Can the GC-2 Limiting Amplifier be used with bass and keyboards?
Yes. Delicious Audio reported that its musicality and low noise make it ideal not only for guitar and bass but also for keyboards and drum machines. Its circuit was borrowed from Keeley's Bassist Limiting Amplifier, a compressor designed for bass players.
What is the compression range of the Keeley GC-2?
The compression can be set from 1:1, which is no compression, to infinity, where the pedal functions as a limiter. Vintage Guitar describes this as a range of compression from 1:1 to 1:Infinity.
What does the Threshold indicator on the GC-2 show?
The GC-2 has controls for Compression, Threshold, Gain and a Threshold indicator, as reported by Vintage Guitar. The indicator shows when the input signal has crossed the threshold level and the circuit is actively compressing.
Sources (5)
- New Pedals: Keeley GC-2 Limiting Amplifier, Delicious Audio, 2014-12-15
- Keeley Bassist Compressor Review, Bass Musician Magazine, 2015-01-08
- Keeley Selects THAT4320, THAT Corporation, 2014-12-30
- Keeley Offers GC-2 Limiting Amplifier Pedal, Vintage Guitar magazine, 2014-11-27
- Keeley GC2 Compressor/Limiter, demo by Pete Thorn/Vintage King, YouTube (Pete Thorn channel), 2014-11-16
