Keeley 2-Knob Compressor

History:

Robert Keeley is an engineer and musician from Oklahoma. He worked as a repair technician in electronics stores fixing car stereos, VCRs, and TVs before becoming a college electronics teacher. In 2001 he started Keeley Electronics and had success modifying Tubescreamers and Boss pedals, and his most popular pedal was the Keeley Compressor.

The Keeley Compressor started as a clone of a Ross compressor. Ross was a pedal company that had gone out of business in the 1980s. By 2000, the Ross compressor had become expensive and rare to find. Keeley studied the Ross compressor and listened to what musicians wanted out of a compressor but weren’t getting from the available options. He decided to use metal film 1% tolerance resistors and metal film capacitors, replacing the less precise resistors and ceramic capacitors he thought sounded harsh. He made the pedal true bypass. He was also able to fit the circuit in a smaller enclosure than the Ross.

The pedal became a hit. It was the go-to compressor in Nashville for the ’00s decade. In 2005 Keeley added a 4-knob version of the compressor to the lineup, allowing people to adjust the attack and input sensitivity without having to take apart the pedal and adjust trim pots on the inside. A few years later the cosmetics of the 4-knob version changed. Keeley has since offered the Compressor Pro, the Compressor Plus, the GC-2 Limiting Amplifier, and the Bassist Limiting Amplifier. To distinguish from all of these successors, the original Keeley Compressor is usually referred to as the “2-knob” version.

The Keeley 2-Knob Compressor was discontinued in December 2014 after 13 years on the market and 40,000 pedals made. The CA3080 chip that was part of the Dyna Comp/Ross/Keeley circuit had been out of production since 2004, and by 2014 the supply had become too low to keep making 2-Knob Compressor pedals without altering the circuit. Keeley decided to make new compressors with a different chip and different name, and end production of the classic 2-Knob version. Robert Keeley himself said during a podcast interview that when people talk about the old Keeley 2-Knobs having a certain special sound, he believes them.

Use:

A compressor takes the loudest parts of a signal and limits how loud they can get. With a guitar, the initial pick attack is a loud, quick spike in volume. A compressor pedal can even out the pick attack while keeping a clean guitar tone. Reducing the level of the pick attack also creates the impression that the guitar has more sustain. And overdriven amp or overdrive pedal also evens out pick attack and increases sustain, often making for a more fogiving tone and a more comfortable playing experience. If a guitarist wants that same sensation while keeping a cleaner guitar tone, a compressor pedal can help.

JT often had a compressor as the first pedal in the signal chain. This is common among guitarists, because classic stompbox compressors like the Keeley, Ross, and Dyna Comp don’t work as well if there are high signal levels going into them. If you were to turn on an overdrive or boost pedal into the Keeley compressor, every sound coming from the guitar (soft or loud) would be sent into extreme compression. This usually ends up sounding grating and unnatural. Robert Keeley’s first experience with a compressor was playing into one with a guitar that had high output humbuckers, and he came away from that experience thinking he hated compressors. It wasn’t until years later that he played a Telecaster with lower output pickups through a Fender Deluxe amp with a compressor in the signal chain, and that’s when he fell in love with the sound.

The Keeley 2-Knob compressor has a Sustain knob and a Level knob. The Sustain knob controls how much of the compressor effect happens. Turning it up creates a more compressed sound. The Level knob controls the output volume of the pedal. Turning it up makes it louder (but does not affect the amount of compression the pedal creates).

JT would often set the Keeley 2-Knob Compressor with the Sustain knob around 9 o’clock and the Level knob around 1 o’clock. He would also often use the compressor with his Blue Tele and his Gretsch (both guitars happen to have have lower output pickups).

JT’s Keeley 2-Knob Compressors both had the power jack on top, meaning 2006 or later. One of them was used in a session on June 29, 2009 as seen in a Multi-Platinum Recording DVD. It is likely that the Keeley Compressor from that DVD ended up being the one on his Trailer Trash board or the one on his Pedaltrain-2 board. In the DVD JT starts the session with a Boss CS-3 on the board and the Keeley sits on top of one of his amps at first, then at some point early on he pulls the CS-3 off the board and replaces it with the Keeley for the rest of the session. He may have trying out the Keeley Compressor for that session after having used the Boss CS-3 for many years prior, then liked it enough to buy another so he could have one on his big board and one for his small board.

Specs:

The Keeley 2 Knob Compressor stayed mostly unchanged from its inception until its retirement, but there were some minor changes that can help point toward when the pedal was made. The easiest one is the location of the power jack. The 4-knob compressor was developed in 2005, and the 2-knob compressor transitioned into using the 4-knob circuitboard between December 2005 and February 2005. The 4-knob circuitboard had the power jack on top, whereas the original 2-knob circuitboard had the power jack on the side of the pedal. If the power jack is on the side of the pedal, then the pedal was made before February 2006. If the power jack is on the top of the pedal, it means it was made in January 2006 or later.

The date a Keeley 2-Knob Compressor was made can usually be found on the inside of the pedal. If you take the back off the pedal, the inside of the back will probably have some kind of business card to keep the components on the circuitboard from accidentally touching the metal back of the pedal. Either written on the business card or on the inside of the back of the pedal underneath the business card will be a date. Sometimes this is written as “2-4-06” or “23JUN06”. There are cases where the year was left off (“12-04” written for December 4, 2005).

Keeley Compressors also have a serial number. This was usually stamped on the back of the pedal. To help with dating, here is a list of confirmed serial numbers and dates:

(YYYY/MM/DD) – (Serial #)

2002/04/07 – #130 (stamped 0402130)
2002/04/08 – #140 (stamped 0402140)
2002/05/20 – #179 (stamped 0502179)
2002/05/20 – #192 (stamped 0502192)
2002/06/20 – #202 (stamped 0602202)
2002/08/03 – #321 (stamped 0802321)
2002/08/26 – #373 (stamped 0802373)
2002/10/25 – #474
2003/01/27 – #641
2003/03/08 – #742
2004/18/04 – #2000 (first sold 2004/04/18 at a guitar show, date inside the pedal is unknown)
2005/XX/XX – #2653 (owner claims purchased direct from Keeley in 2005)
2005/12/04 – #5,394
2006/01/13 – #6,446 (date on inside written 13Jan05, but 2005 with this serial, trimpots, and power jack location is impossible so the worker probably forgot it wasn’t 2005 anymore so soon after the new year)
2006/03/23 – #7,008
2006/05/01 – #7,351 (stamped A7351)
2006/05/31 – #7,807 (stamped A7807)
2006/08/15 – #8,763 (stamped A8763)
2007/03/01 – #10,787
2007/04/27 – #11,406
2007/05/01 – #11,441
2007/05/21 – #11,719
2007/07/13 – #12,446
2007/08/02 – #12,608
2007/08/08 – #12,688
2007/11/20 – #13,780
2008/09/15 – #16,903
2008/11/24 – #17,689
2008/12/12 – #17,880
2009/10/20 – #20,575
2009/12/29 – #21,156
2010/03/29 – #22,151
2010/05/10 – #22,581
2011/03/09 – #25,107
2011/08/03 – #26,200
2011/10/04 – #26,708
2011/12/07 – #27,490
2012/01/20 – #28,039
2012/02/09 – #28,637
2012/04/20 – #29,696
2012/05/09 – #30,325
2012/05/15 – #30,156
2013/02/13 – #33,454
2013/04/10 – #34,007
2013/10/17 – #36,278
2013/12/04 – #36,761
2014/12/XX – #40,000, last one made