The Effectrode PC-2A is a photo-optical tube compressor pedal, built in a stompbox-sized steel chassis but designed around a studio classic: the Teletronix LA-2A. MusicRadar describes it as "inspired by one of the finest compressors ever made, the legendary LA-2A studio compressor"1. Where most pedal compressors use a light-dependent resistor and an LED or lamp driven by op-amp circuitry, the PC-2A keeps the whole signal path analog and valve-based, using a 6112 dual triode, a subminiature valve originally made as a proximity trigger in WW2 anti-aircraft shells1.
Effectrode began shipping the PC-2A in July 2010, priced at $359 direct from the company's website2. Its designer is Phil Taylor, whom MusicRadar calls the company's "effects scientist," based in the UK1.
A valve compressor modeled on the LA-2A
The Teletronix LA-2A is a studio optical compressor rack unit with two knobs, Gain and Peak Reduction, plus a switch for compression or limiting4. The PC-2A carries that layout over into a pedal: two knobs, Peak Reduction and Gain, and a Limit switch that changes whether the pedal works as a compressor or a limiter2. It is, in MusicRadar's words, "just slightly larger than your average stompbox," with all connections on the rear edge to save pedalboard space1.
The compression itself is optical, like the LA-2A's. According to the manual as reported by MusicRadar, the photocell has a natural two-stage decay shape: after 40 to 80 milliseconds it reaches half of its initial resistance, and full recovery can take up to several seconds depending on signal intensity1. In standard compression mode, the release is barely noticeable1.
The controls: Peak Reduction, Gain and Limit/Compress
| Control | What it does |
|---|---|
| Peak Reduction | Sets both the ratio (the amount of compression) and the threshold (the point at which the input gain triggers the compressor)1 |
| Gain | Boosts the signal to make up for the effect of compression; can also add extra valve boost1 |
| Limit/Compress switch | Changes the mode the pedal works in, either as a compressor or a limiter12 |
The Peak Reduction knob doing double duty is the LA-2A approach: one knob sets how hard the compressor works rather than separating ratio and threshold as many pedal compressors do. The Gain knob is the make-up stage, but it is also the pedal's route to pushing an amp harder, since it can add extra valve boost on top of the compression1.
Compress versus limit mode
The two modes change the character of the effect considerably:
- Compress mode provides richness to bring out tone, with a lower, less noticeable ratio12.
- Limiter mode runs a much higher and more noticeable compression ratio, creating heavy compression for that "squashed" effect12.
MusicRadar found limiter mode "an even warmer, smoother sound than the other mode" for times when you need serious squashing, though the reviewer also judged the Limiter setting "probably going to be less useful for most guitarists"1.
Power and practicalities
The PC-2A cannot run on a battery. The voltages required to drive the valves are beyond what a battery can deliver, so the pedal comes with a 12-volt power supply1. This rules out running it from a standard daisy chain supply as well.
What reviewers said
MusicRadar's review was positive across the board. On sound, the reviewer found the PC-2A has "a recognisable voice, adding smoothness and warmth," with a very fast attack in keeping with the LA-2A heritage1. It was also praised for what it is not:
"The PC-2A isn't one of the lazy, squishy compressors that we've seen from several 'boutique' builders... it's far more crisp and precise, but it does add a wonderful warmth to your tone, as well as obvious audiophile quality."
The overall verdict was short: "Audibly high quality compression in a stompbox," with "nothing to dislike," and the reviewer singled out clean-toned parts as where the pedal is especially worthwhile1. The PC-2A also appeared in That Pedal Show's roundup of six high quality pedal compressors in March 20165.
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Questions
Can the Effectrode PC-2A run on a battery?
No. The voltages required to drive the valves are more than a battery can deliver, so the pedal ships with a 12-volt power supply instead. Plan on a dedicated outlet on your power brick rather than a battery or a standard 9V daisy chain.
What tube does the Effectrode PC-2A use?
It uses a 6112 dual triode, a tiny subminiature valve that was originally made as a proximity trigger in WW2 anti-aircraft shells. Effectrode's designer Phil Taylor builds the compressor around this valve for its analog signal path.
What is the difference between compress and limit mode on the PC-2A?
In compress mode the pedal works as a standard compressor with a lower, less noticeable ratio, adding richness and bringing out tone. In limiter mode the compression ratio is much higher and more noticeable, producing heavy compression for a squashed effect.
Can the PC-2A be used as a clean boost?
Partly. The Gain knob is there primarily to make up the level lost to compression, but MusicRadar notes it can also be used to add extra valve boost, so it can push your amp harder on top of the compression.
How much does the Effectrode PC-2A cost?
When Effectrode began shipping the PC-2A in July 2010, No Treble reported a price of $359 direct from the Effectrode website. That is a 2010 figure; check Effectrode's current product page for today's price.
Sources (5)
- Effectrode PC-2A Compressor review, MusicRadar, 2011-03-02
- Gear Watch: Effectrode PC-2A Photo-optical Compressor Pedal, No Treble (notreble.com), 2010-07-12
- PC-2A Tube Compressor, Effectrode, 2026-08-18
- New Pedal: Spaceman Ixion Optical Compressor, Delicious Audio, 2023-02-28
- Six Quality Compressors To Send You Squishy, That Pedal Show, 2016-03-18
