1982 MXR Stereo Chorus

Model Description:

The bright yellow large‑box, mains‑powered MXR Innovations Stereo Chorus (MX‑134) was released in the mid‑1970s shortly before its little brother the similarly hued single‑control MXR Micro Chorus. Only the later pedals from c.1982‑1984 had an LED status indicator. Analogue chorus was developed in an attempt to emulate studio ‘automatic double tracking’ (ADT) by adding a very short delay to the original signal. It also aspired to imitate the rotating Leslie speakers of the era by slightly modulating the pitch to create a pseudo‑Doppler effect. Both objectives were achieved with a greater or lesser degree of success. The analogue chorus effect was pioneered by Japanese company Roland from the early 1970s and was introduced in pedal form by the BOSS CE‑1 Chorus Ensemble, derived from the Roland JC‑120 transistor combo amp. After the launch, other effect companies jumped on the bandwagon as demand grew rapidly. By the late 1980s the use of the chorus effect had become oversaturated and perceived as clichéd and ‘old hat’. Now, in the 21st Century, chorus has seen a rejuvenation with many sophisticated chorus solutions hitting the market, both from mass market producers and from small boutique manufacturers. Arguably, other than the more compact BOSS CE‑2 Chorus, the leader of the pack at the time was the Electro‑Harmonix Small Clone, popularised by the late Kurt Cobain of Nirvana. For tech heads out there, the core component of the MXR Stereo Chorus is the Panasonic MN3008 low noise ‘bucket brigade device’ (BBD) delay chip. The large box MXRs are generally overlooked in favour of the smaller versions, probably for convenience, simplicity and price. This means that the larger versions tend to be less common and good ones tend to be quite pricey on the vintage market, although the patient buyer can often pick one up at reasonable price. The MXR Stereo Chorus has been reissued by Dunlop (with 5 controls) and is arguably more flexible but less engaging than the original.

Pedal Description:

This, here, is a large 1982 MXR Stereo Chorus in all its vivid yellow glory. Quite something isn’t it? I was actually looking for the smaller MXR Micro Chorus when this one came up and it was an opportunity not to be missed. The controls are relatively simple with familiar ‘Width’ and ‘Speed’ knobs to control intensity and rate. The ‘Manual’ control is very subtle in that it controls the delay time between the original signal and chorus, which gives an understated shift in tone, harmonics and dynamics, which is best heard through the true stereo outputs. Just because it can be used in stereo, doesn’t mean it has to be. It can also be used in mono, with each output producing a slightly different signal, very much like the Ibanez CS9 Stereo Chorus. Simply pick your preferred sound from one, other or both outputs and play. One might wish for a ‘blend’ control to fine tune the mix of the dry and wet signals and the LED status light of later versions would be a boon. Otherwise, this pedal is effortless to use. One might wonder why it needs such a large enclosure and mains power. The previous owner who had it from new said that it has seen some occasional stage use, yet it has been well looked after and is still in excellent condition with a few very minor paint chips here and there. It also sounds absolutely fabulous. Unusually for me, I actually prefer the more versatile MXR effects, not because I like fiddling with controls in search of a ‘sweet spot’ but because I just favour the more complex and clearly defined sounds that emanate from them. There really is nothing to compete with the comfortingly warm, lush, sweet modulated vibes of a good vintage analogue chorus, although I have to say that I generally prefer flangers. Does the chorus effect sound like ADT or a Leslie cabinet? Nope, nothing like it but it does sound great in its own right and in my view, that’s how it should be judged. Altogether now…


  • Made in Rochester, New York, U.S.A. in 1982
  • The ‘Manual’ knob controls the delay time between the original and effected signal
  • The ‘Width’ knob controls the strength and depth of the effect
  • The ‘Speed’ knob controls the rate at which the chorus effect cycles
  • Standard footswitch turns the effect on and off
  • Standard ¼” single mono input and a pair of stereo output jack sockets
  • MXR ‘block’ logo
  • No LED status indicator
  • 240V UK mains power supply input only
  • No box or instruction manual

Detail Gallery:

← Return to ‘effects’ page

Like it? Why not share it?