Reference Series (1973–1984)

MXR M-101 Phase 90
(1975-1981)

MXR M-104 Distortion + (1979)

MXR M-105 Phase 45
(1975-1981)

The first MXR effects pedal was the M-101 MXR Phase 90 phaser. The Phase 90 was used on the first two Van Halen albums.^[4] The MXR Phase 45, followed, as well as a programmable version, the Phase 100. Like other pedals of the time, MXR pedals prior to 1981 did not have LEDs, A/C adaptor jacks, or true-bypass switching.

The first period is known as the "Script period," in reference to the cursive logo on the case. The earliest script logo pedals were made in the basement shop of the MXR founders^[5] and the logos were silk screened. These very first pedals can be identified by a slightly larger font "MXR" on the case.

The "Box Logo Period 1" began around 1975-6 and lasted until 1981, and is named for the writing on the front of the box. The "Box logo period 2" started in early 1981 and went until 1984, when the company stopped making pedals. The main change in this era was the addition of LEDs and A/C adaptor jacks. These pedals used 1/8" power jacks and had exactly the same circuit board as their pre-1981 box logo brothers.

Commande Series (1981–1984)

In 1981, MXR introduced the Commande Series, a line of plastic (Lexan polycarbonate) pedals. Their design departed from the Reference Series in several respects. The input, output and power jacks were all moved to the top of the case to allow a tighter grouping on the floor, or pedal board.

• M-161 MXR Phaser
• M-162 MXR Preamp
• M-163 MXR Sustain
• M-164 MXR Overdrive
• M-166 MXR Time Delay
• M-167 MXR Stereo Chorus
• M-168 MXR Stereo Flanger

2000 Series (1982–1984)

The Series 2000 was a complete rework of the Reference and Commande lines of pedals. They were higher quality pedals, with electronic FET switching and dual LED indicators. They had a contoured, all-metal chassis and an easily removable battery. They had a fully rubberized bottom and were remote-controllable. Most of the pedals had dual outputs with distinctly different sounds.

The MXR Series 2000 sported six models. These original pedals in the series included the Dyna Comp, Distortion +, Phaser, Stereo Chorus, Stereo Flanger and Time Delay. In late 1983 MXR announced a digital sound effects pedal generator simply known as the Junior. The Junior was released in early 1984 and was added to the other six pedals in the Series 2000 line. The Junior boasted four sound effects: a laser, a clap, a snare and a high hat. The effects were samples stored on a replaceable 24-pin ROM chip that was produced by MXR. MXR continued to manufacture most of the Reference, Commande and 2000 Series pedals until they closed down in 1984.

MXR Rackmount Effects

MXR M-124 Dual 15-Band Graphic EQ
MXR M-131 Pitch Transposer Display
MXR M-129 Pitch Transposer
MXR M-126 Flanger/Doubler

MXR also had a line of professional rackmount effects used by the likes of David Gilmour,^[6] Stuart Adamson and Mike Rutherford. The first product introduced was the Digital Delay, which had delay times from 0.08ms to 320ms, but users could purchase additional plug-in memory boards that were user-installable and could increase delay times to 1280ms.^[7]

Maximum Delay (msec)

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In 1983, MXR introduced one of the first multi-effect rack units for guitar and bass, the Omni.^[11] The Omni had 6 different effects: sustain, distortion, delay, equalization, flanger and chorus. The main unit was a 2U with separate controls for each effect. There was a footpedal (M-181) that enabled the player to switch the different effects on and off, as well as changing the order of the distortion and equalizer effects, a master bypass as well as an effects loop. Since 2006, the "M-181" product number has been re-appropriated by Jim Dunlop for the MXR Bass Blowtorch Overdrive pedal.

MXR Desktop Effects

In 1980 MXR released the MX-114 Two Channel Graphic Equalizer. From the 1980 Catalog: "The Equalizer's wide dynamic range and interface characteristics allow for a variety of applications. the frequency response of a system can be tailored to compensate for room acoustics, speaker aberrations and program material. Horizontal control placement and the equalizer's compact case permit easy manipulation in studio mix down situation. P.A. applications include: suppression of major feedback frequencies, compensation for high frequency attenuation in miking and rejection of unwanted signals (60Hz hum and noise) Two channels permit separate main and monitor equalization.^[12]

Drum Computers

In late 1981, MXR got the resale rights in the US to sell the KIT (M-178), a digital drum machine. In early 1983, MXR released the M-185 MXR Drum Computer, similar to Roger Linn's Linn LM-1 drum machine with individual pads for the instrument sounds and individual volume controls for each sound.