Roots Radical: Mu-Tron III


Define "boutique." Adjective: Pertaining to an item made by a comparatively smaller company that offers specialized wares to a specialized clientele. I think we can all agree on that definition, more or less. And while some folks can agree that Z. Vex started it, others would argue that James Demeter did with his Tremulator. Going by that definition, I would trace the roots of boutique back to Mike Beigel and Musitronics. 

Among the MXRs and Bosses of the world, Musitronics, or Mu-Tron, as it was colloquially known, blazed its own trails and played by its own rules. Its pedals were giant blocks of machined aluminum that were often bigger than one of the players’ feet, or sometimes even both of them.  

Many Mu-Tron pedals are named with Roman numerals, such as the Phasor II (and since it was the second one, the “Phasor” became known as the “Phasor I”), the Micro V, and the most important pedal in the line: the III, known more widely with the company name attached: the Mu-Tron III. 

The story goes like this: Mike Beigel and some of his MIT classmates developed a synthesizer of which Guild caught wind, and Guild was so impressed that it bought the Beigel synth. After the President who okayed the project died in a plane crash, the synth was shelved and Beigel decided to form his own company, selling the synth’s parts off in the accessory market. The III was born from this endeavor and was the first Mu-Tron pedal.

1974 Musitronics Advertisement

1974 Musitronics Advertisement

The results were spectacular. The III was the first envelope filter pedal on the market and everybody had to have one. Stevie Wonder bought one and mounted it to his clavinet. Jerry Garcia put one to work on Dead classic “Estimated Prophet” and others, the Police used one on “Too Much Information,” and many more acts used them; Red Hot Chili Peppers, the Meters, Zappa and Bootsy Collins all played a III, and the music world was better for it.

The entire Mu-Tron line was housed in enclosures designed by the same team that designed ‘50s Studebakers, and featured a hyper-futuristic look, one heavily inspired by ‘70s sci-fi movies. The III, as the flagship model, set this tone early, and because the III was the first of many envelope-controlled pedals, it made its own rules, offering what would become the standard feature set for envelope filters—switches for Mode (three ways), Range and Sweep, as well as controls for “Peak” and Gain. 

As it was the first envelope filter pedal, many companies released “their take” on the Mu-Tron, but it was never “right.” Companies like Ibanez and Multivox were the first to take cracks at the Mu-Tron recipe (with the AF201 and Spit Wah, respectively), but simply couldn’t recreate that Mu-magic, due to any number of factors. 

The fact is that the Mu-Tron units had a built-in transformer that accepted AC mains and spit out a bipolar power supply, along with a whole lot more real estate for beefier circuitry, leading well-known players to skip the copies and go straight for the classic, size be damned. Even today, as players struggle to fit armfuls of tiny pedals on one board, sometimes you’ll see a Mu-Tron III on there hogging half the blankets. And it’s 100 percent justified—the thing sounds that good.


Though Musitronics folded in 1980 (thanks, Gizmotron), many builders have since attempted to capture the magic. Lovetone released the Meatball, considered by some to be the finest envelope filter ever made, which was based on the III. Beigel ended up collaborating with Electro-Harmonix to release the entire Q Tron line, including the standard, Micro and “+” models, the latter of which is favored by John Mayer and has appeared on all his pedalboards going back several years.

A company known as HAZ Laboratories pounced on the trademarks after Musitronics folded, and has since produced a more-or-less bootleg version of the III, muddying the original’s legacy and further complicating the act of procuring a vintage model. 


However, Mike Beigel is at the helm of the Mu-FX company and has begun producing the III and several other effects, with the same quality that vintage worshippers have come to expect. His Micro-Tron III was released as late as last year and distills the power of the original III in a pedalboard-friendly enclosure. At last, Beigel is back and all is right in the Mu-niverse.

— Written by Nicholas Kula

Joseph Rubenstein