MU-TRON III original Patent Pending Musitronics Mu Tron III Envelope Filter effects pedal 117 Volts with power supply 220 volts 100% Working Condition

Musitronics, often shortened to Mu-tron, was a manufacturer of electronic musical effects active in the 1970s. Founded by Mike Beigel and Aaron Newman, the company's product line focused on filtering and processing effects derived from synthesizer components. The company was known for producing high-quality products with many user-adjustable parameters, but high production costs and a failed product line, the Gizmotron, caused its downfall.Their best-known product was the Mu-tron III envelope filter, "the world's first envelope-controlled filter", first made in 1972 and quickly becoming an essential effect for many funk musicians.

Phaser effects were common in the 1970s, but the Mu-tron Bi-Phase combined two phase shifting circuits and in its time was the preferred "the phaser-lover's 'phasor'". It used technology from the old Uni-Vibe, with lamps and photo cells, and featuring two independent sweep generators which could be coupled, each with individual rate controls and the option to choose square or sine waves. The unit could be connected to an optional rocking foot pedal so that the effect could be operated in the manner of a Wah-wah pedal. It was used by The Smashing Pumpkins as an integral part in achieving the "pumpkins sound" for the 1993 album Siamese Dream: "This is one of the secrets to our secret sound. This is the Mutron Biphase. We run everything through it - everything. It's fabulous", said producer Butch Vig in the video documentary Vieuphoria.

Beigel with the original mu-tron