Musitronics gear on the Anagram

Musitronics was a small New Jersey company whose Mu-Tron III, designed by Mike Beigel and released in 1972, was the company's first product and one of the earliest envelope filters on sale. It reads how hard you play and sweeps a filter open to match, giving the quacking, vocal tone that funk bass and clavinet parts are built on. The company did not last long, but the effect became a staple.

None of the three Anagram blocks in this family names the Mu-Tron III outright, so none is confirmed.

Nembrini Audio describes Envelope Filter as a classic 1970s optical auto-wah. That points strongly at the Mu-Tron III, which used a light and a photocell to follow your playing, so the badge reads likely. Dirty Boys Audio's free SmulTron III Envelope Filter plays on the name but describes a hybrid circuit of its own, so the link is our guess. Cognate Audio's Cognate Kinetic describes OTA envelope filters in the classic tradition, plus a Minimoog-style ladder filter mode; the Mu-Tron lineage is our guess.

Envelope filters reward a steady right hand. Too much sensitivity and every note opens fully, so the effect stops moving. Too little and nothing happens. The Mu-Tron sound sits between, with a fast, round sweep that follows your dynamics.

On bass, low resonance can get boomy at high settings. SmulTron III has a control to tame the sub, and Kinetic sets its own sensitivity so the sweep stays consistent from one room to the next.

Try SmulTron III first. It is free, and it is a quick way to learn what sensitivity and resonance do before you spend money on the others.