Moog Taurus
A pedal synthesizer that gave a keyboard player's feet a bass section. The service manual shows how seriously Moog took it.
Overview
The Moog Taurus is a bass pedal synthesizer. It sits on the floor, you play it with both feet, and its job is to put a low end under a band that otherwise wouldn't have one. The surviving documentation for the model is the Model 343A service manual, copyrighted 1982 by Moog Music Inc. of Buffalo, New York. It's an unglamorous document: trim-pot adjustment procedures, a mechanical replacement parts list, warnings about not stripping screw heads. Underneath all that is a seriously good analog voice.
The synthesizer section is built around two oscillators. Oscillator 1 offers sawtooth and a 50% duty cycle square wave. Oscillator 2 offers sawtooth and an 85% duty cycle pulse. Both switch across 32', 16', and 8' octave settings. Oscillator 2 can be synced to Oscillator 1, either hard sync or a "contoured sync" mode in which the contour generator sweeps Osc 2 through a range of up to four octaves. The interval control between the two oscillators spans 18 semitones. A separate noise source goes through the filter and VCA like any other signal.
The filter is the heart of it: a patented 24 dB/octave low-pass design, the Moog ladder in pedal form. It has keyboard tracking on the cutoff and a regeneration control that pushes the filter toward self-oscillation. The contour generator runs from 5 milliseconds to 2.3 seconds, with attack time bottoming out at 4 milliseconds and decay reaching 6 seconds. Glide is continuously variable, and the pitch wheel range is ±7 semitones. That suits the slow portamento bass lines the Taurus was born to play. The VCA offers both a keyed mode and an auto-trigger mode. The rear panel carries audio in and out, keyboard out, trigger in and out, and a V-trigger input that responds to a +3 to +10 volt gate.
The unit is compact for what it does. The synthesizer chassis measures 21 inches wide by 6-3/4 inches deep by 4-3/8 inches high and weighs 7 pounds, with the pedal assembly carried separately. Moog's manual says all internal adjustments are reachable through the rear panel holes with a 1/8-inch screwdriver, so routine calibration needs no disassembly. The bottom cover comes off with eight No. 6 self-tapping screws, which exposes the pedal suspension and switch actuator tabs.
The power supply is a non-standard arrangement: 24 volts AC nominal, 28 volts AC maximum, at 50-60 Hz, drawing 6 watts. That's not a wall-wart-friendly voltage, and it's the first thing to check when evaluating a used unit.
Used Taurus pedals rarely surface. Sound on Sound (June 1995, p.184) observed that the main reason for the scarcity was simply that owners didn't want to part with them, and called it a seller's market. The same piece (p.185) recommended leaving the pedals switched on for a while when inspecting a used unit, specifically to test tuning stability.
A later Moog product, the Taurus II, was described in Mix (February 1982, p.65) as a low-cost 1½-octave pedal synthesizer with detachable electronics, full modulation, and performance controls. It is a different instrument from the original Taurus.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.