This review of the Moog Opus 3 was done by Mike Moran in International Musician (and Recording World) from May 1981.
The Moog Opus 3 is a little bit late on the scene being a similar price and having similar functions to other instruments by Roland, Yamaha and Korg. The keyboard is a C to C 49-note polyphonic and is basically a string (organ) brass combination, although the envelope and the filters do allow a number of different sounds based on those three originals.
The front panel is a mixture of knobs and sliders, but I found it difficult to work with at first particualrly when (as can happen) one control _has more than one function – (e.g. th_e chorus/string level). The string footages are 8′ 4′ or both and the string waveform is sawtooth. Sliders vary the frequency anti resonance of the filter, and equalisation can be chosen from low, high, or Band pass.
I have always found the polyphonic Moogs to have a predominantly organbased sound salvaged only by efficient filters, so its somewhat surprising to find the organ part of the Opus 3 to be the weakest part.
The fixed waveform is square wave, and the footages are 16′ 8′ 4′ 2′ 1′ (all with separate level controlls). There are unfortunateiy no harmonic footages which are an absolute must for anyone wishing to use a convincing solo organ sound. The organ section however is useful when employed together with the other sections to add weight (16′ with strings) or effect (higher footages with the brass).
The brass waveform is sawtooth and the footages are 16′ 8′ or 4′. The brass section has its own release, decay and attack and also has sliders for contour emphasis and frequency; so you can either set up your own brass sound or use the preset. I was pleased to see the Opus 3 has a stereo output mixer with a master gain, separate pan, level and on/off controls and colour coding for each section . The rear panel has left and right stereo outputs, a mono output and a sustain footswitch input.
Dimensions are 5%” high x 145/ 16″ deep x 29.” wide (or 14.3″ cm x 37.9 cm x 75.6 cm).
Net weight is 20’Ib (9kg) and price is £699 including VAT. Sutnmary Competitively prices but less versatile than similar products from other manufacturers. It has the advantage though of a reasonably distinctive sound, and I did like the brass section. Keeping costs down and giving customers a number of features does of necessity mean compromise, but most frustrating was the fact that there is no choke between single or multiple triggering. Still, a useful machine for Moog fanciers and others who will like the sound quality rather than a fascia full of gimmicks.