CAT original model, courtesy of synthfind.com
The Cat was a duophonic analog synthesizer designed by Carmine Bonanno and manufactured by Octave Electronics from 1976 - 1981. This was Octave's first product and, at a price lower than most synthesizers at the time, it sold well. This article from Gforce's Web site says that there were a number of semi-official factory customizations and options available, which was not the case for the Cat's competitors. Three versions were produced: the original Cat, the Cat SRM I, and the Cat SRM II.
Cats are sought out on the collector market because of their classic analog sound. The Cat SRM II is the preferred model because of its digital keyboard, stable oscillators and the updated circuitry that is significantly different from the earlier models.
The Original CAT[]
Original Cat
The original Cat, released in late 1976, used a metal chassis design that was remotely similar to the ARP Odyssey but used a significantly improved synthesis architecture. Because of its low price and exceptional features, the Cat outsold the Odyssey. In an effort to slow sales of the CAT, ARP sued for patent infringement on the Cat's duophonic keyboard but was unsuccessful because Octave presented prior art showing the duophonic design predated the ARP patent. Several years later, ARP declared bankruptcy while Octave continued on to make the Voyetra Eight synthesizer as Octave-Plateau.
The original Cat had two VCOs with mixable waveforms and suboscillators, a VCF, a VCA, two envelope generators, and an LFO. The VCOs were a discrete design using a CA3046 transistor array and the VCF used cascaded CA3080 OTAs in a 4 pole design. The 3 octave keyboard was duophonic, so it could produce two control voltages, one of which would be routed to VCO 1 and the second to VCO 2. It had no pitch wheel, although there was a non-sprung slider on the panel that allowed pitch to be varied.
SRM I[]
Octave-Plateau Cat Ad 1980
In 1978 Octave upgraded the Cat to the "Series Revised Model "(aka SRM). This added several improvements, including an SSM2040 VCF, an LFO delay and a pedal input jack for offsetting the VCO1 frequency. The main improvement was the keyboard interface circuitry which included sample and hold circuits for both of the control voltages generated by the keyboard. On most duophonic synths of the era, there was only one sample and hold dedicated to the keyboard, so when playing duophonically, when the keys were released, the secondary control voltage would jump to the primary voltage, meaning that it was impossible to get duophonic notes in the envelope release phase. The Cat SRM would hold both control voltages, so a two-note chord would continue to sound as a chord through the release phase. This was an unusual feature for an analog duophonic keyboard and quite an improvement over competing designs.
An SRM or SRM II can be distinguished from the original Cat model by the pilot light next to the power switch, and a light next to the LFO FREQ control which flashes in synchronization with the LFO. In addition, the original Cat had white plastic stripping along the edge of the sides, while the SRM had walnut wood sides and the SRM II had veneer wood sides with wood pattern plastic stripping along the edges.
SRM II[]
Cat SRM II
The SRM II was released in 1980 in response to great demand from the UK synthesizer market. The discrete VCO circuits used in the earlier models were replaced by a Curtis 3340, the SSM2040 VCF was replaced with an SSM2044, the analog keyboard was replaced by a digital scanning keyboard which retained the duophonic memory capability, and most of the internal switching circuitry was replaced by CMOS logic ICs. These changes were primarily done to reduce manufacturing costs, improve reliability and gain experience with technologies that Octave would later employ in the Voyetra 8.
The SRM II also added extensive interface jacks on the back panel, allowing it to interface with modular analog synthesizers or to cascade multiple units.
Cat SRM II Features:
- Monophonic/duophonic keyboard plays two notes with memory function on second note.
- Digital keyboard with single contact per key (more reliable than the dual-contact analog keyboard used on previous Cat models and most other analog synthesizers of the day).
- Dual VCOs (CEM3340) with oscillator sync and mixable waveforms for complex tones.
- Sub octaves on both VCOs for full, deep bass sounds.
- Four-pole VCF (SSM2044) with adjustable keyboard tracking.
- Versatile modulation system to create a wide variety of sounds.
- LFO (with variable delay on sine output), S&H and dual envelope generators.
- White noise generator.
- Extensive expansion jacks on rear panel.
Kitten synth
The Kitten[]
The Kitten was a lower-cost version of the Cat, with one VCO and one envelope generator, but otherwise similar. The original model was introduced in 1977 and a Kitten II was released in 1980 along with the Cat SRM II.