CAT original model, courtesy of

The Cat was a monophonic 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 the Odyssey, 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 moderately sought out on the collector market.  The SRM II seems to be the preferred model because of its digital keyboard and the circuitry is quite different from the older models.

The Original CAT[edit | edit source]

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 it's 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 duophonic keyboard but was unsuccessful because Octave presented prior art showing the duophonic design predated the ARP patent. 

The Cat had two VCOs (with suboscillators), a VCF, a VCA, two envelope generators, and an LFO.  The VCO utilized 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[edit | edit source]

Octave-Plateau Cat Ad 1980

In 1977 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, on the other hand, 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.  

An SRM I or 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[edit | edit source]


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 and to gain experience with technologies that Octave would later employ in the Voyetra 8.

Kitten synth

The Kitten[edit | edit source]

The Kitten was a cut-down 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.

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