via this listing
"This is a large semi-modular synthesizer, designed in Australia and released as a kit by Electronics Today International magazine in 1973. The large aluminium panel pivots forward for maintenance. Its 22x22 matrix switchboard, joystick, complex modulation and feature set is reminsicent of a larger EMS VCS3, a comparison enhanced by the use of genuine Cliff "little Dalek" knobs.
The main modules in the 4600 design were repackaged for the (smaller) ETI 3600 and the lightly larger Maplin 5600 kit synthesizers. Its notable features are volts-per-herz VCOS (rather than volts-per-Octave linear VCOs), complex Transient Generators that are like simple three stage sequencers, and a different-sounding VCF.
This is a rare, powerful and unique synthesizer that needs some TLC from a competent builder to unlock its potential.
STORY
In the early 80s before it had been completely built, it suffered damage (the plaster ceiling collapsed on it, because of a shoddy repair job after the previous tenants, a punk gang, had a "demolition party" that destroyed all internal walls). The keyboard was destroyed and there seemed little reason to replace it (the first 4600 keyboard circuitry was problematic and had been replaced by a design from the Fairlight team.) There was some scratches to the case and a lot of dust, though the pots did not seem scratchy.
