The DK600 is Siel's unique Italian take on the mid-eighties programmable polysynth with MIDI implementation (badged as the Opera-6 in the UK). Just like the Juno-106 and Poly-61 of the time, the Siel was a 6 voice synthesizer with straight forward programming, simple effects and digitally controlled analog oscillators (DCO's). However, the Siel, having dual oscillators per voice sounds thicker than the Juno or Matrix because it's got 12 oscillators! And because they're DCO's, you know they'll always remain stable and in-tune even though they are analog in nature.
The DK600 has many other nice features such as complete MIDI implementation. There are 3 LFO's for extreme modulation. Both the filter and amplifier have standard ADSR envelope sections. And like similar synths, all the sliders and buttons are intuitively placed on the front panel for hands-on real-time programming.
The EX600 Expander module was also released (pictured above), featuring the same great internal synth engine as the DK600. However, the Expander is not programmable except from a DK600, an external MIDI sequencer or editor such as Unisyn. The Expander was intended to be programmed by transferring patches from the keyboard version. It's not rack-mountable either so it's usually best to go for the keyboard version. After all, the keyboard features the great layout of controls, velocity sensitivity and 61 notes (5 octaves)!