*Please note this item is pre-owned and may show signs of use. Please see photos.

The K1000 also came in a series of rackmount synths. The so-called "1000 Series" consists of no less than ten different models of the rackmount version of the synth. Each module in the series has a different set of sounds. Complicating things further, you could upgrade these modules, so that they may have one name on the front panel, but have the features and sounds of a different model from the series. Some of the upgrades include:

• 1000 AX Plus Acoustic Expander (185 presets - all SX and HX plus more)
• 1000 GX Guitar Expander (100 presets)
• 1000 HX Horn Expander (75 presets)
• 1000 HXA Expansion ROM: Soprano sax, Alto sax, Baritone Sax, Brass stabs
• 1000 SX String Expander (99 presets)
• 1000 SXA Expansion ROM: Clarinet, Flute, Oboe , Bassoon, Fr. Horn, Timpani
• 1000 PX Professional Expander (120 presets)
• 1000 PXA Expansion ROM: Flute, Rhodes, E. bass, Drums, more waveforms
• 1000 PXB Expansion ROM: Steel guitar, Harp, Marimba, Tenor Sax, Percussion

Kurzweil later added aftertouch to the K1000 (an upgrade not available to owners of the original K1000), known as the K1000SE (Special Edition).