This is an expander unit for an Akai S1100 sampler rack mount unit. The Akai S1100EX is not a sampler on its own. It answers the one complaint S1100 owners couldn't shake: not enough voices. It was designed only to expand the Akai S1100, and it adds 16 simultaneous voices and 8 individual audio outputs. In Voice Expansion mode that effectively doubles the polyphony. It has no front-panel controls and no sampling inputs. It uses the host S1100's interface, with MIDI for note data and SCSI for sample and edit transfers. It is a purpose-built extension for rigs where track counts were pushing limits and multitimbral arrangements needed more headroom.

Owners report two ways to use it. In Mode 1, the S1100EX acts as a fully independent S1100. It shares storage via floppy or hard disk and borrows the host's display for navigation. That turns one sampler into two separate instruments, so you can layer complex arrangements without voice stealing. Mode 2 is Voice Expansion mode, where the S1100EX and host combine to deliver 32 voices total, or 16 voices in full stereo. According to documentation, when loading samples in this mode, the S1100EX loads first, then the host follows, so playback stays synchronized. The unit has an internal FX card identical to the one in the S1100, so you keep effects processing in expansion.

It connects via MIDI and SCSI, and up to six S1100EX units can be chained on a single SCSI bus. In theory that allows massive voice counts, though such setups were rare in practice. The rear panel has a pair of audio inputs, not for sampling but for cascading audio. Route the stereo outputs of the S1100 into the S1100EX and the sound passes through both units, which is useful for processing or output routing. A headphone socket is also on the back, which some find awkward and others accept as a trade-off for rack efficiency. The host S1100 must be updated to version 2.00 firmware, which involved both software and hardware changes, including new EPROMs. Some benefits were available through software alone, but full functionality required the full upgrade.

I owned an S1100 a few years back, and this has been sitting around since then. It has 4 mG RAM and the 64 voice card installed. I have no way of testing this any longer, and am selling as is, no returns. The 64 voice expander card and memory cards are worth the asking price alone!