E-mu E4 (1994–2002)

The E4 was E-mu's fourth-generation Emulator. It arrived in 1994 as the company's direct challenge to the Akai S3000 series. At launch, the E4K keyboard version went for $9,430 in the US (£6,270 in the UK). The rackmount E4 was £5,750 and the pared-down E4X was £4,630.

Inside, the E4 pairs two custom silicon-gate DSPs with a Motorola 68k processor. It runs E-mu's E-OS operating system, which is upgradeable via floppy. It shipped with 16 MB of RAM, expandable to 128 MB, and gave 64-note polyphony on the E4 and E4K. Audio conversion was 18-bit at 44.1 kHz, with a 100 dB signal-to-noise ratio and THD+noise of 0.002%. SPDIF and AES/EBU digital I/O came standard. So did four inputs, configurable as two stereo or four mono pairs. A built-in effects processor handled eight simultaneous effects, and optional expansion boards could bring the analog outputs up to eight individual channels. The internal 270 MB hard drive could be replaced with any standard 1.3 GB SCSI drive, and both internal and external SCSI ports were fitted. The E4 worked as a 16-part multitimbral instrument, with full sample editing including truncation, looping, and time-stretching.

The E4X is where the record gets murky. Vintage Synth Explorer lists it as a 1U rack unit with 32 voices. Sound On Sound confirms the 64-voice count only for the E4/E4K. So the E4X may have been a reduced-voice version, though no single source states this explicitly. The keyboard E4K had balanced XLR outputs.

Collector interest in the E4 has been rising among electronic music producers chasing the classic E-mu sound. Used units typically sell between $500 and $1,200. The rarer E4K keyboard commands more, and one recently went for $1,500 on Reverb. There are two well-known failure points. The original LCD displays frequently fail and are hard to read, and drop-in replacements run $100-$150 and may require soldering. The floppy drive is a common failure after 20+ years, though a USB floppy emulator works as a replacement. The internal CR2032 battery should be replaced proactively, because if it leaks it can destroy the board. The E4 will also not boot if more than 128 MB of RAM is installed, so oversized SIMMs cause boot issues. Standard 72-pin SDRAM works fine, and any standard SCSI drive will do for storage.