E-mu PK-6 Proteus Keys

Back in 2001, this keyboard brought E-mu's legendary Proteus 2000 sound engine to a sleek, performance-ready package, packing 32MB of "Composer" sounds right out of the box—from lush orchestral swells to wild synth effects—and letting you expand up to 128MB with genre-specific ROM cards like Pure Phatt or Siedlaczek Orchestra.

At its heart is a sample-based digital engine with 64-voice polyphony, multimode resonant filters, dual LFOs, and a 24-bit dual stereo effects processor that handles everything from reverb to modulation with serious depth. The 61 semi-weighted keys respond to velocity and channel aftertouch, paired with 16 real-time controllers, a mod wheel, and 16 programmable arpeggiators with Super BEATS groove mode for instant live grooves—mute and enable on the fly with dedicated buttons. It offers four analog outs in two stereo pairs, stereo effects return input, full MIDI I/O/Thru, footswitch and pedal ports, plus 1152 presets (640 ROM, 512 RAM user). Measuring 40.75" wide by 13.3" deep and weighing 21 lbs, it's a sturdy, roadworthy slab with plenty of internal space for those expansions.

Players love its high-fidelity rompler sounds for ambient, IDM, and techno—vintage digital vibes like crisp pianos, jazzy Rhodes, and strings that fill out mixes nicely—plus the groovebox-like arpeggiation for quick ideas. Some note a few fluff patches amid the gems, and the interface takes a session to grok, but at today's used prices, it's a steal for Proteus magic in keyboard form.