ATCX

Back in the early 2000s, this rackmount synth shook up the analog scene by packing four legendary filter personalities into one box, letting you flip between Moog ladders, Oberheim SEM warmth, Roland TB-303 bite, and ARP 2600 edge with a single switch—no cartridges needed like its predecessor.

Its two analog oscillators deliver triangle, sawtooth, reverse saw, square, and pulse waves that can run simultaneously, feeding into a voltage-controlled filter array with 24dB/12dB low-pass and bandpass modes, all backed by three multi-stage envelopes for precise ADSR shaping on filter, amp, and mod duties. Two LFOs offer triangle, saw, square, noise, random, and sample-and-hold waveforms assignable to pitch, pulse width, filter freq, resonance, and more, plus crossmod, white noise, exponential glide, analog distortion, and a patchable ring modulator for external processing via dedicated ins and outs. Controls center on a single smooth optical encoder with membrane switches and a 3-character display for editing, housed in a compact 2U blue rack unit with MIDI in/out, audio out, and ext input routed to the filter and VCA. Full MIDI implementation handles program changes, CCs for dynamics/modwheel/pressure/bender, sysex, and 512 internal RAM patches for instant recall.

Players loved its fat, versatile monosynth tones for bass, leads, and experimental electronica, praising the chameleon filters and powerful signal path, though some noted the menu-diving encoder takes getting used to for live tweaks.