OPT4

Niviem OPT4 is a free opto leveling amplifier inspired by the legendary 1965 Teletronix LA-2A. Built around an authentic feedback compression topology, it faithfully recreates the smooth, program dependent response that made electro optical compressors the gold standard for vocals, bass, and mix bus processing. At its core is a detailed T4 opto cell model, complete with electroluminescent panel behavior, CdS photoresistor gamma curve, multi stage release, and memory effect. The audio path includes 12AX7 and 12BH7 tube stage emulation with selectable Dark/Bright tone character, UTC-style input and output transformer coloration, and selectable oversampling up to 32x for pristine harmonic generation. Beyond the original two-knob design, OPT4 adds creative control: Attack and Release character shaping, a sidechain high-pass (the famous R37 emphasis trimmer, extended to 1000 Hz), a sidechain low-pass filter, wet/dry mix for parallel compression, output trim, sidechain listen, and switchable MODERN/VINTAGE opto response. Natural COMP and LIMIT behaviors emerge directly from the circuit topology, not from fixed ratios. A/B comparison buttons let you toggle between two parameter snapshots without losing either. Nivipedia, the in-plugin encyclopedia, covers every control, mode, and concept at the depth the original 1965 design deserves - right-click any knob for "What is this?" to jump straight to its article. 38 factory presets across 9 categories. Cream chassis interface.