Set it and forget it! The Manley Langevin ELOPTM Limiter makes things easy. The principle of operation is based around using a rectified sample of the audio to shine an LED (Light Emitting Diode) onto an LDR (Light Dependent Resistor). The photo-resistor in combination with a fixed resistor simply act as a changing voltage divider to attenuate the signal, a kind of intuitive volume control. A similar principle was used in old Teletronix® & Urei LA-2A®, LA-3, and LA-4 units which used a slower electro-luminescent panel-light on a conventional LDR encased in a light-tight enclosure. The Manley Langevin ELOP uses modern VACTROL technology (with a twist) for exact sample-to-sample tracking and no high frequency loss whilst limiting heavily, a problem commonly associated with older LA-series limiters and other opto-based units.

Audio signal passes only through all-discrete Class A amplifiers in this Langevin ELOP. Each channel can be run separately or switched to stereo link. Due to their inherently quick attack, these Electro-Optical Limiters are excellent for tracking vocals or individual instruments.