The LA2A and many other opto compressors use a plugin-in opto module referred to as a T4, which are readily available from a few manufacturers for around USD 100. As optos age, they become weaker, so after only a few years, the performance of an opto compressor may suffer until the opto module is replaced. Many companies besides Universal Audio produce optical compressors and each design may use a slightly different opto device, so their attack and release times may differ, or even be user-selectable. Their compression behavior remains natural and smooth regardless of a tube or solid-state engine, and the distortion and sonic color of a specific opto compressor relate to the amplifier circuitry, not the compression action. Optical compressors may contain tubes and transformers, or they may be solid-state and even transformerless. The LA-3A, an opto compressor with the tone of an 1176. The emphasis control was designed to provide radio stations with better control over the broadcast signal’s high-frequency content. This screw exists on the original hardware units (sometimes on the rear panel) and was factory set and perhaps adjusted by a studio tech to suit the studio’s preferences. Most digital models of the LA-2A and LA-3A provide an emphasis control (sometimes labeled pre-emphasis) that often looks like a slotted screw. Remember that the frequency-dependent nature of the opto blurs these parameters a bit-in a musically helpful way. The LA-2A provides two modes: compress (3:1) and limit (100:1). The fixed attack is fast, while the fixed release happens in two stages as described above, and would be generally characterized as slow. The user-adjustable parameters of an opto compressor are output gain and gain reduction (threshold).
The compressor then adds make-up gain with a tube amplifier (LA-2A) or a solid-state amplifier (LA-3A). In effect, the audio signal lights a small light panel and a nearby photoresistor senses the light and controls the behavior of the gain reduction. The magic of the LA-2A, and every other optical compressor that followed lies in an optical circuit that acts as the level control, or attenuator.
Universal Audio manufacturers an extremely popular hardware reissue of the original LA-2A to this day. By the mid-1960s the LA-1 developed into the current LA-2A compressor design- which has become a staple both as recording hardware and DAW-based software. Optical compressors date back to the 1950s when Telektronix (which eventually became part of Universal Audio) debuted the LA-1 compressor. The LA-2A hardware reissue from Universal Audio.
0 kommentar(er)
