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Universal Audio Teletronix LA-2A Leveling Amplifier |
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The Universal Audio Teletronix LA-2A is a single channel tube based compressor (leveling amplifier). It was originally made back in the 60's for broadcast purposes but became on of the better sounding leveling amplifiers (compressor). It's simple design and natural sound was what made it so popular. The main difference at the time was its main circuit design that uses an electro-luminescent optical circuit for gain reduction. This circuit doesn't add distortion when it modulates the sound as many other designs do. Electro-Luminescent systems respond faster than that of electro-optical circuits and this response speed is another reason for its popularity. Every time you apply EQ, Compression, or even delay to an audio signal, is it digital or otherwise, basically applies a controlled amount of distortion to the sound. When using a compressor for example you are limiting or reducing the dynamic range the sound signal. This usually ends up adding odd harmonics that inject a form of undesirable distortion to the sound. The LA-2A uses a "unique electro-optical attenuator system allows instantaneous gain reduction with no increase in harmonic distortion". This means that it can compress the signal while still sounding natural. The LA-2A is a transparent compressor, meaning you don't hear the compression but you get a more consistent gain from the signal. The release characteristic of the unit is achieved using a 2-stage photo-electric cell. Universal Audio manufactures these units to the specifications of the original by hand. You may want to go to the UA site and look at the pictures of the unit. If you look at the back pictures you'll see that the tubes are not enclosed in the 19" rack mount case. They are out in the open so when finding an appropriate place for it in your rack you'll need to know this. Its needs room to breathe as well as enough ventilation room. Also keep your cords tied up or you may find it melting on one of the tubes. This unit like the Manley massive EQ can get really hot. The inputs are located on the back panel of the unit. There are two types of connectors: 1) XLR 2) Barrier Strip. If using the Barrier strip it's best to keep the length of the cables less than 2 feet. It includes STEREO LINK connections on the barrier strip. This allows you to use two LA2A together (Stereo) for stereo mastering for instance. You can also use it in Side-Chain operation (Ducking). It provides a potentiometer on the back panel that allows you to change the frequency range where the LA-2A is most sensitive to. The controls are very simple, two knobs: Peak Reduction Control, and a Gain Control. The Peak Reduction Control sets the amount of compression (dynamic range) while the Gain Control is used to usually increase the gain of the compressed signal. When compressing the gain of the sound is reduced (lowering the louder parts) so the Gain is used to get it back to nominal. There is another switch (the black knob upper right) which is used to set the VU Meter response. It selects what information the VU meter will show. It can monitor the output level, or gain reduction level. Another toggle switch located on the lower left side is the COMPRESS/LIMIT switch. This basically selects the way the compressor will respond. The LIMIT selection is used for Limiting and has a steeper slope. From my experience using it you get a somewhat fatter signal without the harmonic coloration, other than the coloration brought about by its increased volume/gain. It sounds great for vocals and voice as well as the stereo master output. It has a sound of its own. Features
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