UP FOR SALE IS THE HIGHLY DESIRABLE COMPEX LIMITER! I'M SELLING BECAUSE I NEED $$ AND DO NOT HAVE TIME TO REPAIR THIS VERY VERSATILE COMPRESSOR/LIMITER. THIS IS THE VINTAGE MODEL AND IS IN VERY GOOD COSMETIC CONDITION. ONLY BEEN IN A SMOKE FREE STUDIO. USES:
EXCELLENT ON DRUMS! (SIDECHAIN PROCESSING AS WELL)
GREAT GUITAR CRUNCH
MANY OTHER SOURCES
NOTE: A REPAIR WILL NEED TO BE DONE TO THE FIRST CHANNEL AND I SUSPECT IT HAS TO DO WITH THE GAIN STAGE (DISTORTION AND LOW INPUT). FOR THIS REASON, I'M DEEPLY DISCOUNTING THIS VALUABLE PIECE OF 60'S HISTORY.READ MORE BELOW:Throughout the 1960s, '70s and '80s British manufacturers Audio & Design (Recording), now called Audio & Design Reading, enjoyed a phenomenal reputation for class-leading audio signal processors. Their now-classic F760X RS 'Compex' dates from the very late '60s. It was an elaborate and incredibly versatile compressor-limiter-expander, which employed discrete transistor electronics, with a single FET gain-reduction device in a form that ADR called a 'vari-loss amplifier'. FET-based compressors were popular back then, but what made the F760X unique was the way in which this FET was driven simultaneously by the combined control signals from three separate side-chains (limiter, compressor and expander).F760X-RS 'Compex' LimiterThe F760X 'Compex' limiter was made up of three main parts; a compressor, and a 'noise reducing' expander/gate. All of these parts could be used separately or together for well controlled sound limiting. This combination came about from client feedback. From the feedback ADR designed and built the first units, these were labelled as F760X-RS (RS meaning ). Later modifications were made and another version was released with a better, ergonomically designed, front panel. This later model was labelled as the 'Compex'. The 'Compex' limiter provided peak limiting with a multi-ratio, variable threshold compressor. Ratio settings ranged from 1:1 to 20:1 and there were controls for threshold and release time. The inclusion of an expander/gate provided attenuation of the gain during pauses in the audio signal to reduce noise caused by compression; the expander/gate could also be used for special 'punchy' effects, favoured on drum and percussive sounds. Noise gates were often criticised at the time for 'hunting' around the threshold point. The 'Compex' used clever around the gate, this was important to stop unpredictable opening and closing of the gate; the open threshold was higher than the close threshold. The gain reduction controlled by the 'Compex' was monitored from two meters located to the right of the front panel. There were two light indicators; a red light lit when the signal level reached its peak, and when in expand mode a green light was lit. There were a set of lights for each channel, depending if the unit was the stereo or mono version. There were some different models of the 'Compex' available; one of these included a smaller console module named the F760-N. This version was built without the expander/gate, it later had an expander/gate added and was then known as the F760X-N. There is also a rare version called F760X-RS/T. One of the visible differences are the VU-meters, which got the brand "Audio & Design Recording LTD." and if you look on the rear, there you can see the type. The "T" stands for transformer, which are said to add harmonics to the sound.The "T" version was mainly used in broadcasting stations, mainly because of its SNR and headroom. ADR also built an F760 version for the Helios mixing consoles.
https://en.wikipedia.org/wiki/Audio_%26_Design_(Recording)_Ltd