The UREI 1178 was essentially made up of two 1176s and built into a single stereo unit to overcome some of the issues usually associated with linking up multiple 1176 compressors.
1176 compressors are famously fiddly when it comes to stereo operation. An external stereo adapter (the 1176-SA) is needed if you want your 1176’s attack and release to track together. The pair of 1176s have to be connected and unconnected on the rear of the units with the dedicated 1176-SA RCA connections, which means that switching your units between mono and stereo is done behind your rack. The 1176-SA runs on 9v battery, and therefore causes your meter calibration to drift as the battery loses energy.
The 1178 aims to address these issues by essentially coupling two 1176 units inside the same unit. However, the 1178 had some shortcomings. The 1178 came out about the same time as the “Revision H” era of the 1176. This is the generation when the 1176 went back to a silver faceplate. Unfortunately this era did not see the Class A circuitry of its ancestors, and the input transformer had been replaced with a differential amplifier. These design changes apply to the 1178 as well.
Also, the 1178 has only one set of attack and release controls and only one ratio select. The unit has a STEREO / MONO switch, and therefore can operate in dual mono, but without independent controls for attack, release and ratio, you’re really only de-coupling the attack and release. The 1178 is really only practical as a stereo unit and therefore lends its self excellently to bus processing.
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