The Shadow Hills Mastering Compressor has extraordinary functionality, and also provides mastering grade compression and limiting for tracking and mixing. Essentially it is two compressors in series, per channel, that can act in stereo, or dual mono. First comes our mastering grade electro optical compressor, followed by our discrete Class-A compressor/limiter. Both feed our switchable custom output transformers, Nickel, Iron, and Steel. There is enough gain in each section to overdrive the hottest tape, or clip your converters, if you're into that sort of thing. The input stage is transformer balanced, followed by our fully discrete optical compressor. This section utilizes the same T4B optical attenuator as the LA2A and LA3A, but is optimized for mastering. The second stage is our discrete Class-A VCA compressor. There are no electrolytic caps or IC chips in the audio path. There are six ratios: 1.2 to 1, 2 to 1, 3 to 1, 4 to 1, 6 to 1, and 10 to 1. There is six attack settings: .1, .5, 1, 5, 10, and 30 milliseconds. And there are six release times selectable: .1, .25, .5,8, 1.2, and Auto. There is an insertable filter in the side chain to limit pumping with bass heavy material. Lastly the signal goes through our new Shadow Hills custom transformer-switching network. The first position is Nickel, which is our custom version of a famous L. A. custom console. Next is Iron. In this mode the signal goes through our op-amp and into a Class-A output stage then to our custom Iron transformers, the last transformer position is Steel. These selections allow you to choose between different output transformers that are in effect: clean, colored, and dirty, respectively. The optical section has a hard-wired bypass that completely removes it from the signal path, and the Class-A VCA compressor is also hardwire bypassable, completely removing it from the chain. It is possible to independently bypass both compression sections and have your signal go through the input transformer and transformer selector only. There is also a hardwire bypass for the entire compressor, effectively a strait wire in and out of the box. So besides being a mastering grade, and highly functional buss compressor, it serves as an excellent tracking compressor. For instance, you might call up the chain of the optical compressor, then to the Class-A output and Iron transformer, for vocals, or select just the Class-A VCA compressor with a 10:1 plus the Steel transformer for crushing some room mics, and on and on. The metering can reflect, optical gain reduction, discrete gain reduction, or output level. The Magic eye tube follows the output meter to act as a peak meter. All 17 of the rotary switches are detented. The front panel is engraved. The knobs are bake-lite.