The Shadow Hills Dual Vandergraph is a direct descendant of the Shadow Hills Mastering Compressor and maintains its reputation of unquestionable quality and exceptional performance. It’s inner workings are developed from the discrete gain cells of the Mastering Compressor which are combined with the Optograph’s extremely flexible Sidechain Filter matrix. This combination provides great possibilities for new recording techniques and the dynamic control. This stereo compressor’s fully discrete audio path is Class-A and features Shadow Hills' custom Iron Transformers. The controls are: Ratio, Filter, Compression and Output Level. Just like the Mastering Compressor, the Compression and Output Level controls are Swiss made twenty-four position attenuators. The Ratio switch, selects between: 1.2: 1, 2.5: 1, 4: 1, 8: 1. In addition to changing ratios, each selection changes preset attack and recover times. The Sidechain Filter Matrix controls the frequency sensitivity of the side-chain. The positions are: 90 hertz, 150 hertz, 250 hertz and Bandpass. Input impedance 20k Minimum load impedance 600 ohms Stereo Fully Class-A Discrete audio path Discrete gain cells from Mastering Compressor Sidechain Filter Matrix from Optograph Swiss made discrete attenuators Military Spec build quality Meets the specifications of the VPR Alliance There is no limit to the number of Dual Vandergraphs that can fit into any 500 series rack