Before I purchased my Analoguetube units, I diligently researched literally every modern day, high end, Vari-Mu Compressor that staked it's claims to be a Fairchild clone, or just sounded like a Fairchild. As best as possible, I compared tubes, transformers, electronic components, and how the units operated. Although Vari-Mu Compressors add a unique flavor to a track or mix bus, Simon's units, based on the exact, original, Fairchild designs, are superior to any other models