Thanks for the reviews. I recieved a pair of 5" silver ICs in early June and after the Darwin-prescribed several hours of breakin was not a happy camper. Tonally they were among the best I'd heard, although on the dark side, but otherwise I found them lacking in what I call blossom or bloom - emotionally constipated (constrained), instruments and voices hardly more than two dimensional, and instruments back from the mike quite soft. Over the course of 300 hours on my desktop system (Cuinas Dac, Emotiva airmotiv 4 w/ HiFi Tuning fuses), and then another equal amount with my TV system, they gradually opened up but still weren't satisfying. Probably headed for the used market.
Then recently (and very belatedly) I heard about the Isotek System Enhancer and Rejuvenation CD and decided put the Darwins through about 20 hours with its large system file. What came out the other end was a different cable. Wider and taller soundstage, greater clarity and sense of depth, dynamics improved and speedier, tighter bass, instruments and voices now have more air and body, and tonal darkness gone. The main thing that seems a touch limited (compared to the Grover Huffman IC) is top end shimmer and air. But then I suppose the good side of that is bright recordings are more palatable.
Then recently (and very belatedly) I heard about the Isotek System Enhancer and Rejuvenation CD and decided put the Darwins through about 20 hours with its large system file. What came out the other end was a different cable. Wider and taller soundstage, greater clarity and sense of depth, dynamics improved and speedier, tighter bass, instruments and voices now have more air and body, and tonal darkness gone. The main thing that seems a touch limited (compared to the Grover Huffman IC) is top end shimmer and air. But then I suppose the good side of that is bright recordings are more palatable.