I'm no expert, but every Siltech cable I have used, made a serious improvement on my system and ears. I own a Siltech HF9 SPDIF-75 ohms with WBT connectors (strange! the cable says it is 110 ohms) and a Siltech HF9 AES/EBU-110 ohms with average neutrik connectors. I prefer the HF9 AES/EBU. I use both to link either an old Electrocompaniet EMC-1 CD or a NAD S-500 to a fine Electrocompaniet ECD1 DAC (always I prefer AES/EBU). I have other good digital cables, which I find less musical than HF9 AES/EBU-110. They are:
a Mogami Gold AES/EBU-110 ohms, (infinitesimally harsher than the Siltech, but very good for its price and buid), and an ELCO UDC-S (spdif-75 ohms), good as the hf9-spdif.
