Interesting discussion all
The HS-Link is an
LVDS system that connects only Accuphase products. The transmission consists of two signal pairs, one is the raw data, and the other is the key signal to 'encrypt' source to load to make sure, there's no illegal SACD data going anywhere other than Accuphase components.
The HS-Link connection conforms to the
T-568A connection of the RJ45
The data pair is located on Pins 1 & 2 (White/Green & Green)
+Ve and -Ve respectively
The Key pair is located on Pins 7 & 8 (White/Brown & Brown)
+Ve and -Ve respectively
Pins 3, 6 (White/Orange & Orange) are connected together with the metal shield of the RJ45 connector S1 and S2 and all four are connected to the frame of the device also equal to 0V internally.
Pins 4, 5 (Blue & Blue/White) are not used.
Very wisely Accuphase have separated the signal as far apart as they can be, and with the 0V in the middle, works.
Electrically, you can then use
any straight Ethernet cable and the HS-Link will work. Since Accuphase have gone to the trouble to keep noise to a minimum across the interface, the use of a shielded cable 'would' be necessary.
Since most installations have the source and load close by, the standard length of 1.5m cable as Accuphase delivers will work. Unfortunately in my installation, the DP-720 and DC-950 are separated by 4m of HS-Link cable. I use a standard Lindy shielded 5m Ethernet cable, it was to hand, so I used it. Still there after nearly 2 years, sounds great (to me). I have not upgraded the cable since 'good' Ethernet cables are expensive for 5m lengths.
Interconnecting cables will always make a difference, so whatever sounds best, and in this case, no exception.
As far as HS-Link is concerned, the Ethernet cable should be shielded (at both ends) and with the minimum amount of cable length and maintain the same connection point of the AC supply for source and load. This is mainly to ensure the earth (safety ground) potentials are as close as they can be to avoid ground loops.