The Opus 21 was reviewed in the July 2003 issue of Hi-Fi Plus. As I remember it, the reviewer was using the Nordost DIN to RCA interconnect and found quite an improvement over the RCA output. Here is the link:
http://www.hifiplus.com/
I used the DIN to RCA interconnect with bullet plugs made by DNM. You can get a pair from Jeff Kalt of Resolution Audio for $150. I haven't tried the other more expensive ones but the DNM works well for me and leave me satisfied. At least I am not going back to my more expensive RCA interconnects.
Hope it helps.
http://www.hifiplus.com/
I used the DIN to RCA interconnect with bullet plugs made by DNM. You can get a pair from Jeff Kalt of Resolution Audio for $150. I haven't tried the other more expensive ones but the DNM works well for me and leave me satisfied. At least I am not going back to my more expensive RCA interconnects.
Hope it helps.