Thanks Tsushima1. I read the various posts in the attached link. I suspect that ARC had either supplier issues and/or there were performance improvement gains by going with the new caps. My Ref 5 SE and Ref 150 both have the "old" white Teflon monsters.
I'm a big ARC fan and I believe that if ARC is using different coupling caps, it made the switch-out for good reason. I recall that I had to wait about a year before ARC called me to upgrade my Ref 5 to the SE version. One of the reasons for the delay: supplier problems. But as I said, it may be there are reliability or performance issues with the Teflon caps. Dunno.
Maybe if Hifigeek catches this thread, he will chime in.
I'm a big ARC fan and I believe that if ARC is using different coupling caps, it made the switch-out for good reason. I recall that I had to wait about a year before ARC called me to upgrade my Ref 5 to the SE version. One of the reasons for the delay: supplier problems. But as I said, it may be there are reliability or performance issues with the Teflon caps. Dunno.
Maybe if Hifigeek catches this thread, he will chime in.