Looking over your list, all nice quality built stuff. Guessing it seems more like an itch to change than your Bryston amps wearing out, eh?. If it's all truly "less than 5yrs old", gotta quick question for ya. How long do you leave it all powered on for...days, weeks, never turn it off? Noticing your Ref 6SE line state preamp has a number of tubes in it, right? If you have not checked this already, can you pull all the tubes and go have them tested somewhere locally. Make sure they are okay first, or replace as needed. If tubes check out okay, maybe find local tech to go in and check all specs, caps, in your amps next, after. Ref below:
Tip from a recent article, quote:
"To get the most from the REF 6 tube complement, one menu option allows the user to see the number of hours on the current tubes. According to AR, new 6550WE tubes should serve their owner for about 2,000 hours, and the 6H30 tubes offer roughly twice that life span. When the tubes eventually wear out, ARC offers carefully matched replacement tubes. As there are not a lot of variations on the 6H30 tube, just giving the factory a call is the easiest way to roll.", unquote.