I have been using ARC pre with Pass Labs amps since 2002. I love the combo. I started with the X-350 and am currently using the X260.8 mono’s with the Ref 5SE/Ref 2SE phono. This combo was great with my Thiel speakers for many years as well as with my current Wilson speakers. Together they make music fun. I put about 1300 hours/year on my system per the tube counter in the Ref5 SE.
One thing about tube vs SS amps- damping factor. Tube amps have low damping factors compared to Pass Labs SS amps. Matching tube amps to speakers and speaker cables is much more critical work compared to SS amps.
I enjoyed my ARC CD player for many years. I have heard the CD9 in an all ARC system a few times- very nice. One day I heard someone’s system in their home who was using an Ayon CD (SACD) player. I was very impressed. So a couple of years ago I bought the Ayon Stealth XS and CD transport. I was blown away by the sound. I also found a good power cord increases the pleasure even more. The Stealth XS uses 6n6P tubes vs. the Stealth which has the familiar 6H30 tubes in the output. They also use 6Z4 tubes in the rectifier. Avon’s top CD player uses 6H30 tubes in the output section. I opted to go the separate DAC route although it is a bit more money. The Stealth DAC is also a preamp but I like the sound better going through the Ref 5SE. The Ref 5SE expands the soundstage width and depth.