This is a nice thread with some interesting and thoughtful answers. Some people put some serious time and thought into their posts. I just want to talk about my journey from all SS in the 90's to today. I actually had well modded Citation V (tube)power amp at one point. Later I had a tube pre and a warm CJ SS power amp. I swore this was the ultimate combo tonally, although I wanted a tube power amp, as a power hog I could not afford a high power tube amp. Today I have a passive line stage connected to my tubed Trivista CDP and tube phono stage. I connected my CDP direct to my amp when working on my preamp and learned the output from it was too much! What this meant was my tube preamp was really an attenuator! Since my tube preamp had tons of gain it also introduced a noise floor. This is why I go passive today. Another reason is the MF Trivistas(tubed CDP) huge low impedence output. Not all source components are suitable for passive. Neither are all power amps. Sensative high impedence power amps are best. My two CJ's are 100K ohm input impedence and senstative. Removing the unneeded active linestage was like removing the scrim in front of a movie screen. I also did a lot of cable and power improvements which all make a wonderful difference. Good cables as both power and interconnects really improved the top end and made it smoother and much more detailed. So my answer is I use tubes on my sources and in my current biamp setup I would use tubes on the HF side if I could afford something nice. Don't underestimate cabling for improving sound as well.My system is much less edgy sounding today because of these upgrades.
ET
