Been thinking about this a lot myself... have a simple Sonic Frontiers, SFL-1 (Electro Harmonix tube) with a Cary "Rocket 88R" (Gold Lion and Raytheon tubes). Speakers in and out although right now a pair of very efficient Equation "7". It all plays incredibly. System synergy being the primary quality although the Equations are special. I have a chance to try out some interesting pieces. 1st, sub out the SFL-1 for a Luxman (Lab Series) 5C50 preamp. See how that plays and then pull the Cary for a Class A Sugden, Bijou Ampmaster. Going to play around a bit and see where, if any, the improvement lies. Nice to have access to such fine components