I have been rolling tubes in and out recently, and each pairing was worse than the one before. Some pairings were too tubey, others not tubey at all, and none really added up to anything I wanted to live with. I was getting really discouraged and was about to give up until the last pairing was just WOW. That magical sound that there are no words to describe. The winning combination was a pair of RCA JRC 12AU7 from circa 1953 in the Candella, and a circa 1961 Dario MiniWatt in the EE DAC. Definately the biggest change I have experience that did not include a major purchase.