Time to retube the 66. I've had the Route 66 for years and never retubed. At Brent Ferguson's advice, I got Genalex Gold Lion KT66s instead of the Groove Tube units that have been in there since day one. Also tested brand new Winged C EF86, a JJ Gold Pin 12AX7 and a new Russian Tung-Sol 12AX7. It's nighttime and I can't do a full-bore test, so this is about listening at a low, clear level. Maybe I can repeat it sometime soon "at volume"... To really tell what I was hearing, I recorded a few chords, some single lines and some Tone-Bender fuzztone into a looper. Then I played it back through the stock tubes and recorded into an Edirol R09 handheld recorder. Then I made these changes, playing the same loop for the recorder each time: 1. Change out the KT66s 2. Swap in the Tung-Sol 12AX7 3. Swap in the JJ Gold Pin 12AX7 4. Swap the EF86 for the new one 5. Put the original Sovtek 12AX7LPS back in. I loaded all the sound files into Audacity and lined them all up time-wise. I soloed the 6 tracks all over the place during the playback about 50 times. I have to tell you, the improvement and difference was all the KT66s. The GL's sound deeper, clearer, bigger. I could only hear the tiniest bare sliver of a difference between any of the other tubes. I mean it was next to nothing. So I put the original Sovtek 12AX7 back in! Maybe I have a freak miracle Sovtek because I usually don't like them very much. I expected a night and day difference, figured none of the tubes had any tread left on them... Later on, we'll see how things change when we're cranked a bit, but this was a surprising outcome. I expected some major differences even at this level.