[80B]

Tom,
"Here’s the catch - by the time I pull the amps out, get the covers off, swap the tubes, power up for 20 minutes, listen, cool down, swap tubes, power up for 20 minutes, listen, cool down, rinse, repeat....I’ll be damned if I can really tell a big difference with my imperfect audio memory and overall lack of patience for this kind of stuff. Ultimately I just want to listen."

That is a good encapsulation of why I've not done this even though I've had the C2500/MC2301s for about two years, in addition to just enjoying the gear with the stock tubes. For instance, my MC2301s are in a low Salamander rack of their own at floor level between the front speakers, but there's a shelf above them that supports my Vox. It probably will be more convenient to take the Vox off that shelf and take the shelf off, then put it back together instead of dragging those monsters out!

Your insights as to what tubes have had more/less impact on the sound is very helpful and will put some things in perspective, especially with the Telefunken and Siemens 12AX7s and your experience with McIntosh. I don't consider my hearing as especially sensitive, and I'm not as articulate in describing what I hear as many on this forum are. Combine that with the range of prices for tubes (10x or more for some brands in production vs. say, Telefunken NOS for 12AX7s), getting your impressions is very helpful as I find a path with my ears, and those of Boss-girl.