I had 6L6s in my Fender Hot Rod, I liked the clean but hated the dirty. Got my Mesa Roadster, came with 6L6s, liked the clean but the dirty was still lacking. Swapped the Mesas tubes for EL34s and I love it. Punchier, more upper mids, and I can be heard better in live situations without having to play a certain way or on certain settings.