Re: Favorite Power Tubes. Why?
EL-34.
I have amps with EL-34, 6L6, & 6550 tubes, and used to have one with EL-84s. I've also had KT-88s in the amp that has the 6550s. And EL-34 is my favorite. The 6550s are a close second, but they have so much headroom that you really need to crank them to get them to break up.
And as to why I like EL-34s? I like the way they sound when they distort, and I can get decent cleans out of them with the right EQ settings. Maybe not as sparkly as 6L6s, but that also depends on the brand/type of EL-34.