Which tubes to roll

I found a good website with an explanation of the evolution of the these tube types, the hows, whys, and what-nots.

http://www.jacmusic.com/KT88/kt88.htm

That's a good link(thanks)!! His observations on chinese business ethics(there's a stretch) and manufacturing, mirror mine. BTW: If you like transparency, nice freq. extension in both directions, and liquid mids- The Winged 'C' 6550C's(latest iteration/St Petersburg plant) that Kevin sells are working very nicely in my Cary monoblocks. I was a hardcore NOS tube addict, until the cost of matched quads/octets of anything decent in power pentodes became unrealistic(Dom Perignon taste/grain alcohol budget). Uncle Kev came through, in style. You could say I'm a happy customer. Does it show? (http://www.upscaleaudio.com/SED-quotWinged-Cquot-6550C_p_16.html)

Tubemonger.com is a nice organization to work with. They may not have the rare and hard to find, but their webpage and service are customer friendly.

If looking for the "power and bass" of the kt-88 with the midrange of the el-34.Try the Gold Lion re-issue.