The EL34's are the Ruby EL34B STR. I'm not sure who makes the KT66's; the writing on them is "Electron Tube KT66 Made in China". I thing the brand might be Shuguang. I got the first set of KT66's from Cary, and the 2nd from Upscale.
What I mean about the male vocals reaching out, is that they just seem to have more presence, like they are closer to me and a little more gutsy. Maybe the KT66's have a bump in the lower midrange? Anyhow I really like the effect. It actually sounds more realistic to me, like I am more in a concert hall. I had to go back to the EL34's for a while until I got a new set of KT66's, and I thought there was definitely a bit of lost 'magic'. I would love to try a more 'exotic' KT66 like the Genelax, but holy cow, are these expensive!!
Matty, if you decide to try the KT66's, I would be very curious to hear your comments. Be aware though, that you lose a bit of power; I think the KT66's provides around 35wpc as opposed to the 50wpc from the EL34's. No problem for me as I am using fairly efficient speakers, and it goes as loud as I need.
