To my ears, they have that classic EL34 crunch, smooth highs, crunchy mids and good low end. They don't seem to "fart out" when I crank the master volume to 10 like my previous tubes did. I'm also using the New Sensor Tung Sol 12AX7s in the preamp, this combination really sounds great in my Marshall. Very balanced and pleasing, the clean sound is really good too.
Cheers,
CJ