I have a dual recto, but felt like I might be able to chime in. I've always sworn up and down that I was a 6L6 guy. However, when I traded my Switchblade TSC off (which has a combo of 6L6 and EL34) for my recto, I noticed he had EL34's in it. Haven't changed them out. I think I might actually prefer them over the 6L6 Mesa's that I have heard. Which is absolute blasphemy according to Mesa gear heads, I know. Just something about those tubes, with the Vintage hi-gain and a Maxon OD808 out front, sounds so right. And the leads sound incredible.