GT E34LS

Wow! What a difference from Mesa stock EL34. My Ace 2x12 with Heritage g12h30's has more balls due to the tightness of the low end and tamed the high end in the process. This is a great tube! I have tried the GT EL34M in my Ace and the low end was rounder and somewhat flubby. Those sound great in my friend's Silver Jubilee though. Clean crunch with the E34LS is punchier. I get a good AC/DC tone here. Channel 2 tight gain is just mean as hell. The low end really hits you and the clarity is glorious! Spongy mode with Rectifier Tube is where this amp shines now. I also put a 5751 in V2. Try it.

Arent these the JJ E34L? If so, I agree. Great tube for the stielttos 8)

Structurally they are different. Tone wise I wouldn't know. I never tried the JJ's.