EL34 & 6L6 characteristics

David, most 6L6 vs EL34 comparisons EL34 come out the reverse of what you listed. Then again, EH tubes often sound among them most lush in the spectrum.

Generally, I would stick with the EL34, but try other brands. JJ E34L will come across a lot more as you described the 6L6, and in the right amplifier put forth an absolutely glorious midrange that almost nothing else compares to. JJ and Shuguang EL34 will track closer to what you described the EL34. These three tubes will come in at quite modest cost. EH 6CA7 will present the most slam, though in an easy to live with presentation. Shuguang Black Treasure and old Mullard do sound a better than the others, though at a higher price.

Of course, the amplifier itself plays a role. Your PrimaLuna features autobias, which provides a lot of convenience, though some implementations do not yield as much sonic flexibility as others. I've not lived with a PL amp, so I don't know how they react. With an amp where you adjust the bias, you can sometimes better dial in the tubes to your taste.

David, yes an EL34 should normally sound more upfront and sunny than a 6L6. 6L6 generally sound more lush and romantic, which many prefer in this day where components run more forward and/or lean even if today's high-end audio tube amplifier manufacturers rarely employ it.

You might want to give your Shuguang EL34 a 50+ hour try out. I find Shuguang tubes quite underrated, perhaps because of their low price. In my experience, their standard 12AX7, EL34, KT88, and 5AR4 represent the most rugged current production tubes. So, I'd have no fear in swapping them in place of the EH.

As you mentioned, some JJ variants do have a somewhat deserved reputation for failure; the E34L included. Still, I would not worry about yours since they test well. But again, try the Shuguangs first, and see if they begin to step in the direction you are looking to move. The JJ E34L will not sound as full or as even handed from top to bottom as the Shuguangs, but often present a more notable midrange.

I didn't live with Gold Lion KT77, but they're a tube to consider. I never liked the JJ variant as much as most did when they came out. Depending on the amplifier and system, I prefer either the JJ EL34 or E34L, but their KT77 always places third in the race. I have a quad of the big bottle 6CA7, but haven't tried them. I do like the EH 6CA7 tremendously, even though I have a pretty strong dislike of most (too harsh) Sovtek and (too muddy) EH tubes.

Again, I don't know enough about your amplifier to determine how it reacts to its output tubes...

David, no matter what anyone claims, everyone gets the same tubes from the Shuguang factory. They do not release better or worse versions. When they pass QC, they're good tubes. Again, in my experience, Shuguang produces the most rugged and reliable tubes currently. As you noted, once they go off into the world, various entities screen their own names/logos on them.

If you decide you like the 6L6 sound best, go with it!

I'd still give the Shuguang EL34s a try, just to see how you like them. Normally, I need to listen to 2 or 3 variants before passing judgement on a tube type. EL34 should normally provide good detail.

By the way, I presume you own the Shuguang EL34B variant? You can tell by the fact that they have a reddish brown base. Their original, EL34 (EL34A) have a black base, and do not sound nearly as good.