The JJ E34Ls are just like regular EL34s, but with more clean headroom, which will provide a tighther more aggressive tone.
For preamp tubes, I my self always used either Highgain balanced EH12ax7s or Highgain balanced JJ ECC83S.
I compared both tubes a whole bunch of times and I personally found the highgain balanced JJ ECC83S to sound tighter and "thicker" tone wise, but I guess that comes from their dark type charasteristics. While the EHs have a bit more High-mids to them, which provided crunchy distortion, but I found them to be a bit more noisey then the highgain JJs, and not as "tight" sounding.
I order my tubes from Doug at
Doug's Tubes. Reason I get them highgain graded because I find the off the shelf JJ ECC83S and EH12ax7s to be lacking in the gain, which could possibly affect their tone. I get them highgain graded at 110mu.
gain wise between the 2. They're very similar on how much gain they can provide, maybe the highgain EH12ax7 can provide a touch more gain, but nothing a highgain ECC83S cant provide with a little more volume.
Also, dont let the word dark fool you when people tell you JJ tubes are dark. Its the characteristic they have, but they seem to roll off some of the "harsh" highend off by adding a bit more low-mid to the sound. Its nothing a little addition from the presence control cant fix
EDIT - I forgot to add that if you decide to get some JJ ECC83S, get the un-labeled ones from Doug cause they're like $2 cheaper then the labeled ones and sound exactly the same.
Hope that helps,
Duke
