05-28-07: NewbeeI noticed just the opposite in the Leben. Interesting. It might have to do with the brand of tube being compared.
Tvad - FWIW, dealing with like kinds, ie SED's, I found the 6l6GC slightly mellow thru the upper mids/highs compared to the EL34 in both of my Primaluna amps...
Thanks for the info on the JJ tubes. Quality control is extremely important. It makes the Osram KT77 tubes at $200 ea start to look like a good value if you tend to burn through bad JJ tube after bad JJ tube.