Groove Tubes EL34LS vs SED

I've had the Air Tight Atm 3s for a number of years. I replaced the Siemens AEGs a long time ago, and substituted Tesla E34Ls, which gave me a more extended top end and more life. In time, like many, I made a number of other changes in my system. Several months ago, largely out of curiosity, I reinserted the Siemens tubes. Compared with the Teslas they produced a warmer, airier sound which I found very attractive. Surprisingly, they had a very nice top end as well, and they certainly didn't suffer dynamically. I must conclude that since I had changed the playing field in other respects, those Siemens tubes began singing a "different tune". But, I've temporarily removed them again and put the Teslas back in, since I've been experimenting with alternate approaches to fune tuning. It's nice though to realize I've got this most welcome "ace in the hole". Anyhow, if your Siemens' tubes are ready for burial, then put them out of their misery. Too bad you don't have access to a tube tester. Otherwise, you might want to try the Teslas. I've not heard the SEDs, but based on what I've read, they might not exhibit the kind of top end extension the Teslas have. Regarding your desire for more bass dynamics, that of course is a matter you will have to experiment with. Certain combinations of tubes and cables have given me more dynamic bass reproduction than others. You might want to try different tubes in the 12ax7 and 12au7 sockets of the Air Tights. I've consistently derived great musical satisfaction from Mullard 12au7 "boxplates". Depending on your sound preferences, you also might want to sample pre-war Ei Yugo 12ax7s, Telefunken 12ax7s or Brimar 12ax7s along with those Mullard 12au7s. Another alternative would be the RCA "cleartop" 12au7s in tandem with the RCA long gray plate or long black plate 12ax7s. The long grays might sound somewhat more exciting, and the long blacks somewhat more relaxed but musical nonetheless. As for cables, that's another complex, system dependent issue. Perhaps some Cardas Golden Reference somewhere in the chain might merit consideration. Best of luck.

Sorry. I overlooked the fact that you DO have a tube tester.

Whodiini...Aside from the original TeslaE34Ls I also have JJ Tesla E34Ls which, to my ears, sound extremely good too. You might want to check out the BOI AudioWorks site.

By the way, For what it's worth, I have tried the Brimar 13D5s with my Air Tights. Though they present a very nice sound, I found them somewhat light in the bass (the area you are concerned with). I strongly recommend you try those Mullard "boxplates" in the 12au7 sockets. You might be pleasantly surprised.

Generally speaking, and relative to the other biggies, EL 34s tend to be a bit bass shy, however, with the right match of components, including cables and other smaller tubes like the 12au/ax7s, one can cull some very respectable bass reproduction. I listen mainly to large scale orchestral music and really don't feel I'm missing much in terms of heft/power. More than likely, though, the fellow who drives his car past my house now and then would disagree.