Tube el34

I have used the original Tesla E34Ls for almost 20 years, and still have enough in reserve(not for sale, by the way) to last me for some time. I also have a good number of the later issued JJTeslas, and yes, I have compared the two, and also feel the originals trump the JJs in the areas of slightly greater clarity and top end detail and deeper, more controlled bass. I also have a dozen Siemens made AEG EL34s, which though nice sounding, don't quite give me the balance I like with my original Teslas. At about the time I purchased those Teslas, I tried Svetlanas, but have never listened to the more current Winged C Seds. I attributed the same characteristics to the Svetlanas as Ponnie has to the Seds---not involving enough and lacking top end extension. I have not tried the EH or any of the Mullard EL34s, and cannot use KT77s in my Air Tight amps. Of course, these are my impressions utilizing my componentry. As they say, YMMV.

I recently purchased 2 quad of el34 Tungsol for my prima luna 6 mono blocks, and I am quite satisfied.

I just put 8, EH EL34's in my Cary CAD 120S amp just to try them out. I was using the new issue Gold Lion KT88's previously so this will be an interesting comparison. I thought the Gold Lions were great by the way. Maybe just a little to warm for my Harbeth speakers that are also on the warm side.

NOS Mullard, Siemens or Telefunken rule IMO. OLD Tesla were robust and made to last, don't know if the same could be said of the new. It is a scientific fact that cryogenic treatment is futile unless you use HUGE magnets to orient the molecular grain structure of the metal components in the tube at 0 degrees Kelvin. Something like a MRI scanning magnet should suffice. This orientation that actually does have some performance benefits to electron flow will be affected adversely as soon as the valve is heated in use. I suspect therefore that the benefits would be marginal at best. Aside from perhaps stress relieving the tube. The benefit is I suspect to the tube sellers in the way of value adding.