Replacement tubes for Sonic Frontiers Line 2 SE?

It is time to replace the original tubes (Siemens) that came with my SF Line 2 preamp. The Siemens tubes are hard to find (and pricey). Could some of the Sonic Frontiers preamp owners who have replaced tubes comment on alternatives to the Siemens tubes?

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Unfortunately all real good NOS tubes continue to rise in price as demand becomes greater,and supply dwindles.The Siemens,Telefunkens,Valvos,Amperex are you best bet for the SFI.THe most important tubes are your 2 gain stage ones and you can use Sovteks,or any other less expensive brand for your remaining 2 pair.
My Line 2 came back from up-grade to the SE level with NOS Brimars, and they were too soft and uninvolving for my taste. So I put a pair of Brimars in just the 2 driver positions (gain positions), and used stock Sovteks in the other four positions. This was better than 6 NOS Brimars.

But recently, a friend let me audition a set of six NOS Sovteks (1970s), and I liked them so much I bought them. They were un-used and from Upscale Audio. The NOS Sovteks are distinctly more liquid with more "air", detail, smoothness, and are more holographic than the stock Sovteks-- and also much more dynamic than the Brimars. I've tried other NOS tubes in the gain positons and did not like the (usually) excessive bloom in my system.

I do think it's a system specific thing, and of course personal preferance, eg I like the stock Sovteks much better than the NOS Brimars-- they are much more dynamic, although a little bit dry, IMO. Good Luck. Craig
I've used RCA tubes in the rear most bank and was very happy. They were relatively inexpensive, and came very close to what I got from Telefunken. Also tried Amprex (not sure what flavor amprex, but I bought them new for $45) and didn't notice a difference between them and the stock Sovteks. I'd recommend sticking with the Siemens. Ya get what ya pay for.
My SF Line 1 is currently outfitted with the same NOS Sovteks Garfish references, plus a pair of NOS Amperex 7308 JAN white labels in the gain positions. After trying several others this combination is the best yet.
I used to own the exact preamp as you have now and I remember the best tubes I had on the gain positions are Siemens E188CC with A-frame (best treble extension), and the Siemens CCa A-frame(best bass and mids).
I tried variants of Siemens E188CC and CCa that does not have the A-rame structure and they don't quite sound as good as the A-frame versions. I also tried Telefunken 6922, Ampererex 7308 white label PQ, Amperex Jan 7308's white label,Mullard 6DJ8s and 6922 BVA logo, Valvo white label E88CCs and I repeat none comes even close to the two tubes I described above. Of course this are all just my opinion on how they sound on my system back then.
Hi All,

I have an SF Line 2 on the way.  I will be using it with a ModWright Oppo and primarily listen to digital media. I also recently purchased a Conrad-Johnson MF2275, so there's that....

I am looking for a 'dark liquid' sound.  Not 'warm' or 'bloomy', certainly no glare or blare. A hint 'woody' would be alright. Tightly radiant and/or illuminating would be good.

So what tubes can you all recommend?  

Thanks so much for for all of your shared experience.