the best SF-Line 2 tubes are they the Sovtek 6922?

Try the Siemens 7308 (E188CC) on the two output tubes, you may like it, very extended top end, the Siemens CCa has better bass but not as extended. The Telefunken E88CC is also excelent but, less dramatic than the first two.
This are just my observation on my own system, of course different vintage of the given tubes will sound different also.

Goodluck Hunting.

Hi Amoss; unlike South43, I like the neutrality of the Sovtek 6922s, and they are available in matched pairs pretty inexpensively from Sonic Frontiers. The stock Sovteks do not have the "bloom" or tube euphony of some NOS tubes, and as South43 noted, many prefer a variety of NOS tubes.

I've owned a Line 2 for near 4 years, and have tried several highly thought of NOS tubes including Siemens and Valvos, but I kept going back to the stock Sovteks. I recently had my Line 2 up-graded to the SE and it came with NOS Brimar tubes-- they are relaxing but soft and lack dynamics. So I put a pair of the Brimars in the V1 and LV1 (gain) positions (the two rear most positions) and Sovteks in the other four positions-- well this did it for me. The Brimars and parts up-grade of the SE added some welcome warmth, while the Sovtek 6922s added dynamics and "liveness".

But the only way you'll know what you really like is to actually try some other tubes and see. www.upscaleaudio.com is a good place to start, but there are others. Good Hunting. Craig

Most anyone who does tube rolling will tell you sovtek are not the best for SF or many others. There are many web sites,dealers, and Agon members who can steer you in the right direction. Good hunting!