Tube recommendation for Audio Research LS-2b?

I'm sure Audio Research would have the best recommendation for you.

Try a Amperex Orange Globe, I always keep going back to them and they are affordable, if you wanna spluge a Telefunken 6922. I have a bunch of OG's A frame Dimple disc and O getters, $20 lemme know if you want 1.

Sovtek 6922 as the original tube in your LS-2 did not sound right to me, so I did a little research and as I suspected the original tube was a Chinese 6DJ8. As I recall it was actually a 6DJ8H. My favorite tube in the Audio Research hybrid preamps back then was a 6DJ8H from Penta Labs. I recall Audio Research explaining the preamp is biased for that specific tube and in order to properly use a different type of 6DJ8/6922 a bias adjustment is required. Without the correct tube or the proper bias adjustments the sound would become dull. Bias is adjusted by changing resistors to achieve the proper settings.

I have a ARC LS22 that I use sometime and use to use the LS2B. If you want a nice improvement and not spend big, try these. They work very nicely in the ARC gear.

http://www.tubemonger.com/Matsushita_Japan_6922_E88CC_Mullard_Tooling_NOS_p/591.htm

These are also very nice sounding in my ARC gear.
http://www.tubemonger.com/Tungsram_E88CC_6922_MINT_NOS_NOV_1973_HUNGARY_p/1108.htm

If you don't mind spending a little money.

http://www.tubemonger.com/Mullard_MPs_MINT_NOS_1967_MIL_7308_CV4109_E188CC_B_p/2000mb.htm

I also like the Amprex 7308's but they also are quite expensive now.