What’s the best tube for a Sonic Frontiers SFL-1 preamp

Hello all,
I just acquired a SF SFL-1 preamp. What’s the sweetest tube any of you SF fans have used in this preamp?
Thanks

skipper32002-13-2021 10:35pm

kmonman Details Discussions Posts This discussion Message User 2 posts 10-01-2021 at 01:56am Copy Comment URL Report Comment Edit Delete Shuguang 12AT7A (Ei), sorry, and right channel went out in 2013, repaired with no further issues. Ordered the tube upgrade kit from the Parts Connection when they were a division of Sonic Frontiers, use the Pearl small tube cooler but never installed the Mullard CV4024 KQDD/K tube...jumped right over it to the 6201. Try either one or I have a tube never used.
kmonman Details Discussions Posts This discussion Message User 2 posts 10-01-2021 at 12:03am Copy Comment URL Report Comment Edit Delete Congrats on the buy. I am an original (1994) owner of an SFL-1 still in use today with 0 issues. The original tube, which I still have, was a Shunguang Golden Dragon 12AT7A ECD-81. The only tube I have replaced it with every 6 years or so comes from Upscale Audio, Cryo treated NOS Mullard 6201 Gold Grade 12AT7. I only think to replace it when the system starts to sound grainy. Never the amp, always that one tube long into its lifespan then falls off quick. Next one will be Cryo treated from Kevin's stash of NOS because I just gotta know. Start with the 6201 at the least.