My friend borrowed a pair of brimar 6sn7 Gty's from me and said they sounded great in his Rogue.
All the tubes mentioned are very nice. Which tube sounds best will depend on synergy with the rest of your components, not just your preamp.
I have all of the finer 6sn7s. Changing just one component most of the time,warrants me to change out the 6sn7s in my preamp for better synergy.
So,what works best in someone's 99 probably won't in someone others IMHO.
All the tubes mentioned are very nice. Which tube sounds best will depend on synergy with the rest of your components, not just your preamp.
I have all of the finer 6sn7s. Changing just one component most of the time,warrants me to change out the 6sn7s in my preamp for better synergy.
So,what works best in someone's 99 probably won't in someone others IMHO.