Kek,
The 99 needs about 100 hours of break in time to really open up. When I tried any Sylvania tubes in the Rogue, they just came across as bright in my system. I finally settled on Ken Rad black glass in all 4 slots. I'd suggest using the pair of Ken Rad in the 2 right slots and sticking the Russian tubes in the 2 left slots. I talked to Mark O'brian and he mentioned the layout of tubes inside the 99. The 2 on the right are from top to bottom: right channel amp tube and left channel amp tube. He suggested using the best tubes in these 2 slots. The 2 on the left are from top to bottom: right channel mu follower and left channel mu follower. The two tubes on the right are about 70-80% of the sound while the two tubes on the left contribute 20-30% to the sound. You might want to also call Mark O'brian at Rogue and ask what he suggests for tubes as he also sells sets. Good luck and keep us posted!
The 99 needs about 100 hours of break in time to really open up. When I tried any Sylvania tubes in the Rogue, they just came across as bright in my system. I finally settled on Ken Rad black glass in all 4 slots. I'd suggest using the pair of Ken Rad in the 2 right slots and sticking the Russian tubes in the 2 left slots. I talked to Mark O'brian and he mentioned the layout of tubes inside the 99. The 2 on the right are from top to bottom: right channel amp tube and left channel amp tube. He suggested using the best tubes in these 2 slots. The 2 on the left are from top to bottom: right channel mu follower and left channel mu follower. The two tubes on the right are about 70-80% of the sound while the two tubes on the left contribute 20-30% to the sound. You might want to also call Mark O'brian at Rogue and ask what he suggests for tubes as he also sells sets. Good luck and keep us posted!