The only way to find what works best in your setup and to your own taste is to try different tubes -- different brands, vintages, and different tubes for different positions in the amp (driver, input tube, phase splitter). Also, the "flavor" of output tube chosen can determine what 6sn7 works in the most complementary fashion.
My amp came from the factory with RCA 5692s, but, I like so many other alternatives much more. The 5692s sound too warm and shut down on top. My favorite 6sn7 in my current setup is the Tungsol roundplate or copies thereof (French Neotron). These happen to be expensive. They are expensive because these tubes work well in a fairly wide array of setups so they are in demand. Other very expensive tubes I've tried include metal based Sylvanias. The sound was a bit too thin in my system but a friend got pretty good results in his. With a warm sounding amp, like the Meishu, the metal based Sylvanias could work better than with my amps (Kageki) which are leaner sounding.
Still looking for that cheap 6sn7 that does it all in my system.
My amp came from the factory with RCA 5692s, but, I like so many other alternatives much more. The 5692s sound too warm and shut down on top. My favorite 6sn7 in my current setup is the Tungsol roundplate or copies thereof (French Neotron). These happen to be expensive. They are expensive because these tubes work well in a fairly wide array of setups so they are in demand. Other very expensive tubes I've tried include metal based Sylvanias. The sound was a bit too thin in my system but a friend got pretty good results in his. With a warm sounding amp, like the Meishu, the metal based Sylvanias could work better than with my amps (Kageki) which are leaner sounding.
Still looking for that cheap 6sn7 that does it all in my system.