I prefer the "Sofia", "Princess" tubes. But the "Tung Sol" are nice as well. I just learned to stay away from the Russian tubes myself....When they go bad? They can go "Really, really, bad"...…. I have the Tung Sol in now. "Very warm" and articulate.. The "Sofia's" evidently, "are just", "Hand-picked" and matched at the factory by some guy from Cali, from another Chinese brand. Maybe "Tung Sol"? Ha ha ha.... But damn they sound sweet! But those Snappers are "Voiced" with the Russian tubes...… Just be careful! Buy a tube tester and learn to use it! And "only", buy matched Quad's for the Snappers K-88's.
Like they say;
"An Ounce of prevention is worth a Pound of Cure"!!
Hee hee, My rig has all the "Punch' I could ever want!!!! Ha ha ha.
You cannot see the three "Martin Logan", "Descent", sub's…. They made a HUGE difference! Far and away the finest sub I have ever heard. Each has three 10", alum, servo controlled transducers and a massive 7600 watt class D amp....
I use the snappers for "Mids" with the triode switch. The other set of Snappers for my "Mid-bass", 85-150Hz. The 'Sublime Audio" active crossovers are truly the 'Trick' though. They are amazing compared to any other crossovers I have ever found! Balanced And Un-balanced input/outputs, so I can switch through components at will. It just takes all damned day!
Now all you need is the Manley, "Neo-Classic, 300B preamp", to play through!