Highest Fidelity Audio Systems - Precision Selected Vacuum Tubes. Upscale Audio has been a player with high-end audiophiles for decades. We have the largest stocks of NOS (new old stock) vacuum tubes in North America. Probably the world. Not only do we have the largest stock of vintage tubes, we also sell the finest brands in high end audio including such names as Sonus faber, Manley, Nordost, among others. Finally, Upscale Audio imports and distributes PrimaLuna, the hottest and best reviewed name in vacuum tube audio.