First, STAY AWAY from Russian tubes & Chinese (line level small signal tubes & driver tubes). They're ALL CRAP when compared to a good NOS tube. Old Russian mil-spec tubes are just old crap. Hey, anybody want to buy my pair of Private Reserve Russian mil-spec NOISY 6SN7's? These tubes are also being sold at an OBSCENE profit, from what I've heard! Yeah, buying power tubes, go Russian, since the cost (and shorter life span vs. small signal tubes) makes NOS tubes all but prohibitive. And the greatest influence on audio quality comes from the small signal & driver tubes, NOT the finals (power) tubes. Upscale Audio appears to have shifted their business strategy. Now, it appears that they are primarily sellers of audio equipment, with a secondary purpose of selling tubes to the general public. Good NOS tubes are set aside for customers who have purchased tube gear from them. After learning the hard way, I discovered Vintage Tube Services. The man to whom you want to speak is Andy Bowman (www.vintagetubeservices.com. Tel. # is 616-454-3467). You'll definitely be impressed. Since he is a one man operation, it's best to CALL, not email, but definitely check out the website! He is the one who also told me about the "dirty little secret" concerning Mullard tubes. Many later production Mullards are actually rebranded Brimars!!! Good, but they still ain't Mullards. However, you still get charged the Mullard price! Take it from one who learned the hard way! And don't waste your money on Cryogenically treated tubes, especially with the jokers who use carbon dioxide (CO2) as the cooling agent. Happy Tunes!