I was wondering for those that still own this classics, since each day getting quality NOS tubes is harder and expensive. So what i would like to know is which current Company of tubes on the market today(non NOS) you use with your Mesa Boogie preamps "Studio,Quad,.22,.50" or classic Mark "I,II,II" Amps with great results? And if you do cocktails of tubes,please could you post your finds and if it worth the time and $$$ to do so or you think i should stick with NOS forever!! Even if each day the prices get so high and silly that just buying 4 tubes its more expensive than buying the Preamp it self!!..