I have more than 200 pieces of 12au7 to roll. The only rare ones such as ECC802, Mullard 10M, & Mazda, I basically have all the other ones including Amperex 7316 D, big O, & small O, but at the end I'm now using the PSVANE 12AU7 MK II which gives me the best results overall musicality and most balanced throughout regardless of type of music. The PSVANE is very reasonably priced. It also depended on your own taste of music and personal preferences. Included in my favorites, Amperex 7316 small O getter is my second favorite then RCA black long plate D getter, RCA Clear top, & some of the organs tubes such as Baldwin, Hammond, & Conn.