Hi there, I’ve now listened and analyzed countless 12au7’s (and it’s equivalents) and thought I’d give my opinion on my current favorites.
1st Place Tie: Mazda 6189 Silver Plates 3-Mica and 50’s Valvo Long Plate Angled Getter
*these are somewhat similar to me in that they both have soaring/sparkling top-ends and beautiful midrange. Â Both have lots of detail. Â I think Mazda has better bass and is slightly more precise, forward and transparent. Â But Mazda is also more dry. Â Valvo is sexier and easier on the ears. Â To me, the Valvos are a bit light on the bass. Â Mazdas have maybe a larger soundstage, but Valvo is deeper and more intimate. Â Tie for first. Â If someone put a gun to my head, I’d choose the Valvos.
The matched quad of the Mullard CV491 Long Plates cost me a small fortune. They sound great and were the seated “incumbents” in my reference system. Â It was time to stop enjoying for a second and get into some serious listening with two other great tubes: the CBS-Hytron 5814 and Westinghouse 12au7 Carbon Plates.