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. Both have lots of detail. I think Mazda has better bass and is slightly more precise, forward and transparent. But Mazda is also more dry. Valvo is sexier and easier on the ears. To me, the Valvos are a bit light on the bass. Mazdas have maybe a larger soundstage, but Valvo is deeper and more intimate. Tie for first. If someone put a gun to my head, I’d choose the Valvos.
Second Place: Amperex 7316 Long Plate Foil Getter
Amperex 7316 is almost perfect but it has some issues in the upper midrange and treble in my opinion. I little bit of sibilance/bloat that becomes irritating. Just this certain frequency range that it can’t handle without distorting a bit. Other than that it’s perfect. The lifelike thickness of notes/instruments, the balance, the soundstage, the flow, the warmth, the seductive vocals. I would have never noticed it’s flaw if it weren’t for Valvo.
Tie for 3rd: 50’s Amperex Long Plate Foil Getter (Bugle Boy) and Sylvania 5814 3-mica
4th Place: Siemens Chrome Plate Halo Getter
5th Place: Westinghouse 50’s Carbon Plate
6th Place: Mullard CV491 Long Plate Square Getter
7th Place: 50’s CBS 5814
Honorable Mentions: Mulllard CV491 Short Plates, Amperex Short Plates, Tesla ECC802s, Mullard Box Plates – these were all tubes i enjoyed at one time, and are significant upgrades from stock tubes, but don’t have knock out characteristics
The Rest: RCA Clear Top, Anything RCA, GE 6189 Black Plate, Tunsgram ECC82, Other Sylvania – to me, these were 1 hit wonders in that they maybe have 1 special characteristic but the rest of the tube didn’t impress enough to leave in