@mitch2 - Below is the link to Brent Jessee's website page for 12AU7's he gives impressions of the sound of different NOS 12AU7s which may help you match the tubes with the sound signature you prefer
https://www.audiotubes.com/12au7.htm
Best 12AU7 Type Tubes for a Preamp
I am hoping for some help finding good quality and good sounding 12AU7 variant tubes for a preamp – I need two tubes. A price of around $100 each or less would be great but I would pay a bit more (150 ea.) for something that is likely to sound better. The unit came with JAN PHILIPS ECC82 (12AU7/5963) and I also own a pair of reissue/new Mullard ECC92 tubes. Both sets are quiet but I am wondering if there is something even better sounding at a moderate price.
Readily available NOS options I have seen include:
- NOS RCA Blackplate or Clear Top at about $100-150 EA.
- Amprex 7316/ECC186 at around $150 each, and
- Mullard CV4003/12AU7 $150ea.
New options I have found (in addition to Mullard) include (among others):
- Genalex - Gold Lion B749 / ECC82/12AU7, $70 ea.
- Psvane 12AU7-S Art Series ECC82, $55 ea.
Thanks for any help.