The best 12AU7 tube I've tried and that I'm currently using on my Phono preamp is an English made Raytheon 12AU7 with small and smooth plates.
These are great sounding tubes, very quiet, smooth sounding with silky mids and highs but not overly sweet and very dinamic. I just love them. I bought 8 of them to have some to spare.
You can get them here:http://https//www.langrex.co.uk/products/ecc82-12au7a-raytheon-nos-valvetube-lc9/
Another great sounding 12AU7 tube but very hard to find are Hit Ray (a joint venture on the 60's between Hitachi and Raytheon), they were damn cheap, I paid 16.69 € for two NOS in their original boxes units. They are made in Japan and sound great, not the warmest tubes I've heard but they're smooth, dinamic and dead quiet.
These are great sounding tubes, very quiet, smooth sounding with silky mids and highs but not overly sweet and very dinamic. I just love them. I bought 8 of them to have some to spare.
You can get them here:http://https//www.langrex.co.uk/products/ecc82-12au7a-raytheon-nos-valvetube-lc9/
Another great sounding 12AU7 tube but very hard to find are Hit Ray (a joint venture on the 60's between Hitachi and Raytheon), they were damn cheap, I paid 16.69 € for two NOS in their original boxes units. They are made in Japan and sound great, not the warmest tubes I've heard but they're smooth, dinamic and dead quiet.