need help on transparent sounding 12au7 tubes

Thanks for all the great recommendation, this is good information to know, will certainly use these recommendation down the line. I plan to clean the pins of the RCA's this weekend, should I use Silclear on it (silver enhancer)?

I just listened to my system tonight (well rested and everything)and it sounds amazing. This is my second night with the Eklipse and I'd have to say I'm very happy. This pre is very quiet, sweet, slightly forward in the midrange which bring out vocals perfectly for rock albums such as Dire Straits Brothers in Arms, SuperTramp, etc.

Thanks to all.
I've read that the RCA clear top I'm using are considered clear and not tubey. Last night, the system sounds amazing, and my initial feeling on this pre may be wrong, I have to listen more to know if I need to change tubes at all.
As I said in my previous post, all these recommendation is great because I will use them in the future, my listening preferences do change from time to time. FIY, just added pics of the new preamp to my page.