New tubes for Cary 303T

Any recommendations for changing tubes in Cary 303T?

I now have the stock tubes, but would like to try a warmer alternative where I can hear a bigger difference when switching from SS to tube output.
What type of tubes does it take? I might be able to make a suggestion, if it uses tubes I am familiar with.
Tubes are 12AU7. There are 4 of them.
NOS Mullard's work well. Also RCA clear tops.
Have the same CD Player and asking the same thing. I am leaning towards Gold Lion. Since I have a cary Sli-80 and changed the preamp tubes to gold lion. Blows Electro Harmonix out of the water which came with it. Helps with image, mid range detail Highs Do not Screech and bass goes lower and has more throw in woofer.

was looking at the Cary website moments ago, has Cary stopped making the 303 and 306 CD/SACD players?
No more CD players from Cary. Only DACs.
Thank You! Yashu.
My favorite Old Stock 12AU7 is the Amperex made in Heerlen Holland around 1960. These are truly great especially if you can find real/honest 7316s at a decent price. I also like the Blackburn Mullard tubes for their rich warm tone. I have heard read only really good things about the current production Gold Lion as suggested. Hope that helps . The Heerlen tubes can get very pricy.