Tubes for Conrad-Johnson PV-14 preamp?

It seems I might need two new tubes for my C-J PV-14 preamp. The last tubes I got from C-J about 6 or 7 years ago. The current tubes are 6C4. Any one have a suggestion on other tubes for this very nice preamp? Thanks.
Try this thread :

I had the PV 14A a few yrs back and it came equipped with Mullard 6C4 M8080 tubes. Many think this tube is the best. You might get them from CJ or from Watford valves in England.
Thank you Amarquis.