Tubes used in VTL 6.5 II preamp?


Hi -- does anyone know what brand 12AU7s VTL uses in the 6.5 II preamp?  Much thanks.

And if you have/had a 6.5 II and tried different tubes, would appreciate hearing your thoughts.
rblnr
believe the factory installed tubes are JJs. Dont have the 6.5 but do have the 7.5. You may want to try installing some PSVANE T-IIs. most open and 3-D tube I have tried so far.
You're  correct, it is JJs, I have confirmation now from VTL.   

I'll give the PRSVANE's a try, thanks for the tip.