Hi Noushy,
Welcome to Audiocircle and the RWA forum!
I hope you are enjoying your RWA-Z1ES-2.5-BAL, and thanks for posting your impressions!
PS: I am currently using Amperex PQ 8416's in mine (this is a 12V version of the 7308, so you need to set the heater voltage switch
on the tube stage boards to the 12V setting) - it is very addictive sounding to say the least!
I also love the Telefunkens in there - but I haven't had time to compare.
I'll have the RWA-Z1ES at RMAF - heading out tomorrow!
Cheers,
Vinnie