PrimaLuna Prologue 5 and tube upgrades


Coming from the pro audio world and sitting most of my career in front of extremely flat loudspeakers in acoustically treated rooms, I'm a bit concerned that my brand new Prima Luna Prologue 5 tube amp is quite rolled off from 10k on upward.
I'm sure most would call this "warm" and the typical tube sound, but I would just call this in need of a pink noise generator and a eq adjustment. I am in love with the 3D dimensionality and the incredible soundstage from this amp, but am left craving the pings of cymbals and the air of vocals on playback.
So far, I've only just replaced the 12ax7's with some 70's phillips that I had around. It helped just a small bit with the extention of the highs. Should I chase this down with some great Telefunkens etc? or go back to a solid state amp? Yes, I'm calling Kevin from Upscale later today!
jmacinnis
Thanks gents.

Wescoman...your advice to speak with Andy at Vintage Tube Services was priceless and Brad, He pointed me to the Bugleboys like you have in your PL5. Also, very curious about your "supertweeters"?
Their website was truly interesting.
Replacing 12AX7s with "preferred" 7025s from the tubestore added some sparkle to my amp at an amazingly low cost. Same with some JAN Philps 12AT7s. I like it when a company recommends LESS expensive options that may lack the collector buzz (and prices) but still sound great.
I ended up with Bugle Boy's NOS from mid 1960's from Vintage Tube services. It really did add a bit of 12k upwards back to my setup. Also, the imaging and soundstage seems a bit more interesting and enveloping now too.
After one of my JAN Philips 12at7s decided to commit Hari Kari it was suggested by Thetubestore I try the Mullards, and they're on the way.
so i broke out the audiotools and a DPA microphone through my apogee/mac interface. I pushed pink noise through the RTA and found that there is nearly nothing getting through over 18k. Tonight, I'm going to bring out my old yamaha amp and see if it the Prima Luna/Van Alstine combo or the speakers doing this to the signal. ugh.