Primaluna Prologue Two


I have just purchased a Primaluna Prologue Two Integrated and I must confess that I like what I'm hearing so far. The world of tubes is new to me and I have heard so much about how one can tweak the sound by rolling tubes. My first question to which I hope to get a straight answer to is?. Are the Primaluna tubes that come with the unit bad to the point of warranting a complete tube change. Looking at the Upscale Audio site under tubes the primaluna tubes are on par with many others in so far as price. Second question if there are any owners of the Prologue Two what tubes have you changed and what have been the benefits of the change, also what tubes make the biggest difference. I will eventually like to change all of the tubes but not at the moment, so were do I start and get the most sonic improvement for my investment.
Thanks
rossq
Thanks for all the replies. The Prologue Two came with KT88 and a friend has some EL34 which I borrowed and tried. I prefer the KT88, fuller sounding to my hears anyway. I will try rolling the preamp tubes first and take it from there. The unit in question was a store demo so I'm not sure how many hours are on it. I will probably wait a month or so before making any changes.
The 12AX7's that come with the PrimaLuna are very good; however, I would replace the 12AU7's with NOS RCA black top or clear top. I recommend Brent Jesse if you don't already have a "tube monger". In my opinion, NOS tube should be bought from "tube mongers" only.

The tubes I recommended are best for jazz and female vocalists. The tubes you select will be whatever is best for the music you like.
Leersfool, the poweramp's job is to duplicate the signal it's fed from the pre. If you improve the performance of the pre, the amp is supposed to duplicate it. Since power amps are closely related to the speaker, I believe speaker amp synergism accounts for the biggest difference there.
I would burn the amp for like 100 hours at last to begin with. After that change all that shity tubes that she came with.

You will be shocked hou PL2 sounds like after tubes upgrade, its much lifelike, controlled, musical and all that.

I highly recommend NOS Mullards 1950-60's made 12au7 and 12ax7. As for KT88, the best are NOS GEC KT88 or EAT made. The best EL34 are NOS TESLA and Mullards.

If you can effort, go for the best.