Tubes Audio Mirror PP1

I just purchased a audio mirror pp1 in fantastic condition, I had one a few years back had to return it as it was slightly damaged but had a chance to listen to it, and now have it back.My components have changed since then and so has the sound.I know there are 7 tubes inside I believe they are stock tubes.Looking for a little more smoother sound(treble) to compliment my coaxial driver.My speakers are 96db and at the moment can't get the volume control past 1/4 turn even with 40 watts per.I have purchased a pair of genelex gold lion ax7 but as I just found out have all the gain I need, I am ok with that if the sound is smoother.Any suggestions would help and where to place the tubes as there is a phono section in the pre, trying to improve the output.
Thank You.
What power amp are you using? I am guessing that the Audio Mirror PP1 is a tube preamp, correct? If so, it is overdriving the amp by not allowing you to use more of the volume control's range. Try replacing the input pair of 12AX7's with a pair of 12AU7's for lower gain. This should allow you to use more of the control's range, up near 12 o'clock.
Try to find a pair of old NOS 12AU7's. Any from the 50's, 60's, 70's. GE, Sylvania, RCA's will work just fine!
Avoid imitation current production tubes.Nowhere near as good for sound quality and longevity as original NOS tubes! Even used vintage tubes are a better choice than fake Genelex, Mullard, Tung Sol ...
Thanks for the response, I have ordered a pair of cyro genalex gold lion 12ax7,s,but will take your advice and find a pair of Mullard 12au7,s for the input as I have more than enough gain.There are six tubes in the pre so I can use the genalex elswere, I will experiment once I have the 12au7,s in hand.
Power amps are channel island chip amps the original vmb-1 mono blocks 40 watts per.Love these amps.
Thanks for the info, I am aware of upscale audio and they do sell quality tubes, I found a pair of older rca 12au7,s and I will try them with the genelex,  my goal is to soften the treble a small amount and reduce the gain if this happens and I will be happy.I my have to go to a different tube comination or all of the same brand.The radiotechnique look interesting.
Thanks for the feedback.
@hocheye I always mix "lousy" with "lousey" - which can completely change the meaning of the sentence.