Warm Sounding Preamp Suggestions


I'm looking to dial down some mid/high glare from my newly acquired B&W 801 S2.  I'm getting a little fatigued and want to see if I can warm it up a bit with a preamp.   Right now I'm using a Yamaha Aventage Receiver and a Threshold S500/II. 

Any suggestions?  Tube preamps? 
dastro
You don't mention your interconnects. They can have a significant effect on sound.

You could try some Transparent cables, before changing out the preamp.
They might mellow some of the harshness. 

  You mention that the your speakers are newly aquired.  Maybe they need some more time to break in and the sound may mellow out some