Dont know your amp but im sure its a nice one. If your preamp is anything like the XP-10, then its a great preamp. Is it meant to be powered on 24/7 as well? So you have all SS now....what is your amps sound character like? More like a Pass Labs sound, or like a Krell? or something else? Its very much possible to run hybrids that can tame a hot tweeter. But usually when adding a nice tube amp, one also changes other things in the system as well.
Nick - I would at least try to audition the new Zesto preamp. I would talk to George at Zesto audio and see if he has one you can audition. I heard it on TAD's and it was very nice. The search for a proper, reliable DSD Tube DAC may be a while.