McCormack DNA1 options

I own a McCormack DNA1 and a TCL-1 preamp and Merlin TMS-SE monitors[which I really like].

While I have been very pleased with this combo I do find
it, at times, a tad forwards, somewhat grainy, and harsh/tizzy esp. at the higher frequencies.

I listen to a wide range of music, esp acoustic and vocals.
I'm in a position to upgrade and I was wondering how best to invest.

A) Get the DNA1 upgraded
B) Purchase a tube preamp
C) other ?

Thanks for your input