I'd like to ever so slightly de-tune the top end on my speaker. Just take it down a slight bit (usually only when above 90db)There are tube preamps that can sound like SS based on their design. They can have a hard top-end and extended highs, or they may have fast rectification and lack the tube qualities to pair with your amp.
So you'll need to choose wisely or audition. But I agree to try using a tube preamp.