What will a preamp do for me?


Missing in the chain below is a preamp - I use the DAC to control volume.  This is my only source and will be for some time.  What could I gain by adding a preamp?

I have Thiel CS 2.3s driven by a BAT VK-55, sourced by PS Audio PW DAC, with bridge II, mostly tidal.  The DAC serves as a preamp in terms of volume control.  Mostly Audioquest cables, amp power cord is Cardas Clear m, all fed by PS Audio upc-200.

I am am hoping to improve the highs, which sometimes sound smeared, too much sibilance; would like more air and clarity.  Loud rock sounds flatter, less dynamic than I’d like.  I am not willing to give up the deep detailed and beautifully resonant mids.  Willing to spend up to $3000, used is ok.  Totally balanced is a must.  Not currently willing to entertain the idea of different speakers - my goal is to make the 2.3s sound as good as reasonably possible before moving on to other speakers.  It’s easy to find a really good preamp in this price range, so much so I am almost paralyzed by the choices.  Aesthetix , Ayre, ARC, several BAT, Parasound and more all have apparently excellent models in my price range.  Patience would put Atma-sphere and PS Audio within reach.  Which is best for my situation?  There’s no way to audition all of these, how could I avoid getting on a preamp merry-go-round?  Or should I spend my money elsewhere?
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A DAC using a digital volume control will result in a worse SNR, which could effect dynamics. An analog pre-amp will keep the noise floor the same regardless of volume.

If just looking for an analog preamp, you don’t need to spend a lot.
Thanks for the insight on why volume control from the DAC causes a weakness in the system.  Eventually I want to upgrade the PWD to the DSD, so that makes the stellar gain fell a non starter, unfortunately.  I will check out the 4.6 pre by ps audio, but I really want to stick with balanced, and so far I have not had much like finding a low cost totally balanced pre.  Schiit Freya?  
Schiit Freya?  
Perfect, you have the choice of passive, tube, or solid state. And it has everything you need.
Still going direct without "bit stripping" is the most transparent/dynamic way of getting the source to the poweramp/s. Some people just don't like the sound of their source so they prefer to color it with a preamp.

Cheers George 
George, 

Count me in the crowd that likes to color the sound. I've had the PS Audio Directstream,  Bricasti M1,  Jeff Rowland Aeris,  and Chord Dave. I tried all of them directly into my amp and preferred the sound with a preamp in every single case. 
Nice recommendation for a Schiit Freya. Will try a such. To get into the tube sound and still be able to switch to a probably more neutral passive volume control. For your sound it may be a good idea to add some room compensation to your system like antimode 2.0 or similar. Cheaper than new speakers or a new room and can give very good results for your bass control and dynamics (from a flatter freq. curve).