Best amp for natural timbre of unamplified acoustic instruments & vocals w/ Revel F32?

I view speakers and power amps as a single unit.  The amp drives the speakers - so most certainly the issue could be with the amp.  It is possible but less likely to be earlier in the chain.  Your mission, should you choose to accept it, it to identify the problem (or problems).  Much like cars or health, once you have identified the problem it is then possible to take the appropriate steps. 

I agree with the prior comments: if you want to keep the speakers (and they are good in the right set-up) then a tube amp, which combines the best of both the world of valves and solid state, may be the best solution and one that will accommodtae changes to you speakers in the future.  As I noted in a response to another forum inquiry,  I have the Octave MRE 220 mono's.  In a word they are "incredible".  Octave integrateds may be a lower price option that would deliver a seemless solution at the front end as well.  You can always add the "Black Box" if you later decide to  increase the capacitance of the power supply to drive more difficult loads.

Ray

The speakers had a brand new, just installed titanium tweeter.  They are sounding much better.  I think alot of the dry harshness that I was hearing was the tweeter not being broken in.

For those speakers I would look towards a good quality newer Class D or Class D hybrid type amp.

Something along the line of the Rogue Pharoah or Peachtree's new Nova 300  (integrated amps) or Bel Canto ref600.

I have used older Bel Canto ref1000m amps with speakers having similar challenges for a number of years and remain satisified with those.  A pair of these used would certainly do the job for nominal cost.
  
These amps will do a good technical job of bringing out the best in your speakers.   If that still does not float your boat, then I would look to change speakers perhaps.

if your like me and are always buying used gear off craigslist i would have more than one amp , dac on hand for evaluations . Notice no preamp . 7 out of ten times the preamp is the root of what the op describes in my experience . Now a passive volume control has 100% worked with a dozen amps , dacs , speakers .What works with setup A  might not work when a new variable is introduced .