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

Terrible advice to get rid of the speakers . No speakers are designed to sound like what you are describing . Look elsewhere in the system . Start with your preamp . A personal experience last night . My system sounds fantastic .Couldn't be happier . Decided to buy a Krell preamp off craigs for the fun of it . Installed and my speakers are describing what you described . The Krell just does not fit in with what i got going on . Keep at it and good luck to you .

Fyi . I own a pair of Revel f30's and i find them flat and dull sounding next to my electrosats and rarely listen to them .

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 .