I think this question gets asked pretty often these days, and sometimes a search or two around the site can be fun and informative.

Unless your DAC puts out less voltage than the optimal input minimum for your amp, you won't get more volume/power from a pre. But pres like the CSP3, that have good sound tuning abilities as well as being a pre...playing with tubes, cables, and gain balancing between pre and amp, it can change the sound enough to feel a little more powerful. I use my pre for sound shaping, balancing gains between amp and pre to tune weight, body, clarity, lucidity.... though part of the volume, not a volume per se... I start in general, optimizing system/room sound, and then little gain tuning adjustments to optimize for recordings that are extra dark or lean or other refinements I get to know from practicing gain tuning. A great tool to me.

If not familiar with this idea, search gain tuning, or gain riding... I think there may be a fair bit about it. It is all fun!

Maybe add a good subwoofer. May help you some for a bit more low end 'juice'. I do have an old Hsu research vtf-3 sub attached to our zenufo. (rca high-level) But, it's turned way down for just a hint more low end on certain recordings. Works great! Love our setup with the UFO!  Our speakers claim 101db @ 1 watt 1 meter. As LOUD as we would ever need in here! Our fairly large front room with 14 foot cathedral.  [smiley=icqlite20.png]