07-10-09: Daniel825This is a rapidly emerging product category. The easy answer is also a bit expensive--the Benchmark DAC Pre at $1595. Small footprint, inputs for RCA and Toslink SP/DIF, USB, and analog. Outputs to XLR, RCA, and headphone jacks.
Does anyone make a line preamp with usb that also has a DAC in it? So that I don't have to use the DAC that is in the Mac?
You could stick with the Vincent and add a small USB DAC between the Apple and the preamp. Possibilities include the HRT (High Resolution Technologies) Music Streamer at $99 or the higher quality or Music Streamer+ at $299.
Another very ingenious design is the Devilsound DAC at $299, which is a USB-to-stereo-RCA cord with the USB DAC in a tiny matchbox size lump where the cable switches from USB to RCA. Very clever and lots of favorable Internet buzz.
You may also want to peruse the product offerings of Nuforce-Icon, which includes a battery-rechargable iPod-sized DAC/headphone amp (Nuforce-Icon Mobile), and the Icon, a little desktop USB DAC, headphone amp, and integrated amp at $249. It doesn't have stereo RCA preamp outputs but you could use its headphone jack to drive the AudioEngines, which only input is a 1/8" stereo jack anyway. The AudioEngines come with a 6' adapter cable. Just plug it in between the Nuforce Icon headphone jack and the AudioEngine 1/8" input on the left speaker.
Stereophile review.