Airport Express/Apple TV into DAC vs Mac into DAC

From your question and the responses above, the dilemma seems to be: With a computer there would be inconvenience, but you could get decent DAC without any jitter problems (i.e., the HRT Music Streamer II) for very low price (Better yet, going for the II+). On the other hand, if you go with Airport Express or apple TV, you will need a considerably more expensive DAC to make it worthwile. The Airport Express is subjective to jitter, and Kijanki's point is a very important one. If you go that route, I would recommend a DAC known for great jitter supression such as the Benchmark. Alternatively, you could go for a reclocking device such as one of the Monarchy Audio DIPs, which can occasionally be found here used for about $100-200, along with a less expensive decent DAC such as the Musical Fidelity V-DAC.
Good Luck!

Arni, If signal from computer is delivered asynchronously like S/Pdif (Toslink, coax) then in addition to computer clock jitter there would be cable/system jitter. Jitter supressing DACs like Benchmark are always beneficial but not everybody likes the sound. According to technical director of Benchmark John Siau Benchmark DAC1 was not designed to sound warm since warmth (enhanced even harmonics) screws up sound of instruments with complex harmonic structure like piano or percussion instruments. Here is what he says:

"We designed the DAC1 for maximum transparency. If you want to add warmth, you can't add it with a DAC1. Personally, I do not like what warm sounding equipment does to the sound of a piano. Warmth is wonderful on vocals, guitars and certain instruments, but it beats against the streched overtones of a piano. The overtones in a piano occur at slightly higher than harmonic ratios, and these create beat notes with the exact integer ratios produced by electronic equipment (and speakers). Too much harmonic distortion will make a piano sound out of tune. "

Kijanki, understood and agreed. I am referring to asyncronous new generation USB DACs (HRT Music Streamers), which don't seem to have the same jitter sensitivity as inexpensive spdif input DACs.

The AppleTV has lower jitter than the AE or the Toslink from the Mac, so I would go that route.

There are no DACs that eliminate jitter IME. Some can reduce it a little, but usually at the expense of resampling the data and the associated distortion that causes. If they use one particular upsampler chip and a really good clock, the results can be very good however. Most harwdare upsamplers are pretty bad IMO.

Steve N.
Empirical Audio

Steve, look at this measurement page of Stereophile review. It shows Benchmark DAC1 excellent jitter suppression.

http://www.stereophile.com/content/fifth-element-18-measurements

Do you know by any chance jitter numbers for AppleTV?