Apple Airplay Sound Quality

Single hangup with the AE is HUGE jitter. Some DACs, my 840c among them, simply do not like this amount of jitter, and have audible problems.

Sterophile had reviewed the first iteration of the AE and found its analog output to be somewhat lacking but as a transport, it achieved reasonable performance.

I am somewhat surprised to hear about the jitter issue via the optical output as mine works perfectly fine as did Stereophile's test unit.

It does play CD quality recordings without any issues but I will give a quick experiment this evening to see if it will do anything higher out of the optical output.

The results of the quick test I took was as follows.

I sent a 24/96 file via Airplay to my receiver with integrated DAC, an HK 3490. The end result was the display stated the signal was 44.1Khz PCM. I can only assume that there is some down sampling during the process, but I do not know exactly where.

I will prepare some more testing to gain more clarity on the matter but I would not be surprised if what I found was additionally confirmed.

I thought the stereophile test measured large amounts of jitter?

I know my 840c simply doesn't like the optical input while the analogue output of the AE is only OK. But, in this case convenience trumps ultimate quality.
My lossless files transmitted in this fashion easily best the MP-3 / 320 or so stuff off the small dish / sirius feed.

http://www.stereophile.com/digitalprocessors/505apple/index.html

Look at comments associated with 'figure 7' for detail