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My PC Audio Question Journey

I finally took the step of getting an external DAC (Maverick D2) allowing me to stream iTunes from my computer via an Apple TV. So far, I have only used a PC, but purchased a Macbook Pro over the weekend that will become the primary computer in the near future.

My system is the following:
Computer with iTunes (Apple Lossless)
Apple TV
Maverick D2 DAC (tube and solid state outputs)
Yaqin MC-30L amplifier
Focal 836v speakers

As a baseline, I have been unable to tell a difference between the solid state DAC output and my Elite SACD player. I am also aware that the Apple TV streams 48 kHz instead of 44.1 kHz which, in theory, is weakness in the digital signal.

Overall, I'm satisfied with my current sound, but I could be convinced to upgrade the Apple TV to an Airport Express and also to use a parallel software that works with iTunes (as long as Airplay is still supported) if I was convinced that an objective improvement could be expected in my system.

There's several layers to the discussion so I thought I'd ask my questions one at a time in an effort to keep things focused.

TOPIC 1:
The goal when ripping a CD is to create a "bit perfect" digital copy on the hard drive. Should it be expected that using iTunes will achieve this goal? If not, is there an objective way to validate that another software performs this step better? Is the primary reason that most recommendations are to not use Apple Lossless vs. other lossless formats is because it is propriatary to Apple making it the most limiting format in the future?
mceljo
kijanki's avatar
kijanki
4,432 posts
 
I use Itunes with Airport Express for playback but MAX on the Mac for ripping. Conversion 44.1 to 48kHz on Apple TV is audible, according to few threads here but Airport Express is a little bit jittery. Is not an issue for me (with Benchmark DAC1) but you might look for jitter suppressing (reclocking)DAC or stand alone reclocker.

https://wyred4sound.com/products/digital-converters/remedy-reclocker

I'm not sure what format is used with Apple TV but Airport Express uses, AFAIK, ALAC. Storing files in different format would force computer to do additional conversion.
doggiehowser
672 posts
 
The file format is irrelevant to Airport Express or AppleTV - as long as iTunes can read it. It streams it as a PCM stream across wifi. It could even be MP3 (shudder) which gets converted to PCM on the fly for transmission.
kijanki's avatar
kijanki
4,432 posts
 
Airport Express is connected by Wi-Fi and as such does not receive in real
time. Itunes/Airplay does not transmit PCM. Computer transmits ALAC data
in packets that are stored in AE in a buffer containing about few seconds of
music. Timing is added from internal AE clock (resulting in 258ps peak-
peak jitter) and S/Pdif PCM stream is created. In order to use format
different than ALAC computer would have to make on the fly conversion
that would not affect the sound since transmitted is data without any
timing.

read this discussion on APPLE support forum:

tstart=0>https://discussions.apple.com/thread/3339297?tstart=0
doggiehowser
672 posts
 
Interesting. Was not aware that they used Apple Lossless. Still the original file format isn't really relevant - they could even be MP3 as I said.

I still prefer to keep everything as AIFF in my library.
kijanki's avatar
kijanki
4,432 posts
 
That's the beauty of the network bridge - computer, playback program etc make no difference since no timing is involved. PCM stream like S/Pdif coming directly from computer to DAC can be affected since computer creates timing.

Timing on the DAC side is recreated with new clock. AE is a little jittery and limitted to 16/44.1 but there are better choices. Logitech stopped making Squeezebox Touch but Sonos makes Wi-Fi Bridge.
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