Should I bother with TOS link on Airport?

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Level 2

262 points

Should I bother with TOS link on Airport?

RIght now I have the Airport Express connected to the stereo tuner with routine RCA patch cords. I could use an optical connector, but would it make a difference? I use the set-up for streaming. Before the audio signal gets to the Airport, it has to come in through the router, go through whatever computer is at hand, and then go down the Ethernet cable to get to the Airport. I am thinking that is a lot of places where the signal could degrade. If the signal is only so good by the time it passes through the Airport, maybe the RCAs are good enough. Or not. Should I buy a TOS link cable?

iPhone 5, iOS 8.4

Posted on Dec 12, 2016 7:07 PM

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Answer 1

John Galt

Level 10

155,816 points

Dec 13, 2016 9:25 AM in response to R_55a

Optical cables, being essentially a long piece of clear plastic, are cheaper than dirt. It's the only way to use the Express's digital audio output though, so if your amplifier has an optical input you might as well use it.

Everything is digital unless you use the analog output. Since Apple uses lossless encoding, there is literally no signal degradation until then.

Although the Express's DAC is pretty good, and certainly more than good enough for me, some purists prefer to keep everything digital and tend to favor some other manufacturer's DACs for whatever reason. Usually that reason is to justify their astronomical cost.

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Answer 2

Tesserax

Level 10

158,268 points

Dec 13, 2016 9:49 AM in response to R_55a

To add to John Galt's response...

Short-answer: As John Galt has mentioned, digital optical audio cables are inexpensive. Try both types of connections with a number of sample audio files of your choosing to hear which sounds best to you.

Long-answer: For either 802.11n-generation AirPort Express, audio (WAV, AIFF, Apple Lossless, MP3, and AAC) files at 16 bit / 44.1 kHz are bit perfect from iTunes to the base station and through the base station's optical output port. All other sample rates including 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz are converted to 44.1 kHz and all 24 bit content is truncated to 16 bits.

Both Express generations perform nearly identical with a significant jitter reduction on the digital optical output with the 2nd generation model. On the other hand, both jitter and Total Harmonic Distortion (THD), increased for analog output with the 2nd gen. base station. Using an external DAC may improve this somewhat.

So, if you use a 2nd generation AirPort Express, you should experience better sonic quality using its digital output vs. its analog one ... or by connecting an external DAC if your audio equipment does not have digital inputs.

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