Airport Express optical digital output

Posted by: DavidR99 on 25 February 2013

Hi,

 

I have an AE that is the 'previous generation' when compared to the current one (which has a separate power cable). Mine is 'all in one' such that the entire device plugs into a socket.

 

I am aware that the latest generation Mac Mini has a much improved, low jitter, optical output.

 

Does anyone one whether the latest AE has this same low-jitter optical output, or is it the same as the one that I already have?

 

Thanks,

 

David.

Posted on: 25 February 2013 by Iver van de Zand

Hi David,

 

If I am well informed the AE still generates a lot of jitter via its optical out, being completely opposite to the digital out of the Mini.

 

I have an AE from 2011 and can clearly hear the relative low quality of its digital out, though still good if fed into a proper DAC.

 

Iver

Posted on: 25 February 2013 by Disposable hero
Originally Posted by Iver van de Zand:

Hi David,

 

If I am well informed the AE still generates a lot of jitter via its optical out, being completely opposite to the digital out of the Mini.

 

I have an AE from 2011 and can clearly hear the relative low quality of its digital out, though still good if fed into a proper DAC.

 

Iver


Also the Airport Express of 2012 clearly has a lower quality sound from its digital output, when being compared to a MacBook Pro (2011) that is wired directly into a Naim DAC.

 

Although for casual listening periods, when not seriously analysing some musical piece and only wanting some background music it is handy to switch on the AE and stream to it.

Posted on: 25 February 2013 by mutterback

There is a very good article on this topic - with measurements- here:

http://www.computeraudiophile....ple-airport-express/

 

Conclusion is that 1st generation is actually better, but that neither one is great.

Posted on: 25 February 2013 by RaceTripper

BTW: I discovered last wek that my latest gen. Airport Express has EMI issues with the power cable. I was getting a thump-thump-thump sound on the right channel of my phono stage. At first I thought it was an issue with a secondhand (minty fresh) 282, but discovered it wa there with my 202 as well. I tracked it down to the power cable of the Airport Express. I could even modulate the amplitude by moving the cable around.

 

I have since relocated the device to a different part of the room and use a longer toslink cable to connect to my ND5.

Posted on: 26 February 2013 by Simon-in-Suffolk

From memory the AE up samples everything to 48kHz16 bit which probably has more to do with the mediocre sound. If i have got this right there is almost certain to be rather poor arithmetic errors distorting the frequency spectrum.

The AE comes into its own as a wifi access point supporting multicast which is very useful for optimum use of Nstream.

 

Racetripper.. Glad you got your RFI issue resolved.. As you say best to keep your SMPS away from Naim, however the AE might have a fault in some of its filtering and so might still be polluting your mains.

Simon

Posted on: 26 February 2013 by Eloise
Originally Posted by Simon-in-Suffolk:

From memory the AE up samples everything to 48kHz16 bit which probably has more to do with the mediocre sound. If i have got this right there is almost certain to be rather poor arithmetic errors distorting the frequency spectrum.

The AE comes into its own as a wifi access point supporting multicast which is very useful for optimum use of Nstream.

Simon, I believe the AirPort Express passes 16/44.1 fine though with high jitter.  It's the Apple TV which resamples everything to 16/48 though as a result it does appear it sounds better than the AirPort Express.

 

Eloise

Posted on: 26 February 2013 by Simon-in-Suffolk

Eloise, thanks for correcting me, indeed I must have been thinking of the AppleTV.

Simon

Posted on: 26 February 2013 by likesmusic

I believe there are issues with the stability of the clocks in the latest AEs. If you go over to the pink side, you'll read of problems that the designer of the M-DAC had interfacing an AE to it:

 

" First first Gen worked without Drop outs when set to High Bandwidth... With Gen 3 they changed the Chip set and its even worst then the first for Jitter performance - with large discrete jumps in clock offsets - these jumps throw off (unlock) any dac with decent jitter attenuation (Tight Lock Bandwidths) - ironically Dac's with poor jitter attenuation cope with the Jumps, but off course they have poor jitter attenuation..."


and here's a similar comment from CambridgeAudio, quoted on an apple support forum:


"Basically, the Airport does not output a smooth SPDIF clocking. Every now and then, the Airport will sporadically adjust its output clock to track the desired sampling rate.
These adjustments are very sudden and are the cause of the noises and/or drop-outs describe".