boris_the_spider

OP here. I got by with the old AEx G for a couple of years on my ESS Sabre DAC. This DAC could not sync reliably to the AEx N. My other DAC could sync up to either AeX, G or N. But the old AEx G would not work with my newer Apple laptop and later SW so for a while I could not stream, went back to CDs. When the new square box AEx came out I bought one but my ESS Sabre DAC could not sync to it. So I did some googling and read PeachTree recommends the Apple TV due to its lower jitter, so I exchanged the new Airport Express for an Apple TV. My DAC is not a PeachTree but uses the same DAC chip. My ESS Sabre DAC syncs fine to the Apple TV and furthermore the Apple TV is much simpler to set up, and it has a full sized TOSLINK out not that mini TOSLINK out. Several people advised on the Apple TV in this thread - you guys were right. Anyway, problem solved.

OP here, I have some update on this, finally had some time to spend on it. I borrowed a scope from work and set about trying to debug this. In the meanwhile I've acquired another DAC so now have three DACs to switch between, and can easily switch between the two airport expresses n and g with any of the dacs. The new DAC also did not sync reliably with the N but worked fine with the G. And my first DAC still continued to sync no problem with either the G or the N. So one DAC has no problem with either and two have problems only with the N but fine with the G. So using the scope I evaluated the jitter and to me there does not seem to be any kind of jitter problem with the N. In fact the jitter appears to be identical to that of the G and it's very reasonable - about 1% of the bit length. In fact, my CD transport had more jitter than the AEx G or N. The signal integrity looked very good to me and jitter was good. No difference I could fathom and yet different behaviour at two of the DACs. I did not analyze the spectral content though. So I spent a couple of hours trying to debug why it was consistenty dropping in and out with the N but never with the G. Won't bore with the details but did not find the reason without being able to look at and evaluate the frames and look for perhaps incorrect headers or something, but with just a scope could not do that too easily. So after a while I got kind of frustrated because I was expecting to be able to debug this. Then I had a look at both Aexs using the Airport utility and I noticed my N needed a firmware upgrade, which I did. After that it worked fine and since then I have not had a problem. The DAC has never lost sync with the AEx.n after the fw upgrade. I also did extensive back and forth sound comparison between the n and g in my system using my DAcs and to me there is no difference in the sound quality. So in conclusion I have to say, to the extent of my own brief evaluation, there does not appear to be a jitter problem with the n. And unless there is a difference in the bits themselves i.e. one not being bit-perfect then i kind of doubt one sounds any different than the other. But I still do not know exactly why it has worked perfectly after the fw upgrade unless there was some issue with some frames before the fw upgrade, or some other reason, any ideas? It's a bizarre result considering it worked fine with one of my DACs before the fw upgrade.

>Boris, are you using the AE's wirelessly? >Perhaps your issue is compounded by an unreliable wireless signal. >I use my airports to play music via ethernet cable. The wireless is enabled to >allow my laptop to VNC to my music server. Codifus, Yes, I'm using the AEs wirelessly. I don't believe I'm having a wireless network issue for several reasons: my wireless network otherwise seems completely reliable, the distance is small, there is not much else going on on the network, and most importantly there are no issues of lost sync when I use the older AIrport Express. I can go with a server that is directly attached and VNC in as you mention but then I have to buy the server too. >I agree that if you're losing clock sync, then it's likely not jitter but >connection troubles. Flohmann, the reason I don't think it's a physical cabling or cable connection problem is that it works fine with one AEx device and not with the other. The cabling and interconnects are the same, the only thing changing is the revision of Airport Express.

>Anyway, it's really sad, that you make your choise between two devices never being compared them face to face, and pick the wrong one. You particular sync problem was not about jitter. I have both the g and the n and have compared them face to face. I also have two DACs. One DAC can sync to both the g and n AEX, the other DAC can only sync reliably to the g. It is just as reported by others (including some DAC manufacturers) with other DACs that can only sync reliably to the g and not to the n. Many DACs will be able to sync fine to the n. I was fine using the n with my first DAC.

Sorry everyone, forgot about this thread. Anyway, I do have an update: I received my ebay purchase of a used 802.11g AEX (Airport Express) on Wed and immediately put it to the test and can report the same finding as reported in multiple places elsewhere: that is that it fixed the syncing problem to my DAC that had regularly lost sync when fed from the new AEX.n currently being sold. This strongly suggests, as others have said, that the older g version has less jitter. I also noticed a changed sound quality which was a more solid or robust quality. After 2 days I have never lost sync to the DAC using the years old 802.11g version, which I only paid $50 for on ebay, half the price of the new one. Still, it will kick most routers down into 802.11g mode as a drawback. To the posters above who suggested the Mac Mini, yes, I've thought about doing this, with NAS, and have considered many other solutions too. To the guy who said the AEX.g uses the USB path, this is not correct. The USB is not functional for music on the AEX, either rev.

You can find a lot of threads on the subject if you do a google search. For instance: http://www.audiocircle.com/index.php?topic=72820.340 Personally I am using two DACs with the AEx-n. One syncs to it no problem, the other doesn't. And the one of mine is not any DAC mentioned in the link above. Regarding the audio output: a couple of posts back you appeared to be talking about the audio output when you said the G sounds a lot worse than the N. If you didn't mean the audio output then could you suggest why a DAC fed off the s/pdif stream might sound worse with the G than the N as you reported. Anyway I did see somewhere the G fixed one guy's sync problem and so I will be getting one any day courtesy of UPS, so will see how it does, and will report back. Also, if it comes down to it I should be able to measure the jitter and report back, if I get around to it.

If you are talking about the audio output of the 802.11n AE - it sounds really terrible! As far as the jitter on the optical output - it's pretty well documented the 802.11n AEX has high jitter, but I've never seen an actual measurement. There are a couple of DACs that don't sync to the 802.11n AEX. That's pretty indicative of bad jitter. One of my DACs syncs reliably to it, another not so well. I bought a g version a few days ago so will see how it does. I did see on some other forum the g version fixes the issue and the original g version is supposedly very acceptable jitter.

Hey Tony, I was looking at the Monarch DIP too, at $200 new. Did you have any problems syncing into the Levinson before that? Are you really sure the Monarchy DIP improved the sound you hear?

I never understood how you can upsample 44.1 to 48. They are not perfect multiples. At some point the 48 KHz clock will sample the 44.1 KHz data twice in one clock cycle. At that point it will not be a bit perfect upsample. Am I missing something?

Steve, I realize the Squeezebox Touch has good jitter but what I'm asking is if there are any current Apple products that have acceptable jitter. Now I know you guys make the Pace Car to reclock it but it's a bit out of my budget. It seems a shame a $99 product (that used to work fine...) might require a $1200 fix. Doesn't Apple make anything usable by itself, that I could use instead of the Airport Express? And I knew Sonos had high jitter but worse than the AEX? The ESS Sabre locks to Sonos but not to the AEX, or so I understood. thanks BorisTheSpider

I'm streaming ALAC files via iTunes over a wireless network to an Apple Airport Express, then using the optical TOSLINK output to a DAC, either using the optical input of the DAC or first converting to electrical spdif. It's widely known that the Apple Airport Express has very bad jitter on the digital output stream, and some DACs are known to have problems locking to it. Does anyone know of an Apple product I could use instead of the Airport Express, that would have more acceptable jitter? The old Airport Express - the rev G - is one option but that's an old product. I could go to Squeezebox or Sonos but first want to see if I can just replace the one piece of gear. thanks