[XXII]

Could be a software problem. Try the analog outs and if you get the same problem it could be that something wrong with the software on your computer.

Also, your optical cable is pretty long. I don't think you can run such a long optical cable without degradation. Try a shorter one?

 

[poo]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif As soon as I stop and start itunes it seems to trip it up.

Dirty laser??? Again, seems unlikely to manifest itself in such a way, but possible. Based on your last comment this seems to indicate something more specific to the player itself - odd behavior indeed... not to mention incredibly frustrating!

 

[johnwmclean]

What I’d like to know is if the CDP is fine with cds, then it wouldn’t be the dac would it

?

 

[XXII]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif What I’d like to know is if the CDP is fine with cds, then it wouldn’t be the dac would it ?

Don't worry, it is unlikely to be something wrong with the DAC chip but it *could* be something wrong with the optical input on your 840C. Have you tried analog inputs yet?

 

[johnwmclean]

Quote:

Originally Posted by XXII /img/forum/go_quote.gif Don't worry, it is unlikely to be something wrong with the DAC chip but it *could* be something wrong with the optical input on your 840C. Have you tried analog inputs yet?

I may those cables available somewhere... but have tried the two inputs on the 840c and they’re both afflicted by the same problem.

 

[Rico67]

I don't know , if it was the same trouble, but when i used airport and my computer (under windows ), sound was great, and every 4 minutes there were some saturations during few seconds.
I have never be able to resolve this trouble and now, i connect directely an usb dac on my Hifi, without use Airport.
it's annoying because the sound was great, but too much hazard saturations.

 

[johnwmclean]

Big thanks to everyone for all your help on this

This has been the vain of my life for the last two weeks, first not being able to get optical out of my mac then buying and replacing a perfectly fine airport express...

The optical cable was the problem, an email from the manufacturer today issuing a recall as follows (for anyone who wishes to know the details):

........... issuing a product recall for the following product: Pro Series 10m TOSLINK to 3.5mm Fibre Optic Cable. These Cables have been tested and a problem with the 3.5mm connector has been found which prevents any light source from entering or exiting the cable without being refracted randomly. This problem causes the digital connection to shut down so in some cases there will be no light coming through the cable at all.

This is a manufacturing fault and we are currently working with the manufacturer to resolve this issue. Whilst the cable has a fault, this will in no way damage your Home Theatre, portable or PC equipment. ********* advises that if the cable you purchased is not working then you should return it to us for a Full Refund. However if your cable is working fine then you can still return it but you're more than welcome to keep it and you will still be covered under our Exclusive 5 Year Warranty.........

See it wasn’t just me being totally crazy

 

[poo]

Thought it was likely to be the cable in some way or other... the light bending or being interrupted like that can do odd things. Makes you wonder about the validity of the whole 'bit perfect via optical' debate... I mean for you the noise was an obvious interruption, but what if the light refraction was happening to a much lesser degree? Not bitperfect, not quite right, but would you know???

Glad you got it sorted John!

 

[krmathis]

Glad you got it sorted, and that it was "just" the cable!

 

[johnwmclean]

The saga continues...

New optical cable same problem out of Airport Express, this time a short 1 metre cable.

but... hooking this cable straight into the mac’s optical works fine, no buzzing, no dropouts (the previous faulty cable didn’t work out of the mac).

A while back I sent a query to Cambrigde Audio technical support, in regards to Airport Express>840c here’s their response:

We have been investigating this over the last couple of weeks. Our engineers and those at Anagram Technologies have identified a 'quirk' with the optical output of the Airport Express.

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 noise described.

This is not something which could have been foreseen. Our engineers are however, working towards the possibility of mitigating the effects of this irregularity.

In the mean time, this seems to occur only with a wireless hook up in our tests, and as such, if possible, may I suggest wiring your Airport Express directly, or continuing with your 'quick fix' as described.

As soon as I have a further update I shall be in touch to inform you. Depending on the findings of our engineers, this may take some time.

so there you go, I didn’t want to leave this thread with a false ending, for anyone thats has had or having a similar problem that I did.

 

[poo]

Thanks for the update. This all sounds odd somehow... I know there have been comments regarding the airport possibly not being the bitperfect beast it is often touted as being so perhaps there is something to the 'quirk' found. Would be great to have more info on this should it arise... I have not experienced the same problem (at least not in this way) - would have thought that if it is a general Airport Express issue it would be obvious to all regardless of equipment used?

 

[krmathis]

Yeah, thanks for THE GRAND FINALE!
I have been running AirPort Express' since June 2004, and not experienced any problems or buzzz. Guess I have been lucky.

 

[johnwmclean]

Quote:

Originally Posted by krmathis /img/forum/go_quote.gif Yeah, thanks for THE GRAND FINALE!

Well not quite, till the fat lady sings...

6 FEB 2009
Cambridge Audio:
I have good news to report. Our engineers working in conjunction with those at anagram technologies have devised a solution to this problem.
There is new firmware for the 840C which will allow it to compensate for the fluctuations in the signal from the airport express, this firmware will require to be loaded onto your CD player.

AGHHHHHHHHHHHHHH
(fat lady singing)

 

[poo]

What!?!?!? You're kidding right?!

Nice to know they took your problem seriously, and made an effort to fix it! Well done John - must be a good feeling (assuming you actually have said firmware)

 

[hexley]

I just observed this phenomena, I was able to capture it in action.
I used a Mac mini to stream to AE via ethernet, and from AE piped it to my MacBook Pro's optical line in using toslink.
It seems to happen randomly.
For reference, I have a AE with 802.11g.
If anybody is interested, I can send the file. (I can't attach wave files.)