iMac to nDAC - SYNC

Andy

Have you checked the settings in Audio MIDI?

Thanks for the reply James - yes checked Audio Midi and can't see anything there.  I have tried changing Sound Effects tab (from System Preferences / Sound) to playing computer alerts either through internal speaker or through the V-Link but no difference.

something in the chain, probably the Mac OS, is resampling things or converting.

Thanks PCS.  The only thing I can think of that is different to the demo I had is that rather than taking my external hard drive with me, I copied some music files to the iMac hard drive.  I'm just hoping that I don't have to transfer 157Gb of music from an external drive to the iMac to make this work properly, if nothing else I don't want to clog up the Mac's drive.  

Almost relieved to say copying 192/24 tracks to the Mac's hard drive has made no difference, the nDAC still drops the sync.  Completely stuck.  TIme to phone the dealer / Naim.

Have you tried any playback applications other than fidelia ? Itunes/bit perfect via a v-link has no sync issues on my mini-ndac with hi-res alacs.

Thanks Deeg.  I've just tried Amarra and that's done the same as Fidelia and Audirvana.  Didn't think iTunes could handle hi-res files?

Thanks for that.  Very odd result.  The V-Link is now telling me it is receiving a 192khz signal when I know it can't be unless the Mac is doing some upsampling trick.  The nDAC is showing it is receiving a HD signal but the sync light doesn't want to know at all.

Apologies, by up sampling I obviously meant upscaling.

I think at least part of the problem is a dodgy cable.  I bought a Chord Signature interconnect between the V-Link and nDAC which is ex-demo (still £150) and just found that by moving the cables I either get double lights (sync / HD) or no lights.  Whole thing might be as simple as a break in the cable.  Disappointing if it is that nevertheless.  Will investigate further on the morning.

how about this....  Install Win7 on Bootcamp.  ALL problems solved.

I run external USB hard drive in, FireWire out to Weiss INT 202, Nordost white lightning to nDAC using Audirvana with all the optimisation settings selected (memory play, OSX meddling disabled etc) And Mountain Lion.  If Vlink is USB in then your hard drive should be FireWire/thunderbolt.......ideally.

No problems with HD.  The OS is not the problem per say, not to say that changing it will not solve a problem up the chain If say for example your V link does not like OSX.

Ps.  Have you tried a USB stick with cd and HD tracks mixed up, that should test how the DAC is handling things.

i would not have windoze on a Mac useless you have antivirus on your machine ( I download music from online vendors using my MAC, nothing dodgy but the machine is still net connected.  It's a low risk  machine but its still in cyberspace)

Thanks for both replies Briz.  Will the nDAC play tracks on a USB stick given its a DAC not a streamer/server?  I've tried my iPhone on the USB which works fine but thats not got HD tracks on it.  Normally I use my iTunes library for AAC standard for iPod (car) / iPhone, and the external hard drive for full quality files for my hi-fi. 

Briz - tried the usb stick but as I half expected nothing happened due to there being no player.  I'm back to thinking there are possibly one or maybe two issues -  firstly I think I've bought a cable with a dodgy termination at the BNC end.  I'm not sure however whether that would affect data rate - you would expect it to either worok or not - still want it checked out.

The second point about data rate fro the Mac to the V-Link - I was under the impression that USB 2 data rates were on a par with Firewire.  Nevertheless I am using a 5m run of usb cable so this might be an issue.

As I understand it, the  sync light on the nDAC  should come on when the incoming data is sufficiently close to one of the nDACs selectable master clocks for the nDAC  be able to buffer the data and completely reclock it. (see the white paper). In which case if you aren't getting sync, it implies to me that the clock in your V-link is off when higher sampling rates are involved. I would try a different V-Link, and/or a different source of known quality.

I'm pleased to report a significant update to this post.  Firstly, a big thank you to Maurice of Music Matters, Birmingham who visited the house today complete with enough kit for us to systematically replace every component in the music chain, one piece at a time.  We started with the usb cable from iMac to V-Link, then the V-Link, then the nDAC itself.  We had already tried audio files whether on my external hard drive or Mac internal hard drive to eliminate that (as well as different software music players).  Finally, we even replaced my iMac my my MacBook Pro and still the same issue of the disappearing sync light continued.  We were then left with just the audio files themselves.  We had been focussing on the sample rate to see if it was a data transfer issue for the larger files and it finally became apparent that files acquired/downloaded from stores such as Naim / Linn played absolutely fine, but the great majority of my hi-res files (including all of my 192khz files) had been purchased from HD Tracks - it is these that have the problem.  I don't know whether the files are inherently unstable, or whether the download process has somehow corrupted them, however until I can exchange e-mails with HD Tracks themselves, I'm treating that source of music files with great caution.  Has anyone else had any issues with HD Tracks?  Is there a way of checking the quality of the files (as you can with some ripping engines)?

Hi Andy,

Interesting results: HdTracks - music gives different results than HiRes material from Naim/Linn. I also do not knwo why, but am greatly supprised that apparantly there is a difference. Will keep following this thread. Please keep us updated !

Iver

Andy, from what I've read, you won't get any satisfaction from HDTracks themselves.  But you can try.  I understand that their response is almost always, "We pass on the files we get from our suppliers."  That's it.

How about trying to convert one of them to a different format - WAV say - perhaps there's some metadata that upsets something.

Bart

To be fair to HD Tracks they have responded quickly and have offered to re-enable download - albeit they have not been able to offer any suggestions as to what might be the problem.

Likesmusic - I'll give that a go.  I have not tried ALAC files so thats a possibility.

On disappointing development is that the problem downloads have actually spread - not just HD Tracks but also Bowers & Wilkins Society of Sound (Peter Gabriel 48khz) and, of all people, Naim Label's Antonio Forcione and Sabina Sciubba (Meet me in London 192khz).  I have therefore downloaded Norton AntiVirus and run a scan and run Disk Utility but both came up blank.  I am going to try downloading files to my iMac internal hard drive to see if that makes an improvement.  Its suddenly looking quite random again which is worrying.  I shall keep you posted.  

Any ideas greatly welcomed.  I will try file conversion next,

Now here's a funny twist.

Yesterday via the What HiFi magazine website I found reference to a download site called 2L.  Went there and downloaded a massive 352.8khz file - and very nice it sounded too!  My V-Link clock light showed 176.4khz data stream being received.  The Naim nDAC was rock solid.  So, today I bought an album off the website, but rather than go to 352khz and pay £32 I went for the 192khz version and paid £20.  The sync light goes out.  Now I know its quite late at night but I'm finding something of a pattern here.  Multiples of 44.1khz, i.e., 88.2khz, 176.4khz and 352.8khz play fine.  While multiples of 48khz i.e. 96khz and 192khz lose the sync light.  What is that all about?