Audiolab MDAC Problem ? . . Clicking noise when listening to iTunes via Audiolab MDAC ?

[admin_exported]

Hi from a new member who just joined the forum today.

I have a problem with sound quality of my Macbook/Audiolab MDAC set up and wondered if anyone has encountered a similar problem and can offer any advice ?

My set-up comprises a Macbook Pro (core i7 2.5 Ghz / Lion 10.7.5) running iTunes 11, all my music is encoded in Apple’s hi quality lossless format. I’m using a USB output on the laptop to supply the USB input on the Audiolab MDAC, and the MDAC then feeds into my Musical Fidelity A5 pre-power amp system, so it’s a straight forward set up.

My problem is that there is a continual background “ticking” or “clicking” type sound when I listen to my iTunes music. It’s a sort of random background click about every 5 to 10 seconds but not consistent in time period. (Ironically, it sort of sounds just like the “click” you get when you play a scratched vinyl record !) If I listen to the same source songs using my headphones via the macbook headphone output the songs sound fine, and there is no clicking, so I’m thinking there is nothing wrong with the quality of the actual iTunes library.

I also experimented with plugging a friend’s dell laptop in as the source. His iTunes library is saved at the lower 192 sample rate and his stuff sounded fine through my MDAC. No clicks, just playes fine.

So I think I’ve narrowed it down to either a problem in my Macbook Pro sending the data to the Audiolab MDAC or a problem with the MDAC not being able to handle the lossless rather than 192 data stream . . . . ? ?

Any thoughts, suggestions or advice would be greatly welcomed/appreciated ?

 

[quadpatch]

This is an odd problem. could it be that you have another USB port in use? I get issue with all of my DACs when I transfer data to a USB flash drive. The M-DAC is the only device that has told me that there is something wrong. It flashes up on the screen that it's flushing the buffer, but it sounds horrible and seems worse than what you're experiencing.

Doesn't your Mac have an optical out, can you try that with the M-DAC just to narrow the issue down a little further?

I assume that you are using bit-perfect on iTunes. The PC version doesn't support it any more I think but for Mac I'm sure it still does. Again, I'm just curious to narrow things down, I'm not quite sure what the problem might be.

NOTE: It's probably not that relevant but - I'm assuming 192 is the 'Bit Rate' of your friend's music (probably mp3 - usually up tp 320kbps), rather than 'Sample Rate'. Lossless is usually above 500kbps for CD quality. 'Sample Rate' is measured in Khz (eg: 44.1, 48, 88, 96, 192 etc.)

 

[eggontoast]

Which firmware are you running on your m-dac, I seem to remember there being an issue with the USB driver on one of the OS for macs. John Westlake (or Dominik) did a change in V0.8A I think it was to get it working properly.

 

[Anonymous]

Hi there,

Many thanks to quadpatch and eggontoast for your input.

To clarify my original post and answer your questions;

I don’t think my macbook pro has an optical output – so I haven’t been able to try that. As far as I’m aware Macbook Pro’s don’t have optical outputs ?

I don’t think I’m using ‘bit-perfect’ on iTunes, but that said, I’ve never heard of it and don’t know what it is or how it might help ? . . .

Yes, apologies, 192 was indeed the bit-rate of my friends MP3 based iTunes library, whilst my iTunes library is as I stated Apples Lossless Encoder (and for info I’ve got the error correction box ticked on my import settings).

Finally, an update on my symptoms, this afternoon a friend brought round an Alan Parsons Test CD which I’ve added to my Library. This disc has lots of different reference tone tracks and thus enables me to listen to the click artefact I’m hearing against the background of a consistent reference noise rather than music. Interestingly this revealed that actually the click noise is regular and about every second rather than irregular as I’d previously described it (I think the clicking was being masked a bit when I was listening to the clicking noise through rock music). And, more interestingly still, I’ve now also discovered that the pitch of the clicking noise appears to change with the pitch of the noise being played . . ie, if I play a 250Hz reference sound track, the click itself sounds deep or low, whilst if I’m playing a 1kHz reference tone track then the clicking noise sounds much higher ?

Oh finally, I’m not sure what firmware is on my MDAC, and I don’t know how to find out ?

Thanks again for your help any more advice very much appreciated ?

 

[eggontoast]

Press the volume knob while powering up to check the firmware version (just turn off to exit this mode)

Have a look on the official wiki page, all the latest versions of firmware are there along with instructions on how to load them

 

[Anonymous]

Hi,

My Audiolab MDAC Software revision reads v0.99 / v0.97

Thanks

 

[woodster]

I take it you are using a USB2 lead, not a 1.

Check your power supply lead is pushed fully home, I intially experienced a clicking with my Audiolab 8200cd, due to my being over weak pushing in the power cable...doh.

 

[eggontoast]

Hi,

My Audiolab MDAC Software revision reads v0.99 / v0.97

Thanks

Update it with the latest version from the wiki page and retry, you will also get a little extra functionality as a bonus.

 

[chebby]

Hi there,

Many thanks to quadpatch and eggontoast for your input.

To clarify my original post and answer your questions;

I don’t think my macbook pro has an optical output – so I haven’t been able to try that. As far as I’m aware Macbook Pro’s don’t have optical outputs ?

The 3.5mm headphone minijack usually doubles as a Mini-Toslink optical connection. (Just need a £5 adaptor)

 

[Anonymous]

Thanks for all the information which is very helpful.

My USB cable is a USB2 and is firmly pushed home, I've also tried a different USB cable but that didn't make any difference to my problem.

Looks like my MDAC software/firmware is out of date, so I was thinking about updating . . . do I need to download and install each sucessive update until I've got them all (there are many sucessive updates listed on the wiki page) or can I just go from my very early version straight to downloading the newest firmware and get up to date with one download ?

Also, is it better to download the software from the Wiki audiolab page (which shows a whole history of different downloadable files) or just go to the audiolab site, where there is only one ZIP file to download ? . . . though there are no instructions on the Audiolab site on how to do the update procedure . . for example I dont even know how to download and run a zip file on a macbook ? .

Thanks all for your help

 

[Anonymous]

Well,

Just downloaded and installed the latest software update from the Audiolab Wiki page.

First impressions are that it seems to have cured my clicking proiblem.

So . . . . . very big thanks to all who have advised me with this problem,

Cheers and merry christmas from the wet and windy Mendip hills !

 

[eggontoast]

Glad to have helped, it seems you have answered all your own questions from the previous post but just incase, you can roll back and forth between the firmware versions at your leisure.

 

[sumi26]

Hi All,

I have upgraded the firmware and the problem still there with Mac latest OS in MacBook Pro. I tried with another source - windows 7 (foobar2000) and there is no issue. Anyway to contact Audiolab support developer?

 

[shadders]

Hi,

Does the music interrupt when the click occurs or is it over the top of the music ?.

Thanks and regards,

Shadders.

 

[sumi26]

It is on top of the music. soft clicking sound constantly whenever i played the music. it disappear when i stopped the music. any idea what is the possible issue?

 

[shadders]

Hi,

This sounds like a driver issue - initally i thought it may be the cable - but it is apparent only when you play music, and does not occur on other platforms - so it does sound like a driver issue.

Do you know the chipset in the DAC for USB ?.

Have you tried a different USB cable ?

Does the Mac have optical output - have you tried that at all ?

Apologies - i do not know specifically, what the issue is.

Regards,

Shadders.