[auee]

Today, I received a 1 meter optical cable by Lifatec for the Mac Mini to my Cambridge Audio DACMagic. I noticed immediately that the sound was different. I think the sound is brighter, the timing is off and possibly there is less bass impact. But I am questioning myself as I do
not have the best audio memory.

I know the cable has not been broken in, but I do not know if break in applies with optical cables. So first, is there a break in period for an optical cable? Second, with the optical output, is the sound card on the Mini affecting the sound as it would not with the USB output?

I thought that there would be a noticeable improvement by using the optical connection because of the decrease in jitter as mentioned by John Atkinson in his measurements of the jitter produced by the digital connections of the DACMagic. Perhaps, jitter is not as detrimental to sound quality as I thought and other factors are at work.

I do not think it is possible to do quick AB comparisons of the two connections as the DACMagic will not allow switching between USB and optical, only one can be connected at a time. This makes it more difficult to do a comparison, but that is what I think I will have to do.

Sorry for asking such rudimentary questions, but I am not fully up to speed on this aspect of digital and computer audio reproduction.

 

[advan031]

Is your dacmagic new as well? I have the same cable as you and I don't find the sound different at all but then again I came from straight out of the MBP to A5s.

 

[KingStyles]

Optical is the worst for jitter. Here is quote from a article about computer audio. Quote:

Toslink is the worst of the interfaces because the electrical to optical and optical to electrical conversion adds to the jitter. Toslink creates additional stages that the clock must pass through, picking up jitter due to power/ground noise and uncertainty of when the edge (logic change) transitions get detected.

Here is the link to the rest of the article.
nugent

 

[Kobra]

Quote:

Originally Posted by KingStyles /img/forum/go_quote.gif Optical is the worst for jitter. Here is quote from a article about computer audio. Here is the link to the rest of the article. nugent

Great article, thank you for the link!

 

[auee]

Ok, I switched back to USB and everything that I loved about the sound returned; the dreaded bright digital sound is now gone. I had to listen for myself and the experiment is now over. The USB connection wins hands down. Cables and connections do matter. After over 30 years in this hobby, I am still being taught that everything matters in audio. Fortunately the price of this experiment was not great; I was originally planning on spending over $100.00 for the optical cable. I am sure that the cable will be of benefit to someone who needs a well made mini plug to regular toslink cable for less than retail.

 

[Sebhelyesfarku]

I use a vdH Optocoupler cable and wasn't able to detect difference between USB and optical with my DAC. It could mean a) USB is crap on my DAC b) The vdH cable is good c) I'm half deaf. I couldn't decide which one without other references.

 

[auee]

Quote:

Originally Posted by Sebhelyesfarku /img/forum/go_quote.gif I use a vdH Optocoupler cable and wasn't able to detect difference between USB and optical with my DAC. It could mean a) USB is crap on my DAC b) The vdH cable is good c) I'm half deaf. I couldn't decide which one without other references.

I believe the problem did not lie with the cable, it is well made in all respects, but rather with the optical interface of the Mac Mini with the Cambridge Audio DACMagic. In this very specific case, the optical interface is crap and I do not think anyone should draw the conclusion that it also will be so with a different source and DAC. If you are happy with the sound of your system, then fantastic and no cause for concern.

Since there is certainly more jitter with the USB connection of the DACMagic than other DACs, as shown by John Atkinson's measurements, and I am very pleased with the sound as is, I am excited that the sound is cabable of getting even better when I move to a DAC which supports high resolution files through the USB or even firewire connection and has less jitter.

So in this respect, the experiment was a success.

 

[Sebhelyesfarku]

Quote:

Originally Posted by auee /img/forum/go_quote.gif I am excited that the sound is cabable of getting even better when I move to a DAC which supports high resolution files through the USB or even firewire connection and has less jitter.

Yeah, that's why I use optical, the USB is only 16bit/48kHz on my DAC too.

 

[Budley007]

Try S/PDIF via coax. It's suppose to be the better digital transfer between the 2 if BNC is not an option.

 

[auee]

Since the Mac Mini does not have a coaxial or BNC digital output, it has Firewire 800, optical and USB, I could go for a USB to coaxial converter for high resolution playback. But I do not think that will be my next upgrade. A quality converter for the Mac would cost more than the DACMagic costs. When I move up from the DACMagic, which I am very happy with for redbook playback from the USB port, I will probably go to either a Firewire DAC such as the Weiss Media or a more high end USB DAC such as the Ayre. I am in no rush to do this. I have not purchased hi res music and the release of my favorite music, classic rock such as Led Zeppelin in a hi res format, is not yet prevalent.

I do want to stress that I am very pleased with the USB playback from the Mac Mini to the DACMagic. Its main limitation is lack of support for hi res via USB and I am in no rush for that. I was very surprised that the optical connection of the Mac Mini to the DAC was so crappy; I had myself convinced or at least was hopeful that it was going to be better than USB. It was obviously much worse to me. However, it was a cheap lesson learned.

 

[Budley007]

You know, this is one of those situations where the guy trying to give advice ends up looking like an idiot because he didn't read the entire OP. (I didn't know you were using a Mac Mini, nor would I have know that it didn't have an S/PDIF coax out. My apologies.)

There really isn't anything you can do other than optical with the Mac Mini for S/PDIF. I've read some post on other forums concerning adapters, (Toslink>coax), but I think that defeats the purpose of what you're trying to achieve.

USB @ 16/44.1 has always been good enough for my ear. (heck...it sounds absolutely fantastic to me) If you on the other hand can hear a degradation with optical out, then I can understand your persuit for a higher resolution output. Keep us posted.

 

[auee]

Quote:

Originally Posted by Budley007 /img/forum/go_quote.gif You know, this is one of those situations where the guy trying to give advice ends up looking like an idiot because he didn't read the entire OP. (I didn't know you were using a Mac Mini, nor would I have know that it didn't have an S/PDIF coax out. My apologies.) There really isn't anything you can do other than optical with the Mac Mini for S/PDIF. I've read some post on other forums concerning adapters, (Toslink>coax), but I think that defeats the purpose of what you're trying to achieve. USB @ 16/44.1 has always been good enough for my ear. (heck...it sounds absolutely fantastic to me) If you on the other hand can hear a degradation with optical out, then I can understand your persuit for a higher resolution output. Keep us posted.

Thank you for the kind remarks and I was not offended by your post in the slightest. I agree that redbook can produce excellent music. However, I have heard high res music and it is superior. But not so much so, that I am willing to break the bank to get it. I will be very excited when some of my favorite classic rock albums are released in high res if such files actually improve the sound substantially.

 

[Budley007]

Yes, I've heard some higher resolution samples and agree with you, wholeheartedly. If and when redbook is surpassed as the standard, I'll be in the same dilemma you're facing now. FWIW, I have heard some great things mentioned about the Apogee Duet. If you ever decide to sell the DACmagic and go from there, you might want to give it an audition. Apogee makes great products.

BTW - I knew you weren't offended. Your response, if anything, expressed more patience than I deserve.