Usb vs Optical
Feb 12, 2013 at 10:30 AM Post #16 of 46
Some times that same onboard audio could have glitches which makes even using the optical out a pain.  My VIA audio chip gave me so much pain, trying to use it optical out. That I got a cheap used sound card for optical. I don't use the USB of my NFB-12 only because I do alot of PC gaming,and it cause game audio issues, Could be because the usb in the NFB-12 is sync instead of Async. If all I did was listen to music and watch movies  and not game, then it be a different story,But I do all 3.
 
Feb 12, 2013 at 5:35 PM Post #17 of 46
All I can say is that USB is one of the easiest ways to reduce jitter as you can tell which clock to be the master and which to be slave.  It would be very difficult to tell the difference between a high dollar transport and the USB 2.0 fed m903 DAC.
 
Feb 18, 2013 at 5:36 AM Post #19 of 46
I don't think USB is inferior to Toslink connection. Their are three different USB implementations: adaptive mode, asynchronous mode, and bulk mode. The adaptive mode is not fully suitable for audio since the DAC will be slave to the computer thus jitter becomes a big issue. In the other two modes, computer is a slave to the DAC which controls the timing of signal transmission between computer and the DAC. As a result we can have good sound quality. In addition, measurements have shown that a good USB interface can provide the lowest jitter measurement.

On the other hand, jitter is not always a bad thing. Sometimes jitter can make your music sound better to your ear. That's why some USB to S/PDIF converters are favorable to some people even though it introduces more jitter into the chain.
 
Feb 18, 2013 at 6:08 AM Post #20 of 46
Quote:
On the other hand, jitter is not always a bad thing. Sometimes jitter can make your music sound better to your ear. That's why some USB to S/PDIF converters are favorable to some people even though it introduces more jitter into the chain.

Add to that the fact that a USB to SPDIF converter has even worse  issues than adaptive USB. The data timing between the adapter and the DAC it is plugged into is not controlled by the adapter or the DAC.
 
Feb 18, 2013 at 6:16 AM Post #21 of 46
Add to that the fact that a USB to SPDIF converter has even worse  issues than adaptive USB. The data timing between the adapter and the DAC it is plugged into is not controlled by the adapter or the DAC.


I totally agree with you on this. That's why IMO it is best to avoid introducing converter to the chain. High quality USB to S/PDIF is expensive (OffRam, ...). Just save that money and add a little more then one can buy high quality DAC with well implemented USB connection
 
Feb 18, 2013 at 12:11 PM Post #22 of 46
i've never used optical.
But have used USB and Digital S/PDIFcoax whatever its called.
I sort of think the Digital sounds better... but, it is in no way scientific, and my dac will playback  96 and 192 with digital but not with usb.   i've never thought the upconverting makes a big difference.
 
how does the optical compare to the digital coax as far as connections go?
 
Feb 18, 2013 at 3:23 PM Post #23 of 46
Quote:
i've never used optical.
But have used USB and Digital S/PDIFcoax whatever its called.
I sort of think the Digital sounds better... but, it is in no way scientific, and my dac will playback  96 and 192 with digital but not with usb.   i've never thought the upconverting makes a big difference.
 
how does the optical compare to the digital coax as far as connections go?

 
Coax and optical S/PDIF should deliver exactly the same bitstream if everything's working properly. The real difference is an optical interface can provide additional isolation from EMI and RFI. Of course, whether the two interfaces do perform identically is not guaranteed. If one or the others is poorly implemented, it will suffer.
 
(Note: S/PDIF and USB are both digital interfaces.)
 
Feb 18, 2013 at 7:18 PM Post #24 of 46
I've gone through a lot of gear of all levels and if there is not appreciable noise in the background from whatever source you're using, I hear essentially no difference between any digital source/ connections- USB, coax or optical.
 
Feb 18, 2013 at 7:53 PM Post #25 of 46
Tos is bandwidth limited and and the trancievers have a good deal of jitter compared to coax when both are optomized. It's been that way forever and it's easy to 'float' coax as well. USB interfaces are finally getting up to speed and preferred for PC use with proper implementation but I still don't think a PC is the best platform to test source connections. I use a firewire JetPLL/Dice II to Coax interface when I need to use a PC. http://www.tcelectronic.com/media/1018472/frandsen_travis_2006_clean_clocks_tc_1_.pdf
 
Feb 21, 2013 at 2:19 AM Post #26 of 46
Ok guys, thanks for all the input.  After a long delay I finally tested my Bifrost/Asgard combo with my new optical cable.  Now I will put a short little review on the comparison and my thoughts, but let me explain a few things first..
 
My setup has been PC -> AudioQuest USB -> Bifrost -> Asgard
 
Ok so what I did was listen to about 3 different songs, let my ears rest for a second then plugged in the test setup..
 
Test setup:  PC -> Optical Cable -> Bifrost -> Asgard
 
I used only one pair of headphones for both of these and the pair i chose to use were the Sennheiser HD 650's.
 
Now, its really hard for me to tell a difference between sound unless I can listen to something, then listen to something else playing the same song IMMEDIATELY after. (and in this case it is impossible for such a test, because I only have one Asgard, and one Bifrost.)
 
Let me assure everyone that I am the type of person that does not make things up, I don't pretend to hear differences when I do not hear any difference.  I am completely real on my opinions and needless to say, sometimes I don't get along with other audio enthusiasts with their head in the clouds.  I'm very down to earth and only believe things when I hear them or see them.  I don't make things up and that is one of my pet peeves about this "hobby".  False claims make me very mad, and I also sometimes hate the fact that everyone's hearing is different, because that just adds on another layer of challenge when reading and understanding someone's thought process when it comes to audio.
 
With that out of the way let me explain a few facts about the 2 different setups.
 
My usb setup has served me well, the Bifrost makes a great soundcard for my computer.  The one major complaint I have with my usb setup is that at higher volumes (once you start surpassing 50% volume) their would be jitter and it would sound like interference.. it wouldn't be extremely loud or anything, and for the most part you could only tell if nothing was playing, but it was there, and knowing its there with no music, is unsettling, because it probably is in the background WITH music, its just hard to notice.  Something that would really make it louder and with even more distortion is when I would move the mouse, or click the mouse.  I have tried incorporating a powered hub and the problem is still there.
When i swapped to optical, as you could guess (being highly resistant to electric interference and distortion) the optical cable completely removed this issue.
 
Now those are the facts, the following are things that aren't necessarily something I would call fact, because I feel it could be my head playing games with me.  Like I said, i am not comfortable completely, unless I have 2 exact setups and can switch between them to tell the difference immediately.  Anyway here are things that are possible..
 
Now, switching to optical and turning on a song I had been playing through usb made me think ok, this sounds a little clear, like there was a little smoke on the songs with USB, and it was always in the back of my head that there could possible be electric interference going on, and even sometimes I would hear a crack or pop in a song, but I would always pass it off as just part of the song so I never really kept tabs on which songs those were so it was impossible for me to test that, but let me say that with optical - there was no popping or glitching in any song that I played.  The next impression I got was that drums sounded better, this happened on 2 of the 3 songs I listened to.  The drums just seemed to sound better with optical, especially the snare.  Now this is probably all in my head, and I hate the fact that I do not know for sure, but that is why i put a disclaimer. 
 
Either way the facts remain, if anyone has any suggestions on how to clear up interference via usb, I would love to hear it, because the thought of using my onboard soundcard in anyway is really annoying to me, I dont know why, but it is.  In the meantime I'm still going to be using usb just because of that fact, but if i can't find a fix for the interference at higher volumes, I will permanently switch to optical. 
 
To sum everything up, I honestly feel that if i just found a way to clear up any emi, or popping, in the usb.. then the sounds between the two cables would basically be the exact same.  And thats my real opinion.
 
(Also don't let me fool you into thinking the emi from the usb is completely noticeable all the time or anything, its just something that happens sometimes and ALL the time at really really high volume.  Otherwise usb is pretty great, all things considered.)
 
Thanks for reading, please comment!
 
Feb 21, 2013 at 8:15 AM Post #28 of 46
Quote:
 
Thanks for reading, please comment!

 
Expensive "audiophile" USB cables are a scam, but that doesn't mean that there can't be differences between cables - eg a cable could be broken. (It's a fallacy to think that a USB cable will work perfectly or not at all with audio, for reasons that would be moderately complex to explain.) I'd try any spare ones you have lying around, making sure that you try ones with and without those cylinders on the cable that are supposed to fix em noise. (These can fix some problems but can create others.)
 
And if you can get some one to work the gear in a blind test for you, that's even better.
 
Feb 21, 2013 at 11:51 AM Post #29 of 46
You really haven't told us enough about your setup. What OS, player, asio, Wasapi, Kernal? Are you using this driver for the BiFrost? http://schiit.com/downloads/U6631_U6631A-1.01.zip Lots to get right before you can get a solid result and that noise you're hearing is not jitter. It's noise that you need to solve. besides the driver and USB cable, I'd also check for a ground loop since the Bifrost is AC powered.
 
Feb 21, 2013 at 12:22 PM Post #30 of 46
Quote:
You really haven't told us enough about your setup. What OS, player, asio, Wasapi, Kernal? Are you using this driver for the BiFrost? http://schiit.com/downloads/U6631_U6631A-1.01.zip Lots to get right before you can get a solid result and that noise you're hearing is not jitter. It's noise that you need to solve. besides the driver and USB cable, I'd also check for a ground loop since the Bifrost is AC powered.

+1 
 
It might be a latency issue that you are encountering with your PC that is causing some form of audio dropouts,pops or clicks.
Try this http://www.thesycon.de/eng/latency_check.shtml to check if your PC can handle real-time data streams properly, although solving the lantency issue is another headache altogether cause some systems are just bad at handling latency.You can try the suggestion on the site if latency is your issue here.
 

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