# Best Computer to DAC connection - USB, Coaxial, or Optical?



## subsonic1050

Hey everyone, I have been trying to get the most out of my computer audio, and am curious about what the best connection from the computer to the DAC would be. I have an Emotiva XDA-2 (which just crapped out on me, one day in) - and have been considering a switch to a different unit. At the same time, I am trying to determine what kind of connection I should use. With the Emotiva I was using USB - and it sounded great while it worked, but I am wondering if a different connection would be better.
  
 Thoughts?


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## subsonic1050

I would really appreciate some help with this question if anybody has any knowledge about it...


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## Ari33

I don't think there is one correct answer that applies to all kit combos, some say SPDIF sounds best... others USB but then it all depends on the kit in question.
 No guarantees, but If your DAC is asychronous 24/192 capable then you would usually use USB to take advantage of the asynchronous clock synching to reduce/remove jitter.
 SPDIF (Coaxial) is sometimes limited to 96Khz although some sources will do the 192khz.. does your soundcard support that?.
 Optical (Toslink) is limited to 96khz but has an advantage in that it is galvanically isolated which means it won't suffer from any ground loop issues that the other 2 connection types above can occasionally suffer from. 
  
 More in depth here-  http://www.head-fi.org/t/623204/digital-coaxial-vs-usb-any-sonic-differences 
  
 and here-  http://www.head-fi.org/t/588227/usb-vs-spdif-toslink-should-there-be-a-sonic-difference


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## subsonic1050

Thanks for the reply Ari - my current setup does not include a separate sound card (just the onboard sound), HE-400 headphones, and an Emotiva DAC (which I am upgrading from the XDA-2 to the DC-1). I was using the USB input on the XDA-2, but I also have a Toslink connection on my onboard soundcard. I would however, have no problem purchasing a separate sound card to run coax or Toslink through if that would provide me with better sound. 
  
 That is really the crux of the question I guess.


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## Ari33

Like the XDA2 the DC1 is also a 24/192 Asychronus DAC so (in theory at least) USB _should _be best.
 For this type of high end DAC I don't think I'd even bother with a discrete soundcard unless there were issues,... but that doesn't mean you shouldn't experiment with your PC's onboard optical/coaxial out to compare both with USB. 
  
 Enjoy..


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## subsonic1050

Awesome, that is the kind of info I was looking for. I will use USB, but will compare it to the Toslink connection just to be sure. Thanks!


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## NakkiNyan

I find the cable least important so long as it is digital.  The issue is more how many devices have to mess with it on the way to the speakers.
 All of these apply to me and are just examples...
  
 USB out:
*USB > HUB > DAC > Speaker* // I have 2 USB plugs and 5 USB devices
  
 Coax:
*USB > Converter > Coax > DAC > Speakers *// I have no coax plugs while you seem to, this is just an example
  
 Optical: 
*Optical > DAC > Speaker *


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## noahbickart

With modern DAC designs the cable type makes no difference whatsoever.
  
 It is a digital signal. It either works, in which case you hear music; or it doesn't- in which case you hear static.
  
 Use whatever you have- they'll all sound the same.


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## NakkiNyan

noahbickart said:


> With modern DAC designs the cable type makes no difference whatsoever.
> 
> It is a digital signal. It either works, in which case you hear music; or it doesn't- in which case you hear static.
> 
> Use whatever you have- they'll all sound the same.


 
 I agree, but hubs and converters kind of suck still.
  
 If you run a Mac just watch out for Optical, you lose OS volume control over optical but not USB.  The fix to add it is badly outdated.


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## brhfl

nakkinyan said:


> If you run a Mac just watch out for Optical, you lose OS volume control over optical but not USB.  The fix to add it is badly outdated.


 
 You also don't get 88.2 on (the majority of) Macs over TOSLINK. And an async USB implementation is quite likely to have better clocks.


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## NakkiNyan

brhfl said:


> You also don't get 88.2 on (the majority of) Macs over TOSLINK. And an async USB implementation is quite likely to have better clocks.


 
 Ah, I just know my last 2 did.  Actually I get 32, 44.1, 48, 88.2 and 96kHz, my latest, the Retina MacBook Pro can theoretically go up to 192kHz over TOSLINK if I use passthrough.  USB has 8, 16, 32, 48 and 96Hz.  In my case I need 48kHz for DTS which is passthrough any way.


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## Ari33

noahbickart said:


> With modern DAC designs the cable type makes no difference whatsoever.
> 
> It is a digital signal. It either works, in which case you hear music; or it doesn't- in which case you hear static.
> 
> Use whatever you have- they'll all sound the same.


 
  
 Not sure I'd agree... on a transparent system you will be able to hear differences in a lot of cases. On the same DAC a well implemented asynch USB input should be better than a well implemented SPDIF interface. Its that "well implemented" that is the important part. There are a lot of poorly implemented asych USB inputs out there that loose a lot of the benefits of "asyncness". (ie; crappy clock) There used to be a large number of dacs that just added a cheap USB to SPDIF converter in front of their existing SPDIF input, these will almost always sound worse than direct SPDIF input.

 The issue is that essentially all SPDIF inputs have some mechanism to track the data rate of the incoming data. Such a tracking system can always be bettered by a fixed frequency system. That's what async does, it uses a fixed frequency local clock, and tells the source to change the overall data rate so it matches the local clock. *If  *that fixed clock is done very well this should be better than any form of tracking. 

 Even today there are a large number of adaptive (ie non-async) USB inputs around, unless very well done these will usually be worse than a very well done SPDIF interface.


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## subsonic1050

To be clear, the asynchronous USB input on the Emotiva DC-1 should be of sufficient quality to be the best connection of the three, correct?


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## NakkiNyan

It should be at least equal to the other 2 inputs, if not better.  The thing is; can you get the signal to the DAC from a good source? if you need a hub then no, your source is worse if not completely bad so use the other options, but if you can directly connect to the computer and have shielded USB cables (I am not saying expensive, some $10 can be well shielded) then yes.


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## subsonic1050

Excellent. I don't know if my current USB cable is well shielded - any recommendations on a cable? I need at least 8' long - maybe something from monoprice?


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## NakkiNyan

I will hunt around but since most cables are measured in meters look for 3m, that is 9.8'.  I will let you know if I run across something soon, I will also put the word out to some people I know and see if I get a response.
  
 Well, I got a fast response, One of my friends recommended this one amazon.com/dp/B00062UKIY it is a $40 cable but it is on sale for about $14.
  
 I am a bit bias but I think I would choose the 10' Tripp Lite U022-010-R, you can get it on newegg for around $11 plus shipping but hunt around.  It specifies it is for "multimedia applications" and has "double-shielded cables with tinned copper braid and aluminum Mylar foil".


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## subsonic1050

I placed an order with monoprice today for some Toslink and RCA cables - threw this USB cable in there with the order since it was pretty cheap and I was already paying shipping. It is their best quality one (gold plated), but says nothing about shielding. Probably not good enough?
  
 I did look up both that Belkin cable and the one on Newegg, both appear to have a thicker "cable" section - maybe that is indicative of shielding?
  
http://www.monoprice.com/Product?c_id=103&cp_id=10303&cs_id=1030301&p_id=5439&seq=1&format=2


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## NakkiNyan

subsonic1050 said:


> It is their best quality one (gold plated), but says nothing about shielding. Probably not good enough?


 
 It likely has almost no shielding (fine for printers and other non-streaming peripherals since it can verify and resend if necessary) at that thickness and price for 10' but it is not like you can't use it for something else for less than $2 and ya, they are using gold plated as a buzz word there, the contact in the B side in the image is raw copper while the outside edge (that could be plastic) has the plating.
  


subsonic1050 said:


> I did look up both that Belkin cable and the one on Newegg, both appear to have a thicker "cable" section - maybe that is indicative of shielding?


 
It is usually a sign that it has better shielding simply because the extra foil and PVC coating takes up space.  I am already bias since I had good luck so far with Tripp Lite cables but I looked for the "double-shielded cables with tinned copper braid and aluminum Mylar foil", or similar, when hunting for a cable long enough.
  
Good luck either way and I honestly think you might be fine with the TOSLINK if you are using the DAC primarily for headphones or simple 2.0-5.1 speakers.


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## subsonic1050

Nakki - I ordered one of those Tripp Lite cables from Amazon - a seller had the 10' one on sale for $0.99! With shipping it was still less than four bucks. Certainly worth a try for that!


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## NakkiNyan

Wow, nice find. Again, Good luck and have fun with your new toys.


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## subsonic1050

In case anyone stumbles upon this thread and is curious, I have tried both USB and optical cables (my sound card does not have coax). To my ears, and with my current equipment (Emotiva DC-1 and HE-400 headphones), the quality was basically indistinguishable. I thought that _possibly _the optical cable sounded slightly clearer - but that could have been just in my head, or it could be because this Emotiva DC-1 is getting some ground noise while in USB mode. Still, if there was a difference it was so negligible as to be basically no different at all. That may change with my new heaphones and DAC/Amp.


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## NakkiNyan

A lot of what you think you hear is in your head, expectations cloud everything.  Your DAC could also be better decoding from one connection or another due to design or connection flaws, dirty USB pins or dust in the optical port for example.  The other sounds could also be in the music and the USB port has enough bandwidth to send them.  Ultimately it is hard to say which of the above happened.  Have fun with your new setup no matter which route you stick with.


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## Dimitris

Any recommendations on cable to use to connect my non USB DAC to my desktop. I have tried to use the SPDIF to SPDIF cable that I use with my squeezebox but the connection on my motherboard seems to be a mini connection. Are there any mini to SPDIF cables or should I go for TOS link one?
  
 Thank!


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## subsonic1050

Dimitirs - I don't have much of a recommendation on what TYPE to use. However, if you decide to use Toslink, I was absolutely blown away by the quality of the premium optical cables from monoprice. Their cables are generally of decent quality, but these are absolutely amazing for under $5. I would have expected to pay $50 to $70 for the cable I got.
  
http://www.monoprice.com/Product?c_id=102&cp_id=10229&cs_id=1022904&p_id=2764&seq=1&format=2


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## Dimitris

Thank you. I placed an order for one. Lets see how this plays with my DAC and amp. Cheers!


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## NakkiNyan

It sounded like your computer had the optical in the 3.5mm jack, I have these because mine is in the jack...
 full cable: http://www.amazon.com/gp/product/B0002JFN10
 converter for the old one: http://www.amazon.com/dp/B0002J2MTQ There are straight ones too but this type did what I wanted


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## Dimitris

Yep seems like these would work too!


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## painted klown

This thread has a lot of good/useful info in it. Good stuff to know for people trying to decide the best route to go. 
	

	
	
		
		

		
			




  
 I don't have anything to add, I just wanted to say that I thought this was a great thread.


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## nulk1

-Deleted-


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## DarthTater

Correct me if I'm wrong, but I think that the USB wiring is differential, so it should have good noise rejection regardless of shielding (within reason, right?)


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## astrostar59

subsonic1050 said:


> Excellent. I don't know if my current USB cable is well shielded - any recommendations on a cable? I need at least 8' long - maybe something from monoprice?





gefski said:


> Will be interested in your findings with the new dac fed via USB vs. fed via Dante.



I believe 8 feet long USBV is pushing it. I was told 5 foot is max without issues. Can't you move the PC closer?


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