Head-Fi.org › Forums › Equipment Forums › Cables, Power, Tweaks, Speakers, Accessories (DBT-Free Forum) › Optical TOSLINK vs. USB: Which connection is better to connect a DAC?
New Posts  All Forums:Forum Nav:

Optical TOSLINK vs. USB: Which connection is better to connect a DAC? - Page 2

post #16 of 105
Quote:
Originally Posted by myinitialsaredac View Post





The issue I would argue still lies in using the computer clock. In that thread they specify that the chip if the jitter input is low will correct for theoretically all of it, however if it is high it will still cause phase modulation. 

 

I think the theoretical ideal would to be using error-correction transfer into a buffer and clock it out on the DAC side.


I actually contacted Bruno Putzeys a few years back. He didn't provide me with his detailled measurements for the SRC4192 but said that the jitter had to be at least in the "tens of ns" for the chip to revert to classical PLL operation. Gordon Rankin measured a PCM2706 at 3400ps (3.4ns).
post #17 of 105
Quote:
Originally Posted by 00940 View Post



I actually contacted Bruno Putzeys a few years back. He didn't provide me with his detailled measurements for the SRC4192 but said that the jitter had to be at least in the "tens of ns" for the chip to revert to classical PLL operation. Gordon Rankin measured a PCM2706 at 3400ps (3.4ns).


Interesting  ph34r.gif

 

Dave

post #18 of 105
Quote:
Originally Posted by vert View Post

Quote:

I think the theoretical ideal would to be using error-correction transfer into a buffer and clock it out on the DAC side.

Matter of time eh?

 

I believe the Chord QBD76 already does this. Doesn't matter though, I still get a different sound from USB, toslink, and Halide Bridge. The best sound sound is via Halide Bridge, but I'm sure if I spent beaucoup bucks on a USB cable, or connected the toslink to a nice sound card instead of my Macbook's digital output, I'd get much better results that might comparable to the Halide.

 

What I'm trying to say is even with the most sophisticated jitter rejection technology DACs, the sound is still sensitive to high jitter.


You are correct that the chord drops it into a RAM buffer, I wonder if it allows for two way comm over usb for error correction. If it does this and you experience difference in sound between halide and optical it means that:

optical is flawed compared to the usb as the usb would be considered "perfect"

Halide bridge introduces error

 

If it is not two way comm over usb with error correction then it means there are differences between the three inputs in terms of bit correctness and possibly jitter. 

 

Intriguing. 

 

Dave

post #19 of 105
Can't sleep so I found this : http://www.stereophile.com/content/music-hall-dac252-da-processor-measurements For this DAC using the SRC4192, jitter is vanishing for both SPDIF and USB as it should... Which tends to point where a not so good implementation of the SRC4392 as SPDIF receiver.

At the point, I probably lost the OP... sorry for the OT.
post #20 of 105

imo go coax or toshlink

 

Try both, I pick up a little noise on usb on a few systems and its not really any easier to work with.

 

I think the "audio chips" behind coax and toshlink are a lot more mature than usb and its fair to say you can always get a good optical connection, but its possible a USB implementation (especially pre win7) might be slightly flawed.  Newer DACs and systems should have no issues...ive tried about 15-20.

 

On my main rig and laptop I cannot tell the difference between the 3, so I use coax on the desktop and toshlink on the laptop.

 

I am not a cable believer and I am not a good enough listener to hear jitter...so the math guys like to argue but I can NOT tell unless I am picking up noise.

 

I have more trouble with tubes picking up room noise than USB anyways...

 

Currently listening to my MHDT Havana -> speaker rig over coax from a win7 custom SSD based build...

post #21 of 105

There should be no difference between USB and Optical because they are just sending a digital signal and not analog.  It's the same principal as HDMI cables.  A $3 hdmi cable is just as good or better than some $100 monster cable when it comes to digital signals.  The DAC turns 1's and 0's (digital data) into actual sound and it shouldn't get any interference of any sort because of this.  Perhaps being electrically connected through a USB cable could produce some noise, but I doubt it because the DAC is only looking for data and not any interfering signals.  

post #22 of 105
Quote:
Originally Posted by VulgarDisplay View Post

There should be no difference between USB and Optical because they are just sending a digital signal and not analog.  It's the same principal as HDMI cables.  A $3 hdmi cable is just as good or better than some $100 monster cable when it comes to digital signals.  The DAC turns 1's and 0's (digital data) into actual sound and it shouldn't get any interference of any sort because of this.  Perhaps being electrically connected through a USB cable could produce some noise, but I doubt it because the DAC is only looking for data and not any interfering signals.  


IMHO, It actally does matter, and it's not as simple as sending 1's and 0's because that is not all that there is.  Each cable has a completely different way to implement the signal, and it is nothing like computer networking.  Coax generally is best, followed by optical followed by USB.  Optical is divided by plastic and glass media where plastic is generally inferior to glass.  Also, the cable carries signals which get translated to those 1's and 0's and there are differences between cables too.

 


 

post #23 of 105

Quote:

Originally Posted by mikemalter View Post
IMHO, It actally does matter, and it's not as simple as sending 1's and 0's because that is not all that there is.


For better or worse, in the real world, every little change makes a difference. Even with manufacturers who claim that their DAC rejects jitter to a negligible amount, you can easily test this by plugging in a toslink connection from a computer versus a high quality USB to spdif converter. The difference is quite large.

post #24 of 105
Quote:
Originally Posted by vert View Post

Quote:

Originally Posted by mikemalter View Post
IMHO, It actally does matter, and it's not as simple as sending 1's and 0's because that is not all that there is.


For better or worse, in the real world, every little change makes a difference. Even with manufacturers who claim that their DAC rejects jitter to a negligible amount, you can easily test this by plugging in a toslink connection from a computer versus a high quality USB to spdif converter. The difference is quite large.


'Zactly.
 

post #25 of 105
Quote:
Originally Posted by UncleSkeebow View Post

I prefer the sound of USB, (denser, warmer and more present) but if you have a noisy computer system, (interference) optical will isolate that noise and may in some cases give you better sound.



You are taking the p*** aren't you? I can't detect sarcasm when it's typed.

post #26 of 105

USB is universal, doesn't really change from system to system.  Toslink is ruled by implementation on PC end, and DAC end.  Different receivers, jitter rejection, ect ect ect.

 

Whether the difference is audible its up to you.  I personally prefer good ol RCA/BNC(Spdif COAX) for audio, less in the signal path.

 

Optical is more reliable over distance runs though~

 

USB is the least reliable of the two since it is essentially a data cable rather than sending to a rather limited device(such as a dac).

 

End of the day though.... if its audible to you stick with what you need.  If not go with what is that more elegant solution.

post #27 of 105

Digital always sounds cleaner to me. With usb I somtimes get colloration or interference. Also, usb sounds really bad after 30ft or so.

post #28 of 105

USB is digital, just FYI. ;)

 

I think it very much depends on the DAC and implementation of the digital input.  With some I've noticed no different, but with others quite a bit where they were even sensitive to optical cables.

post #29 of 105
What about if the usb dac is mains powered, then the only signal the dac will want for the usb is the sound then how does that compare to optical,coax?.
post #30 of 105

I agree that there are pros and cons to USB and toslink-spdif when compared against each other. But coaxial-spdif is superior to both.

New Posts  All Forums:Forum Nav:
Head-Fi.org › Forums › Equipment Forums › Cables, Power, Tweaks, Speakers, Accessories (DBT-Free Forum) › Optical TOSLINK vs. USB: Which connection is better to connect a DAC?