TOSLINK vs. USB
Dec 25, 2013 at 12:19 AM Thread Starter Post #1 of 14
jeremy205100

jeremy205100

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So I recently purchased the TEAC UD-H01 DAC and headphone amplifier. I have used both the optical input (with the headphone jack digital out on my MacBook Pro) and the USB input. The USB sounds significantly better. Does anyone know why this is? 
 
Also, I've been uplugging a lot of optical cables lately and I was wondering if the laser on the cable can blind. I haven't gotten it in my eye or anything but it would be nice to know how careful I should be.
 
Dec 25, 2013 at 5:45 AM Post #2 of 14
Hi, merry Christmas!
 
I think this topic has been discussed before, so you could find a better answer than mine searching in the forum.
 
For me, USB asynchronous is much better than toslink. I have a Mac Mini and the sound I get from the USB is superior than the sound I get from the optical connection. I also think coaxial is superior than toslink.
 
The advantage that toslink has is electrical insulation from the computer/source, but it can be addressed with an adequate digital-digital converter.
 
Toslink sounds good from my CD player connected to my dac than from the computer, and my CD player does not have coaxial, so I have to live with it anyway.
 
Best Regards,
 
Daniel
 
Dec 25, 2013 at 1:21 PM Post #3 of 14
If I mght chime in here:

I also plan to use a Macbook Pro as a player with my DAC where the music is stored on a "portable RAID array" consisting of 2x2TB discs taped together with a USB hub.

I read recently that the quality of the USB connection might suffer if there are several USB devices connected. (I will have the hub connected on one of the two sockets, the DAC will be connected on the second)
Does anybody have some experience with this?

My DAC (Metrum Acoustics HEX) does not use the USB power coming from the Mac. Might this just be an issue with USB powered DACs?

thanks for any input!

merry Christmas from Norway!

Dave
 
Dec 25, 2013 at 2:13 PM Post #4 of 14
You might have issues, especially if storage is connected to the hub. The hub only has a certain amount of data throughput, and if too much is being used by other sources then the DAC won't receive the maximum audio throughput that it should. You could remedy this by connecting the DAC to a built in USB port on the computer rather than the hub. 
 
Does anyone have any answers to my questions though?
 
Dec 25, 2013 at 3:16 PM Post #5 of 14
thanks for your reply!

I might have been unclear: the hub goes in one built-in USB port of the Macbook, the DAC in the other built-in port.

Can't give you a definitive answer there, but I read in a few places that the optical out of a Mac is not the best one. Which optical cable are you using? While the cables themselves are usually quite good, the connectors on some aren't. You might have a serious jitter issue here...

Maybe the implementation of the USB-in on your DAC is just that much better :):
 
Dec 27, 2013 at 3:56 AM Post #8 of 14
jeremy205100 said:
  So I recently purchased the TEAC UD-H01 DAC and headphone amplifier. I have used both the optical input (with the headphone jack digital out on my MacBook Pro) and the USB input. The USB sounds significantly better. Does anyone know why this is? 
 
Also, I've been uplugging a lot of optical cables lately and I was wondering if the laser on the cable can blind. I haven't gotten it in my eye or anything but it would be nice to know how careful I should be.
Click to expand...

 
It's hard to say if what you've been hearing exists for sure. Conduct a blind test, that'll confirm your observation.
 
Jan 3, 2014 at 4:12 AM Post #9 of 14
Asynchronous USB is a timed, controlled transmission of analogue audio data. Should packets be dropped, the receiver asks the host to send them again.
 
Toslink has no timing marks, and is just data (an analog voltage), with no error correction or a timing master, same as COAX, or AES/EBU. The electrical to optical interfaces can affect the timing of data, hence can and do introduce jitter, which is heard as smearing.
 
If you are after electrical isolation, Icron Ranger produce a media converter suitable for USB 2 Audio which can transmit, DSD2x if you wish over FO without timing errors.
 
Jan 3, 2014 at 6:08 PM Post #12 of 14
a_man_eating_duck said:
   
Gotta be a typo there. .....controlled transmission of digital audio data..... Nothing is analogue until the DAC does it's thing.
Click to expand...

It's a deliberate description. All circuits in a computer rely on the transmission of voltages whether they be full logic high or lows, a data stream or crap transmitted with the signal. These signals can be measured with a multimeter if you are game, or more appropriate a logic analyser. As far as I know, there's difficulty with the term 'digital voltage', doesn't make any sense.
 
Voltages can be pure DC, a flat line, or alternating voltages from the mains or power line, or weird square waves as we find in computers. Because they vary above zero, they are all analogue in nature, not really digital, how do you define a digital voltage....? The waveform, shape, timing pulses....pretty much open ended. The transmission of voltages also explains why and how noise gets transmitted from the computer to a DAC, the noise is coupled with the signal, the shield, the 0V, and a combination of all three, as an analogue voltage.  
 
Since there is no such thing as digital voltage, then the description of analogue voltages are apt. 
 
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