PC onboard optical signals

[doctorjuggles]

Sorry if this is posted in the wrong place
Assuming your DAC is of a decent build and design quality, is the optical out toslink signal from a PC’s motherboard generally considered bitperfect, or is it best to output from a third-party card (mine is an Asrock Z370 Extreme4 if it matters, but it’s more of a general question for my own understanding)

 

[Blumlein 88]

The output is certainly capable of being bit perfect. The issue is usually how the OS handles things. Windows has a way of resampling or messing with audio so it may not output bit perfect signals. Using Foobar with WASAPI will take care of that as can some other playback softwares. If you have an external sound card those often use ASIO to interface with the PC and those would be bitperfect. So the answer is your optical output can be bit perfect, but you may need to jump thru a couple of hoops to make sure it is.

 

[Soniclife]

Should be perfect, as long as the OS and player are bit perfect.

 

[GrimSurfer]

From the reading I've done, TOSLINK is bit perfect. The issue, however, is that TOSLINK is a one way communications interface.

USB is two-way and, when used to connect a computer and DAC, allows the latter to take over clocking duties. This may reduce timing error because digital decoding and clocking functions within a single device can be more reliable than splitting these functions between two separate devices.

I've never done any tests to confirm this is the case. I did, however, have a few audible (!) clocking errors on my system until I switched from TOSLINK to USB 2. My server (stripped down MacBook Pro) now recognizes my DAC as THE sound card and bypasses the internal sound card/DAC entirely.

On the other hand, TOSLINK (being optical and not electrical) eliminates the risk of ground loops in set-ups prone to this kind of thing.

I guess this is an example of "dealer's choice". For me, USB makes more sense and the risk of DC noise from the computer's USB port is unlikely because my DAC is separately powered.

 

[BillG]

Assuming your DAC is of a decent build and design quality, is the optical out toslink signal from a PC’s motherboard generally considered bitperfect

TOSlink will always be bitperfect, for your intent and purpose, if:

1. WASAPI is used by the media player. Both Shared and Exclusive modes sound the same to me, but Shared has the advantage of allowing me to listen to two or more audio events simultaneously. However, I do set the media player to match the sample rate and bit depth in the Windows sound device settings, so that if any resampling is done the player performs the task. (I wouldn't concern myself about the player doing a resample, they always do for internal processing anyway, and their resamplers are of a high quality.)

2. The system and media player's volumes are set to 100%. The playback volume is then controlled by the DAC/pre/amp.

Enjoy...