[geoges.ravel]

Does anybody know if there is a significant difference of SPDIF out between expensive sound cards and budget ones? And between USB extenal sound cards and PCI internal ones? The SPDIF out will hook with Benchmark DAC1/Bel Canto DAC2 etc.

 

[Iron_Dreamer]

Best quality would likely be from an external soundcard with an upgraded regulated power supply. From the cards which I've tested the digital output, RME > EMU > Chaintech. Of course the DAC1 doesn't care which soundcard you use, as long as it's bit-perfect, whereas other DAC's I've tried have been quite reactive.

 

[Iron_Dreamer]

D'OH, darned dial-up!

 

[geoges.ravel]

Quote:

Originally Posted by Iron_Dreamer Best quality would likely be from an external soundcard with an upgraded regulated power supply. From the cards which I've tested the digital output, RME > EMU > Chaintech. Of course the DAC1 doesn't care which soundcard you use, as long as it's bit-perfect, whereas other DAC's I've tried have been quite reactive.

Thanks Iron_Dreamer for the info. I still have a question: for bit-perfect SPDIF, should both the sound card and the DAC support it for it to work? Is bit-perfectness usually mentioned in sound card and DAC spec?

 

[stefan]

Bit-perfect means that a pure digital signal is sent out by the soundcard to the DAC. it basically refers to how the driver software for the soundcard handles the information.
With windows, if you are using "waveout" or "directsound" settings, the sound goes through a thing called Kmixer which is like a junction box for handling all PC sounds. This may or may not have a negative impact. Other soundcards automatically upsample your audio from 44.1 to 48 khz whether you like it or not.

Bit-perfect, in the PC context, basically means avoiding using driver or playback settings that avoid kmixer and automatic upsampling. Hence your data is sent straight through to the DAC without any additional messing by windows or the drivers.

In foobar there is a setting called kernal streaming. Otherwise there are soundcards that support ASIO. These are "bit perfect" alternatives to waveout and directsound.

It seems the cheapest way to get bit perfect (via optical Toslink) is the Chaintech AV710 card, cost $26. You will find guides here on how to set it up correctly.

Other than that, a search here on "bit perfect" will keep you busy looking at other models, internal and external.

DAC's will convert the signal whether it's bit-perfect or not, unless the DAC is limited to handling a 44.1 input and your card upsamples to 48. The whole bit-perfect thing is not about the DAC, its about the software side of things.

hope that makes sense.

 

[geoges.ravel]

Thanks Stepan, it's perfectly clear. So is it accurate to say that
1.no matter if the sound card is bit-perfect, the SQ is at the mercy of the SPDIF/TOSLINK cable and IO quality.
2. DACs accepting USB input perform always better in this respect.

 

[lan]

Quote:

Originally Posted by geoges.ravel 2. DACs accepting USB input perform always better in this respect.

Maybe but the final resultant sound still all depends on all the components and how you like it.

There's not a significant difference. There are many bottlenecks to appreciating the difference but when those bottlenecks are gone it's easy to hear the difference.

 

[thomaspf]

Today it is probably more acurate to say that most
DACs accepting USB input perform no better than DACs with S/PDIF input.

You can buy very expensive USB DACs that approach the DACS with S/PDIF input but for the money that these cost you can buy even better S/PDIF DACs that are pretty much immune to the quality of the digital link.

Have a look at the Benchmark DAC1 or Lavry Engineering DA10 for two designs that address jitter via reclocking and buffering.

If Jitter is a huge concern to you you can also buy a sound card that can be slaved to an external signal and look at something like the Universal Audio 2192.

Cheers

Thomas