What is the best digital input on a DAC?

[admin_exported]

I would like to canvas opinion on the merits of SP/DIF, Optical and USB digital inputs on DACS.

What are the technical advantages of one over another and the quality of sound via each?

 

[John Duncan]

For 16/44, USB and Electrical should be the same. Some DACs' USB inputs are limited to 16/44 so can't play higher res content. Optical is in theory inferior to electrical since there's a conversion process that needs to take place which risks the introduction of jitter.

All that said, I use optical from my apple TV to my DACMagic, and it sounds bloody marvellous.

 

[idc]

It seems to me that if there really was a sound difference between optical,digital and USB, it would have been well and truely noticed by now, especially since so many DACs can handle all three formats.

 

[Gerrardasnails]

idc:
It seems to me that if there really was a sound difference between optical,digital and USB, it would have been well and truely noticed by now, especially since so many DACs can handle all three formats.

I think if you can use coaxial, go with that as at the very worse, it will sound as good as optical or USB. If you only have optical or USB, I wouldn't worry a jot. Saying that, I have noticed a difference in standard coaxial and very good cables. You tend not to get as many options/fancy expensive cables with optical and USB as you do with coaxial - another example maybe that coaxial is the premium option.

 

[idc]

Fair point Gerrardasnails, but USB is not one thing with 1.0, 2.0, 2.0 high speed and now 3.0, each allowing higher bit rate transfers.

 

[Thaiman]

I think ther are there for options depending on your transports output terminals rather than sound quality.

 

[chebby]

Most DACs only need to operate at USB 1.1

That is plenty fast enough - at up to 12Mbps - for 16bit/44.1khz iTunes lossless. (An example is a lossless track I recorded the other which plays at 1.4 Mbps) I assume it is fast enough for the other 16/44 lossless formats. (DACs that can operate 24/96 on USB presumably use USB 2.0)

When I got the Beresford it was because I needed optical from my DVD/HDD/Freeview recorder and USB for my laptop.

However, I took the opportunity to compare both USB and optical (from an iMac 20" using AIFF tracks ripped losslessly from an excellent MSFL Gold CD of Roy Orbison's greatest hits specially for the test). It cost me £4.99 for a Toslink mini jack adaptor from the local Sony shop!

Anyway, the upshot of my test was that there was no perceptible difference (to me).

Good job really, as I never intended to use my iMac or optical for this purpose. (I had to bring the iMac in from another room where it normally lives.) I just wanted to know.

Some adherents of a certain American valve DAC company swear by the superiority of USB.

I just enjoy having the convenience of both and the knowledge that (to my ears) both USB and optical sound as good.