[sdelange99]

Hi all,
 
I've recently set up my first 'real' audio system with a Yamaha A-S201 amplifier, Sennheiser HD 650 headphones and a pair of old (but still quite good) Mission 760 speakers. Because I received my HD 650 a few weeks after the rest, I used the speakers and was quite happy about the setup. I knew my laptop soundcard wasn't all that great so I went looking for a DAC.
 
While I was looking for a DAC I also received my HD 650 and directly returned the amplifier because of the relatively high noise floor on the headphone output. I switched to an Onkyo A-9010 which has no really noticeable noise. My quest for a DAC stopped as the Onkyo has digital inputs, so I could save a few bucks by going the digital way.
 
My question is: is there any difference in sound quality between USB sound cards with a digital output (assuming they support the same sampling rates and bit depth)? At first I thought not, as the sound stays digital from the USB port to the amplifier. But as I'm not 100% sure, I thought it's a good idea to ask more experienced head-fi'ers.
 
Kind regards,
 
Sander

 

[sdelange99]

bump

 

[PleasantSounds]

The only difference I can think of is jitter or signal timing errors. The card with more precise clock may give you a slightly better result. Jitter has been often demonised by implementers of expensive precise clocks, but in terms of real life experience the difference between excellent and average is usually hard to detect.
With some DACs however it matters even less, as they do internal buffering and reclocking if signal. Not sure though if your Onkyo would fall into this category (most likely not).

 

[DDF]

A transformer coupled usb output made a significant obvious improvement in sq in my system. Its breaks the ground path from the noisy nasty pc switching supply and the dac. This wasnt tweako, but obvious

 

[NiHaoMike]

The headphone outputs on many (if not most) modern digital speaker amplifiers are more or less afterthoughts. They often use a cheap DAC chip (also used for auxiliary analog outputs) as it's cheaper than using a relay to switch the output. (How many "ordinary" users actually use the headphone jack on those things?)
 
As for the quality of the fiber, the better stuff will send the signal further and be more robust.