DAC/AMP for HD 558 - confirmation bias?

Hey,

I recently purchased the Sennheiser HD 558 for (mostly) gaming, now I'm looking to find the best possible setup for these headphones. I was able to lend a DAC from a colleague for testing purposes. It connects through a S/PDIF toslink cable.

It seemed (!) to do a better trick of making the audio more clear and somehow it even seemed to give me better positional audio aswell (in BF4 and CODBLOPS2. However I'd like to know what might be the suggestion for the best possible sound setup in my scenario. Also I want to be sure I'm not purchasing something because of a confirmation bias.

My motherboard is the X99S Gaming 7 with the Realtek AC1150 Codec onboard. I've been doing quite some research on DACs and sound cards but there's this saying about a forest and trees or something... :)

It basically boils down to this: Will I benefit from using this DAC over connecting my headphones through the 3.5mm jack on my motherboard in terms of positional audio and sound quality or not?

Thanks for the help!

Edit: The headphones have an impedance of 50 ohm.

Your motherboard may cut it if you like it, but most likely the DAC/Amp combo will help a little. From my own experience with the HD 598s, a DAC/Amp significantly improved the sound out of them, they were slightly muddy and congested on my onboard, but on a FiiO E10K, it really opened up and tightened up.

Again, this is subjective, if you like it, you like it. No one can tell you otherwise.

As far as positional audio goes... maybe a little? Just by virtue of delivering cleaner more accurate audio to your cans. As for whether or not it's worth it to you, that's your call. Adding an amp into the equation with the DAC would probably help quite a bit though, even on low impedance Sennheisers. Like VXAce, I have the HD598, and they REALLY benefit from being amped. The 558 would likely as well, if somewhat less so (30 ohms vs 50 ohms on the 598).

But, it's up to you. If you're fine with the sound you have now, then there's no need to change. If not, then by all means.