It's time for some audio upgrades and i'm looking for advice on a few options i've been pondering. I currently have two systems - a mac mini (2011) and a
pc w/ asus p9x79 using the onboard realtek alc898. I connect them both to a pair of audioengine 2 speakers using 3.5mm jack. I play music on both systems (electronic, jazz, classical, occasionally rock) and do some gaming on the PC. Playing music through the mac mini sounds okay - normal for the hardware. On the PC I get an awful lot of noise/buzzing and suspect interference from the graphics card or psu. The problem seems to be more pronounced if i'm playing a game which uses DirectX.
My goals for the upgrades are:
1) resolve the sound issue with the pc
2) new pair of headphones that will work well with both the mac and pc (thinking about sennheiser hd 650's)
3) be able to use either system w/ the audioengine speakers
To resolve #1 i've ordered and received an Asus xonar essence stx thinking that it might be better shielded and higher quality than the onboard sound in the pc. After ordering the card I read a few threads in this forum that have led me to believe my purchase may not be ideal for my situation. I've seen several suggestions for using an external dac in place of the one that comes on the sound card. I have not yet opened the stx - should I return it and consider other options? Since I also want to use the hd 650's will I need a headphone amp?
Given the goals above I think I need an external dac w/ two inputs (one for each computer) and two output (one for a headphone amp, the other for the speakers). If I decide to go with the external dac is there any value to keeping the stx?
I've been considering the Schiit Bifrost dac but it appears to have only one output. The Gungnir has two but also adds $400 to the cost. Are there other options $300-500 price rangs for external dacs that have dual inputs and outputs?
For the headphone amp i'm considering the Schiit Valhalla which i've read pairs well with the hd 650's.
Thanks in advance for your advice and recommendations.