The optical out on your motherboard to the enog2 is fine if you want to keep that connection balanced, I dont know that youll hear an audible difference between the $10 dac, so you could start cheap with the $10 dac and upgrade it later, and then have a point of reference for comparisons between technology and components. Truly balanced looks like this:
Jitter is typically worsened by signal transmission, and more so by optical, but corrected with upgraded crystal oscillators(tcxo, ocxo, crystek) and low output impedance low leakage low noise power supplies. Audiogd has a new design for the power supply for the dac chip that provides great results for delta sigma dac chips.
"3,Another two groups are the OPA + discrete transistor serve regulators, its output ripple far lower than 1uV, they powered supply for the Left and Right channels of ES9028 PRO built in DACs separately . Compared to the ultra speed regulator, the serve regulator can improve the sound quality much better on detail and dynamic . The L and R separate power supply boost the sound stage much wider and deeper . The very pure power supply let the unit has very good performance on jitter reject !(test with TCXO built in unit)"
or just use r2r/multibit (・。・) Im suprised I havent gotten yelled at yet lol maybe im on ignore ;[
I have a second system thats not currently in use now but it used a pc, usb to an uptone usb regen powered by a jameco lps, into a breeze duu8(lps with a tcxo), optical to an audiogd nfb11(lps with discrete regulation and tcxo) with a vh audio flavor2 or 4 power cable(the wire geometry reduces noise generated by the varied current draw of digital signals) on a small topaz line noise suppressor(completely knocks common/traverse mode noise and provides surge suppression). Very very good clean sound, I bought everything used for about $300 and it outperformed some very expensive equipment and was bested only by the balanced audio gd setup with upgraded usb transport.
But really the odds of you hearing increased jitter from optical vs the noise that comes with using usb is much less. We dont hear jitter or distortion or noise generated by leakage as audible noise, we hear less detailed, less natural audio and the leakage and noise from the pc and the poor signal quality of usb makes for worse sound quality compared to optical.
Like I said though, alot of that equipment isnt wire with gain, its multiple iv conversions and feedback loops to drive down distortion, snr, and flatten the frequency response. I know it probably doesnt looks like anything but these diagrams show what wire with gain looks like:
audiogd acss path:
thx aaa 789:
All those parts in the audio gd dac up top is power supplies and discrete regulation, the actual signal path is very short. If you want a dac with no influence its r2r/multibit again, non oversampling fpga controlled discrete r2r or pcm1704uk would be the goal there. That being said single chip ess90x8 dacs sound good and so do modern feedback amplifiers, just like vinyl and tube amps sound good, you really cant go wrong with modern audio equipment, but you can tailor your sound and upgraded equipment provides draw dropping transparency/imaging/staging. The best description is that delta sigma dacs and feedback amplifiers are more froward sounding, they can sound a bit faster and perhaps more detailed, whereas multibit and nfb does micro detail or natural reflections in the recording are more accurately rendered that contributes to staging and imaging better and the audio takes on more depth and space, things like solo recordings of an acoustic piano or cello take on an eeriely realistic quality.
For external effects on cabling rca is the worst, very susceptible to emi/rfi. XLR being balanced is better, quadrapole xlr even better still due to the nature of the wire geometry. Current signal like Krells cast or Audio-GDs acss is immune and sounded much better than a good xlr connection. Confirmed audibly between the audiogd components, which also have improved rca/xlr outputs. Ive never heard much difference in cables to the headphones/speakers, just use quadrapole and gauge relates to length, i.e canare 4s6 for a short run or 4s12 for a long run.
Balanced is beneficial for cabling between components, for the actual headphones though balanced either provides additional power, which is very useful for planar magnetics, or it removes any crosstalk, which is more useful for binaural rendering that depend on accurate stereo imaging. So not necessarily something you have to be concerned with either. Single ended to the headphones will sound just fine, Meier is a testament to that, http://www.meier-audio.homepage.t-online.de/