[Airwolf]

Budget: Up to $300 USD - Willing to buy used
 
I am looking for a USB connected desktop DAC for my PC that offers better sound quality than my onboard sound and the ability to use an equalizer in Windows 10. I do not have room inside my case for an expansion card with my current motherboard and SLI graphics configuration. I am looking for something that doesn't use a lot of CPU time and is a DAC only, as I have a Schiit Asgard 2 headphone amp already. I was using a Soundblaster ZxR card, but it just won't fit anymore without killing the cooling of my graphics cards. Also, Creative Labs makes the world's most awful drivers.

Gear that would be used with DAC:

Schiit Asgard 2 Headphone Amp
HiFiMAN HE-400 Headphones *primarily use these
Sennheiser HD-650 Headphones
Beyerdynamic DT-990 Pro
Audioengine A2 desktop speakers (hooked to line out of Asgard 2 amp, self amplified)

I will be using the DAC for FPS gaming, TV & Movies, deep house and chillout electronic music.  Having virtualized surround in games would be a nice addition, but I am perfectly happy with stereo.
 
Example music:
Axel Thesleff - Sun Goes Down 
Mr FijiWiji & Tülpa - Sentient 
London Grammar - Metal & Dust (Friend Within Remix) 
The Discipline - Move With You 
Yuna - Lullabies (Myles.William Remix) 

 

[k4rstar]

Why don't you just get a Modi 2U and use a system-wide parametric EQ such as Equalizer APO with PeaceGUI?
 
If you want virtual surround you can use something like Razer Surround.

 

[cel4145]

Asus Xonar makes USB sound cards that have digital output. You could get the Xonar U3 for it's Dolby virtual sound, then use a Schiit Modi 2 with optical to connect to it. Creative Soundblaster may have something similar (not sure).

 

[Airwolf]

I think I am probably going to go with the Modi 2 non-uber.  As far as I can tell, there isn't much benefit (if any) going to the Schiit Bifrost or another more expensive DAC.

 

[theveterans]

 As far as I can tell, there isn't much benefit (if any) going to the Schiit Bifrost or another more expensive DAC.

 
It's not that there isn't much benefit, but you'll realize that it's actually quite noticeable on a good pair of headphones and a decent solid state amp such as the Asgard 2. To be honest, in Schiit's DAC line, the more expensive you go, the bigger the delta improvement except for gungnir multibit to Yggdrasil upgrade. For instance, going from modi 2 to bifrost multibit has a noticeable improvement right off the bat, but going from bifrost multibit to gungnir multibit makes that improvement greater than the modi 2 U to bifrost multibit. However, Gungnir multibit to Yggdrasil is a smaller delta than bifrost to gungnir.
 
TLDR: You have to spend 10x the Modi 2's price just to get a satisfying improvement in a DAC

 

[PurpleAngel]

  I think I am probably going to go with the Modi 2 non-uber.  As far as I can tell, there isn't much benefit (if any) going to the Schiit Bifrost or another more expensive DAC.

 
The Modi 2 (non-Uber) is USB only and USB bypasses the computer's on-board (or add-on) sound card.
Where as a DAC with a S/PDIF (optical or coaxial) connection can work with sound cards.
Hifimediy optical DAC, $59
http://hifimediy.com/DACs/ready-made-dacs/SPDIF-9018-DAC
 
If you have no interest in using sound card features, then USB is fine.