[Michael V]

  No. Any difference there would be between optical and USB would be much, much, much smaller than the difference between using your internal soundcard and using an external DAC and a tube hybrid amp. If you can't hear a difference between these two setups with optical, you won't hear it with USB. 
 
(And it's totally reasonable not to hear a difference, if your computer was providing enough power to drive those headphones well at the level you listen to.)

 
 

  The Xonar is pretty good as far as sound cards go. 
 
Just give your brain and ears time to develop. There will be very slight differences that you will begin to perceive. Have one reference track that you know inside and out. Listen to the small details. The etching in the track. The high pitch from a triangle. Or the rub of fingers on a guitar string. The decay of a piano note. Focus on them. Listen to it again and again over days and weeks.
 
Then change sources. 

 
 

 
The 650's are not the greatest resolving cans out there, but listen for the little things, soundstage/imaging cues, brush strokes on cymbals, an acoustic bass, plucked or picked, speed, dynamics, contrast between notes, decay, pick a couple of favorite, well known songs and A/B them  (pick some well recorded acoustic).

 
 
I'll just let it break in and see how it is in a week in a half and decide from there.

 

[rovopio]

my grado sr60 doesn't sound any different either plugged into ODAC or fiio e12 or straight from my PC.
 
sure if i nitpick, the bass is better, the speed is even faster, and the soundstage a little better. but really, not by much.
 
i think that's what you're experiencing right now. something definitely changes, just not as much as you previously expected.
 
burning in (and for a week), won't change much, definitely won't change from zero to 60. your brain however, will get used to the sound and will appreciate it more. brain has ability to adapt. at the end of the week, you will find the 650 better from your stack because your brain are used to it, rather than it actually changes that much within the week.
 
it won't change that much.

 

[Pirakaphile]

my grado sr60 doesn't sound any different either plugged into ODAC or fiio e12 or straight from my PC.

sure if i nitpick, the bass is better, the speed is even faster, and the soundstage a little better. but really, not by much.

i think that's what you're experiencing right now. something definitely changes, just not as much as you previously expected.

burning in (and for a week), won't change much, definitely won't change from zero to 60. your brain however, will get used to the sound and will appreciate it more. brain has ability to adapt. at the end of the week, you will find the 650 better from your stack because your brain are used to it, rather than it actually changes that much within the week.

it won't change that much.

At 32 ohms impendance, I'm sure your computer has a pretty easy time driving your grados, but I found that the difference between my headphone out and Magni/Modi stack was a pretty big change for the better. However, high impendence cans, and power hungry orthos almost certainly need extra amplification. Try to play the HiFiMAN HE-6 from anything other than a powerful amp and you're sure to get a terrible result.
In retrospect, most popular headphones are easy to drive and have low impendence, which is what laptops, cellphones, and media players are designed to drive.
You'll only hear a difference if you're looking for that difference, and as an audiophile I can certainly hear a difference in amplification due to the fact that I've got exceptional hearing.
Whew, what a blab I can be

 

[rovopio]

At 32 ohms impendance, I'm sure your computer has a pretty easy time driving your grados, but I found that the difference between my headphone out and Magni/Modi stack was a pretty big change for the better. However, high impendence cans, and power hungry orthos almost certainly need extra amplification. Try to play the HiFiMAN HE-6 from anything other than a powerful amp and you're sure to get a terrible result.
In retrospect, most popular headphones are easy to drive and have low impendence, which is what laptops, cellphones, and media players are designed to drive.
You'll only hear a difference if you're looking for that difference, and as an audiophile I can certainly hear a difference in amplification due to the fact that I've got exceptional hearing.
Whew, what a blab I can be

 
basically what i was saying to michael V is that, waiting burning in a week won't help changing their equipment from zero change to significant of change.
 
it'll just change how their brain adjust to the sound. brain burn-in so to speak. it will sound better at the end of the week, not because burn-in but because the brain adapts to the sound.
 
as for you, if you like high fidelity sound like most people that register here ofc you will hear differences between hd650 straight from a PC and from schiit stack.
what i meant when i said "i think that's what you're experiencing right now. something definitely changes, just not as much as you previously expected." to them was, people have different standards and expectations on how significant a change are.
 
i'm not saying there's little benefit to dac and amp. of course if you are into good reproduction of sound, the money spent on the DAC and amp will yields significant return on better reproduction of sound.
 
But how significant a change people feel they experience is largely subjective.
Probably what you (and i) consider large difference, would be considered non-existent by others.
 
as for myself, using the magni 2 uber, there's a difference between PC to fiio e10 to magni 2 uber. also the more i pay attention to the details of the songs, the more i notice those differences.
i couldn't write off my relatives opinion either when they said there's no difference between plugging in that grado direct to PC or through the magni 2 uber.
 
even more blab than you. all's good. haha

 

[money4me247]

  Hmm. It's just weird because when I upgraded from the bravo audio v3 tube amp to the lyr 2 I heard a discernible difference. But going from the asus xonar stx soundcard to the bifrost uber/lyr 2 stack I don't hear a difference at all. And somehow they all sound the same whether I plug the headphones straight into the computer, into the soundcard, or into the schiit stack. 

hey! I did the same upgrade path for amplifers: Bravo V3 into the Lyr 2!!! and ya, the Lyr 2 was an noticeable improvement for my HE-560s. However, for some of my other headphones like the ATH-M50x and the HE-400s, it honestly was pretty much the same sound. If there were any sonic differences, they were too subtle for me to clearly identify.
 
For the bifrost, the improvement in sound quality was noticeable on my HE-560. Haven't really been listening to my other headphones enough to do a comparison between no bifrost vs bifrost.
 
That's why I personally believe that investing a really nice headphones is the most important first step before getting nice components.
 
Not sure why it all sounds the all the same. If your soundcard doesn't output through your computer headphone jack, you should be able to tell a difference there at least. what kind of internal sound card does your computer have?
 
And finally, I agree with what the poster above said. if you hear differences over time, it is more likely to be your brain adjusting to the sound rather than burn-in.

 

[scizzro]

  I've been doing some A/B testing between plugging my headphones hd 650s straight into my computer and plugging it into the bifrost uber/lyr 2 stack and I'm literally not hearing any differences in sound quality at all.

scary.. now I'm second-guessing upgrading my sound card to a bifrost

 

[hifi nub]

Any lyr 2 owners know what the trimpots are for that are on its board?
 
I see two of them.
 

 

[john57]

it might be for the DC level offset  for the servo's would be my guess like on my LD VI+. In the past I find that Schiit is quite good in answering technical questions. 

 

[Rem0o]

Yup, seems like bias adjustment or DC level.

 

[BobFiggins]

I have a question, I have a SPDIF connection for my motherboard, will this input into the Modi 2 Uber?
 
If so, would this be a good cable to use for it?
http://www.monoprice.com/Product?c_id=102&cp_id=10229&cs_id=1022901&p_id=1419&seq=1&format=2
 

 

[madwolfa]

  I have a question, I have a SPDIF connection for my motherboard, will this input into the Modi 2 Uber?
 
If so, would this be a good cable to use for it?
http://www.monoprice.com/Product?c_id=102&cp_id=10229&cs_id=1022901&p_id=1419&seq=1&format=2

 
Yep, it would work.

 

[hodgjy]

   
 
If so, would this be a good cable to use for it?
http://www.monoprice.com/Product?c_id=102&cp_id=10229&cs_id=1022901&p_id=1419&seq=1&format=2
 
 

I've used Monoprice optical cables for years in all kinds of devices, and they've been just fine. Make sure you get the shortest length possible and don't twist the cable or kink it at all.
 
Optical is actually my preferred connection over coaxial and usb. I know all about the jitter, but I think it's more beneficial to remove the electrical connection between devices. Gound loop hums like to pop up in my apartment from time to time.

 

[Pirakaphile]

Alright, I had a nice neat plan for my audio plans until now, when I decided to get the Audeze LCD2, and now I'm wondering if I should skip Lyr2/Bifrost and try to go straight for Mjolnir/Gungnir combo for my end game setup.
I'm also at a loss as to what I should get first, the Audeze, or the Schiit. I've already got my HiFiMAN HE-500, so I don't need to upgrade headphones immediately, but the Audeze are also going to take two years of saving up. $500 a year limit.
Feh, all this effort for my music listening pleasure better be worth it in a decade.

 

[hodgjy]

Alright, I had a nice neat plan for my audio plans until now, when I decided to get the Audeze LCD2, and now I'm wondering if I should skip Lyr2/Bifrost and try to go straight for Mjolnir/Gungnir combo for my end game setup.
I'm also at a loss as to what I should get first, the Audeze, or the Schiit. I've already got my HiFiMAN HE-500, so I don't need to upgrade headphones immediately, but the Audeze are also going to take two years of saving up. $500 a year limit.
Feh, all this effort for my music listening pleasure better be worth it in a decade.

 
I say save your scratch and get the Lyr2/Bifrost. Put the money you saved into more music. Many people here think the LCD/Lyr/Bifrost is endgame. 

 

[madwolfa]

Alright, I had a nice neat plan for my audio plans until now, when I decided to get the Audeze LCD2, and now I'm wondering if I should skip Lyr2/Bifrost and try to go straight for Mjolnir/Gungnir combo for my end game setup.
I'm also at a loss as to what I should get first, the Audeze, or the Schiit. I've already got my HiFiMAN HE-500, so I don't need to upgrade headphones immediately, but the Audeze are also going to take two years of saving up. $500 a year limit.
Feh, all this effort for my music listening pleasure better be worth it in a decade.

 
Dunno, man. What don't you like about your current setup? Or is it just a simple case of upgraditis?
 
EDIT: I also think that Lyr 2 / Bifrost would be sufficient for either HE-500 or LCD-2.