[jamesino]

I purchased a Magni/Modi stack for my Senn HD 650 and am not as impressed as I hope to be. I would like a more pronounced emphasis on vocals. 
 
I'm thinking of upgrading either the Magni or the Modi to either the Asgard 2 (amp) or Loki (DAC), respectively.
 
Which one would you guys recommend? Would I notice more improved vocal performance in my songs if I upgrade the amp or the DAC? 
 
Alternatively, do you guys think the Magni/Modi combo needs some burn-in time, despite being solid state?

 

[pwwaring]

The Loki is DSD only - you'd need to look at the Bifrost if you wanted to upgrade the DAC within the Schiit line.  
 
As for the rest of your questions, hopefully someone with a lot more knowledge chimes in, but how much the vocals will improve, relatively speaking, by upgrading from the Magni/Modi stack is questionable - it could be more of an issue with the source material and sound signature of the HD650s.

 

[PurpleAngel]

  I purchased a Magni/Modi stack for my Senn HD 650 and am not as impressed as I hope to be. I would like a more pronounced emphasis on vocals. 
I'm thinking of upgrading either the Magni or the Modi to either the Asgard 2 (amp) or Loki (DAC), respectively.
Which one would you guys recommend? Would I notice more improved vocal performance in my songs if I upgrade the amp or the DAC? 
Alternatively, do you guys think the Magni/Modi combo needs some burn-in time, despite being solid state?

It usually works best to turn the volume up to max on your source and just use the Magni's volume knob to adjust volume.
 
What is your source?

 

[jamesino]

I'm listening to flacs via Foobar

 

[Sony Slave]

I'm listening to flacs via Foobar

 
If you're really serious about upgrading the sound of your audio equipment...I'd advise you to upgrade to the Schitt Bi-Frost DAC. I've read a review where the person says that DAC adds soul to the music, something that the modi couldn't possibly do. (He owned both)
 
If you want to save a little money, you can do what i'm doing. I'm buying a Modi and a Little Dot 1+, the little dot's stock tubes will be replaced with the Voshkods and the OP Amp will be replaced with the OP2107AU

 

[jamesino]

   
If you're really serious about upgrading the sound of your audio equipment...I'd advise you to upgrade to the Schitt Bi-Frost DAC. I've read a review where the person says that DAC adds soul to the music, something that the modi couldn't possibly do. (He owned both)
 
If you want to save a little money, you can do what i'm doing. I'm buying a Modi and a Little Dot 1+, the little dot's stock tubes will be replaced with the Voshkods and the OP Amp will be replaced with the OP2107AU

 
So  Magni + Bifrost would be better than a Asgard 2 (or Valhalla) + Modi?

 

[Sony Slave]

   I would like a more pronounced emphasis on vocals. 
 
 

To answer you title question: Keep the DAC and get a Little dot 1+
To answer your quote: Little Dot 1+ with the EF95 tubes in this thread should help you out.
Also swapping out the op amp in the Little Dot 1+ will help as well. The OP2107 is mid range orientated.  
Look for the  Voshkod 6ZH1P-EV and the  Mullard M8100 / CV4010
http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide
 
Will the Little Dot 1+ power your headphones properly?
The Little Dot 1+ specs say 150mW at 300ohms.
 
Hope this helped.

 

[PurpleAngel]

   
So  Magni + Bifrost would be better than a Asgard 2 (or Valhalla) + Modi?

Go to this thread and read all 919 pages of people who own the HD650 and see what they think is a good amplifier for the HD650.
http://www.head-fi.org/t/197776/sennheiser-hd650-appreciation-thread
 
My two cent is you might do better with upgrading the amplifier, over the DAC.
As a wild guess for an amplifier, the Little DOT MKIII, $240?

 

[Sony Slave]

  Go to this thread and read all 919 pages of people who own the HD650 and see what they think is a good amplifier for the HD650.
http://www.head-fi.org/t/197776/sennheiser-hd650-appreciation-thread
 
My two cent is you might do better with upgrading the amplifier, over the DAC.
As a wild guess for an amplifier, the Little DOT MKIII, $240?

 
I just about to say that, get the MKiii if you have the money or even the MKIV.
 
But I thought you were on a budget, so I did not bring it up.