[HKondor]

  A mid-sized Audio-gd unit would do it, or a Geek Out 450. The HD-600s can be pushed pretty far. I found they get more of a kick in the pants with initial upgrades then start to get more spacious as you get very serious, but you'll hit a resolution wall eventually. I wouldn't be surprised if, where you're at, the DAC in that XiangSheng is most of the problem. 

Thanks! I'll put the Geek Out into the mix.
 
My hypothesis too...the source looks like the weak link on the rig right now. I'm curious to see what differences I'll find once the new DAC is in place.
 
The DA-03A/MS-1 rig was good to introduce me to the hobby, but in hindsight I should have gone higher end right from the start. Gave the MS-1s to my cousin on long term loan...

 

[HKondor]

Double post - sorry. Still getting the hang of this.

 

[Phishin Phool]

Several hours of listening today and they were as I remember them from a head-fi meet a few weeks ago. Splendid, they are probably the most accurate and resolving cans I own atm. Hated to give up my Denon D2000's but to get the HD600s well worth it.

I never really use the headphone out on my DAC but when somebody else wants to plug in it is nice to be able to play 2 cans simultaneously albeit 1 ss and one tube. In a vacuum I would recommend an audio gd 7 as a standalone

 

[HKondor]

Cool, I'm glad you liked them. Are they your best cans right now or do you prefer any other from your collection? 
 
I initially bought the general advice of different cans for different flavors on logic, turns out after getting the HD600s I don't listen to any other phone unless I need to -SE215s commuting-. I'd like to see how far the HD600s can go.

 

[Phishin Phool]

I.really like my beyer dt990s as well. They are fun with a U shape.sound but the soundstage is awesome.
I have a fiio amp on the way for at work or elsewhere outside my home to drive the Senn.

 

[eljustinoid]

I used to own a Little Dot 3, very stupidly sold it.

I have the Dac-01a and it's a great preamp but the headphone sound is to-do.

If you want great headphone sound, get a little dot 3 and decent DAC, I'd suggest an HRT streamer II or schiit modi for starters.

 

[JoshMo]

@HKondor what did you end up with? I am currently building my crack with speedball and was also looking for a DAC upgrade. Curious if you found a good pairing

 

[reihead]

Same here, curious to know what DAC you went for

 

[JoshMo]

I went multifrost and could not be happier.

 

[reihead]

^^ high on my list but it seems the arcam irdac has similar performance with a better price tag here in Europe.

 

[HKondor]

 @HKondor what did you end up with? I am currently building my crack with speedball and was also looking for a DAC upgrade. Curious if you found a good pairing

I ended up getting the ODAC and it sounds so much better than the original rig. Still feel that there is room for improvement to bring out the most out of the HD600 though. 
 
Life is hard for us optimizers.