[davidsh]

In short, I think the recommendation is to get an amp to go with a D1 or DX. 

 

[foreign]

The asus stx is a great product it will suite your needs and is at a very good price. I used it for the past 6months. That being said an external amp & dac is also a viable option. I experimented a little bit and use a tube amp and external dac for music it is a slight improvement over the stx but it did cost in excess of $600. When I purchased the senns hd650 I noticed a bit of fatigue when using the stx. The tube amp alleviated this problem. I did try cheaper amps and dacs but couldn't really hear an improvement over the stx.

 

[N3wKids]

Quote:

The AKG K551 is a 32-Ohm headphone, which means it would be better to have a headphone amplifier with an output impedance that is 4-Ohm or less, the Essence STX has a 10-Ohm output impedance.
(I would assume the K551 would still sound fairly good plugged into the STX).
 
A Schiit Magni external headphone amplifier, $99, has an output impedance of less then 1-Ohm.
So the Magni would be preferred over the STX for driving 32-Ohm (K551) headphones.
The Xonar DX & D1 use the same audio processor (CMI8788) as the STX, so they all come with the same features (Surround Sound).
The Xonar DX & D1 do not come with a headphone amplifier, but sell used for around $50.
So a Xonar DX or D1 (used) with a Schiit Magni headphone amplifier should make a good combo, for use with the AKG K551.
And as the Magni is external, it can be used with more stuff besides the computer.

I think I'll go with this. 
Thank you for the suggestions :3
+1
EDIT: Can't get the Schiit in Canada ): Any other amps?

 

[PurpleAngel]

PAV2V (Pocket Amplifier 2 Version 2), sells on eBay for around $60-$65, ships from Canada.
Can work off AC or battery.
 
eBay seller
http://myworld.ebay.com/grans-ar/
 
Seller's internet website.
http://www.electric-avenues.com/amplifiers.html

 

[N3wKids]

Quote:

PAV2V (Pocket Amplifier 2 Version 2), sells on eBay for around $60-$65, ships from Canada.
Can work off AC or battery.
 
eBay seller
http://myworld.ebay.com/grans-ar/
 
Seller's internet website.
http://www.electric-avenues.com/amplifiers.html

Cool, thanks!