Hello,
 
I have an auzentech x fi forte for a sennheiser hd 650 card. I'm interested in reasonably priced sound cards that also have onboard ampls for high impedence headsets like the hd 650. 
 
I looked at the xonar STX II but thats way out of my price range. I'm more interested in the less than 150 and preferably less than 100 range. 
 
Please assist. 

sunburn74 said:

  I have an Auzentech X-fi Forte for a Sennheiser HD 650 card. I'm interested in reasonably priced sound cards that also have on-board amplifier for high impedance headsets like the HD 650. 
I looked at the Xonar STX II but that's way out of my price range. I'm more interested in the less than 150 and preferably less than 100 range. 

Click to expand...

 
I'm assuming you feel the Forte's amplifier does not drive the 300-Ohm HD650 well enough?
You might find a used Essence STX (original) on eBay, with in your budget.
 
Asus Xonar DX sound card (used, $40-$50) and a FiiO E11K headphone amplifier ($60), makes a nice combo.
 
If this audio improvement is more for music, then just get an external headphone amplifier and connect it to the Forte's Front Speaker jack (green).
The Forte has the AK4396 DAC chip for the headphone output and Front Speaker jacks
Set the Forte for 2-Channel and Speaker output, your music should sound nice and any other medium in 2-channel audio (gaming and movies).
 
Check out Head-Fi's "Amplification for Sale" thread and eBay

How's about the Focusrite VRM box?
 
http://uk.focusrite.com/usb-audio-interfaces/vrm-box/specifications

How about the sound blaster ZX there only about 130. new, you might also consider something used of ebay..