[sudenuni]

Hi,
 
I'm going to buy a sennheiser HD600 very soon and it will be plugged into my external soundcard Presonus FP10 :
http://www.presonus.com/products/fp10
 
I'm however little concerned about impedance, here's the tech spec of the Presonus FP10 headphone ouput :
 

Headphone Output
Type	TRS Active Stereo
Maximum Output	150 mW/CH @ 60 Ohm Load
Frequency Response (±1.0 dB)	20 Hz - 20kHz

 
I'm thinking about buying an headphone amp that would fit in a 19" rack (with an adapter like this if necessary) because it will be very much more practical in my home studio. I need at least 2 headphones outputs (one for the sennheiser HD600 and one for my good old sennheiser HD25)
 
Do you know a good headphone amp which meet these requirements... and not too expensive ?
 
Thanks.