[streetknight]

OK i am getting the Beyerdynamic DT 250-250, and i wanted to make a pocket amp. just wondering if i would need to change any resisters to accommodate for higher impedance headphones? also take it easy on my this is my first amp i built.

 

[till]

IMO this is a matter of taste. I do not listen at very loud levels, so a gain of 6 is plenty for me with the DT250-250s (I change R3 to 2K instead of 1K). Other people might disagree and recommend the standard gain of 11. Also, higher supply voltage is better for high impedance headphones, so you might want to use two 9 V batteries in series instead of one. But again, YMMV.
HTH
Till