going crazy

.. i noticed that something annoying me when my synths goes through "ad/da-> headphones" of profire 2626....after a little test i noticed a strange behavior at different samplrates..test : synth -> analog in ->headphones and changing 44-48-88-96 and so on (in pauses listening from direct headphone out on synth for clean signal reset in head)
, at 48 and 88 there is a little bit extra

something strange like resonances or something else in the upper mid/high frequencies which irritates and tired ears..at 44 and 96 I don't feel it,

confused what exactly gives such an effect..I dont want to record at 44 but 96 is to much for system

never noticed this effect before, looks like I'll have to buy another soundcard for testing da conversion... has anyone noticed something similar????????