glowing ears

So the sound card does what it should, it brings the sound to the speakers / headphones, but something seems to have gone horribly wrong here. I have read such problems already at the reviews of other USB sound cards and could imagine that not at that headphones can be warm. Unfortunately I had after 1 1/2 minutes notice during operation that this occurs exactly at me.

Configuration:
- MacBook Pro
- USB soundcard
- Sennheiser In-Ear Headphones

After hearing about 1 1/2 minutes on music I had the strange feeling that my ears are warm. Have the headset briefly taken out and "touched", in fact, which are warm. Did they then still further tried another 2-3 minutes, then it was me but too unpleasant. Not that the headphones would be hot, so you would have to worry about burns or melts the plastic, but it is very uncomfortably hot in the ear. By the way, I can not imagine that such a heat development is good for the life of me headphones.

I am absolutely dissatisfied with the product, therefore, since I can not use it for my purpose and therefore the sound card goes back to Amazon.