Headset ohms?

What you're talking about has to do with a bunch of things:

- sensitivity (loudness relative to impedance) 
- impedance (measure of electrical resistance) 
- power handling (measured in Mw) 
- computer audio sound cards (mostly unique)

Lower impedance headphones require more current. Higher impedance headphones require more voltage. In other words, something that is 65 ohms and above would benefit from a headphone amplifier. 

It should not get damaged. However, if there is the option to increase the impedance on the sound card, then use it. Doing so is beneficial for the performance of the headset.

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