Heh,
Glad it helped some. There's a little Opamp chip most likely for the headphone driver. When you double the amount of headphones you lower the resistance. Lower the resistance can make the load more difficult to drive if the circuit can't deliver the current or can't handle the heat load from the increased current flow.


So, I would appoach this with caution if I were the Poster. If I were me, I probably wouldn't do it at all.

The proper way to do it would be with a headphone amp.

If you want to have some cheap DIY Headamp fun, you could go here. This guy is a legend!

http://www.amb.org/audio/


If you really want to see Headamp nutz, go to:

http://www.head-fi.com

It's a sickness!