I am looking for a cheap solution to allow me to connect a single set of headphones to two computers I am using. I don't need volume mixing or selection, I just want to merge the two signals.
I found this instructable, that has a very simple design. He essentially connects five jacks ground pins together, and then joins the left and right channels of each input jack to the corresponding pin on the output jack via a 1k resistor.
It almost seems to simple to me. I do not want to blow up the output jacks of my computers by applying an odd signal to them. Is this design safe to use? Can anybody explain what the purpose of the resistors is, and why it works or won't work?