You both don't understand me I think :P
Little example how this works.
You plug a male cable in your female headphone jack(that's how it is called??) on the other side of the cable you have another male plug.
That will go in the input of the amp.
The amp will make it a bit louder higher bass etc. and you can plug your headphone in the amp.
So you use the amp between your psp and your headphone.
My first idea wont work I'm afraid.
My new idea is to make it more portable place it inside the psp and wire it to the headphone output.
This will make it louder and you don't need to carry that small amp with you.(Because it's inside the psp)
I could wire a bigger speaker to it if I can find one that fits my needs.
,k
PS: I apologise for my bad English, I should pay more attention in my English class I guess :P