You can use the amp for headphone or earbud. I designed it for my earbud. I buy them at dollar tree for a $1 each. They have headphones too, I like the ear bud better. Any way I ran the sim for both so you can see how that works.
I have been using this amp to drive a single earbud. The plug was bad on the bud so I split the cord and made 2 singles. The little amp drives the single bud very well.