The value of your upvote is dependent on your Steem power only.
Upvotes to your posts comments will increase your reputation based on the Steem power of those upvoting.
I guess technically you can up your rep by voting on yourself but couldn't say for sure.
The reputation of those upvoting is also important.
That's interesting, I thought it rested solely on the stake of the user.
I'll have a look into this further. Thanks for the info.