I have always found using the magic wand to create a selection a bit, well… troubled. Some people call it the “tragic wand.” In some circumstances it works well. In others, not so.
Here’s the best way to grab a selection, especially when you are trying to grab graphic elements that have transparency around the edges or in the line itself (for example, a logo or signature):
Go to the Channels panel. Select the channel(s) you want. At the bottom of that panel click on the dotted circle tool (to the left), which loads the channel(s) as a selection!
You may need to invert the selection before copying/pasting it into a new document.
Here’s an resulting example: my “T.”