My computer at work didn’t have a 1/4″ headphone jack, so I built simple box that did. It allows me to switch between headphones (1/4″ or 1/8″) or speakers. I also added a volume control for the headphones.
I was emailed by “Nathan” about how a simpler version could be wired that only had one headphone out, and didn’t have a volume control. Here’s a quick sketch for that.
Also, if you want the front always on, and only the back switchable. See the following.
If you're interested in discussing this project or how we could work together, please get in touch at firstname.lastname@example.org