It can convert from 1/8" or 1/4" stereo to either 1/8" or 1/4" mono (with the option to change jack sizes between channels). It can do simple conversion from 1/8" to 1/4" in mono and stereo. It can even split a mono signal into a stereo signal (again, with fully selectable 1/8" and 1/4" conversion options).
It is my hope that I will never need to make another converter again!
Well... until I need two of the same kind.
Step 1: Go get stuff
A 14" x 12" sheet of white acrylic.
An awesome Epilog laser cutter
Red and blue acrylic paint
A paintbrush, water cup and palette
A heat gun
Heat protective work gloves
An 18" metal extrusion
A drill with a 1/4" bit
(x2) 3" carriage bolts
(x2) 1/4" nuts
(x2) rubber stoppers
(x6) 1/4" mono jacks
(x3) 1/4" stereo jacks
(x6) 1/8" mono jacks
(x3) 1/8" stereo jacks
(x4) SPDT rocker switches
A DPDT slide switch
A soldering setup
If you don't have a laser cutter, you can use a service like Ponoko
Step 2: Laser cutter - the tool of the future
Using the files below, first make a raster cut with the following settings:
Then make a vector cut with the following settings:
Step 3: Paint
Place it elevated and flat so that the edges don't touch anything and you can pick it up from underneath if need be. I balanced mine on top of my water cup.
Wait for it to fully dry and then peel away the protective coating.