If you have ever wanted to use your phone or tablet as an amp, but don't feel like paying the ridiculous prices of some adapters out there, hopefully this can help you build your own.

I built my own about a year and a half ago, and it makes for a great way to play. Sometimes I use it to play into headphones so I can jam out without being too loud, other times I use it to treat my phone as my pedals.

Step 1 - Minty Fresh Packaging

Used Altoids container for clean packaging. Drill 3 holes, 1 for a 1/4' plug, 1 for a 1/8" plug and one for a wire exit.

Step 2 - Wire It

• 1 - TRRS connector, which will hook up to your phone. I spliced mine off an old set of headphones with a mic.
• 1 - 1/4" Mono Female Jack (I used a stereo one, but all you need is mono)
• 1 - 1/8" Stereo Female Jack
• 1 - Resistor to prevent input from triggering mic actions, such as stop/play, siri, cortana, etc. (Didn't find the sweet spot, but you want over 800 ohms, I targeted for 1000 ohms and decided to run two 2200 ohm resistors in parallel.)

The wiring went as follows:

• 1/4" Tip -> Resistor Series End 1
• 1/4" Shield -> Resistor Series End 2
• TRRS Tip -> 1/8" Tip
• TRRS Ring 1 -> 1/8" Ring
• TRRS Ring 2 -> 1/8" Sleve
• 1/4" Sleve TRRS Sleve -> 1/4" Tip

I never did finish cleaning up the inside, but threw some electrical tape in there to hold things in place while testing it out. Wanted to make it prettier, but once it was working I couldn't stop jamming on it. I have added prongs on the inside of the lid, where I can wrap the cord on the inside of the case. This let me run my TRRS cord long but I could wind it up on the inside when I didn't need it long, allowing me to keep it from being a spaghetti mess of cables.

Step 3 - Shred it

Hook your guitar up to the 1/4" jack, your headphones in the 1/8" jack and plug the TRRS connector into your phone. The load up the app of your choice, I prefer GarageBand when using my iPhone, but there are ofther great options out there. With GarageBand, just turn on the monitor and it will take the sound in and return it out to your headphones or speaker plugged into your minty fresh adapter.