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Build a Line Level to Microphone Adapter - Record from your Phone to Computer or Camera  

DroneBot Workshop
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Joined: 2 years ago
Posts: 911
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Build a simple adapter to use line-level outputs with a microphone input.

Here’s a simple box to solve a common problem - recording audio from your phone or stereo to your computer or camera, when the recording device only has a stereo microphone jack.

I built this device to solve a problem I had recording my videos. I recently purchased an HDMI Capture Device that has a microphone input that allows me to add a voiceover to the videos it captures. Problem was that I wanted to use the output of my microphone mixer to feed the microphone input, but that didn’t work very well (in fact it was awful).

Microphone inputs, such as the ones on computers and DSLR cameras, require very low-level audio signals and the output of a mixer or headphone jack just overloads them. Another problem is that microphone inputs also supply a DC voltage to power the connected microphone and that isn’t desirable when connected to a line-level device like a mixer or tablet or phone.

The solution that I came up with was to build a simple adapter box. It doesn’t require a power source and can be built to suit your specific requirements. In my case, I made it in a small metal box with RCA jacks on each side, but you could use 3.5 mm stereo jacks or even skip the jacks and wire up a cable with the circuit in the middle.

This inexpensive box solved my audio problem and as I couldn’t find a commercial product that performs this function I thought I’d show you how to build one, in case you need to do a similar level conversion.

I built this for less than 15 dollars and most of the cost was the metal box! If you have some parts kicking around you can probably put it together for next to nothing.

"Never trust a computer you can’t throw out a window." — Steve Wozniak