Amplitube on the iPad 2A few months back, I purchased the ultimate unnecessary-but-awesome gadget: the iPad 2.

With the availability of apps like Amplitube, AmpKit, and Garage Band, it’s immediately obvious how this device can be an amazing guitar learning and practicing tool.  I’ll talk more about that in another article.   But before you can plug in your guitar, you need a special interface…

In part 1 of this 3-part video series, I introduce the project- how to make your own impedance matching, buffered guitar interface for the Apple iPad, iPod touch and iPhone.   These iDevices all share a similar headphone/microphone jack specification, so this circuit should work with all of them.

I’ll show you why a simple unbuffered cable interconnect will sound terrible- because of the significant impedance mismatch between a passive guitar circuit and the iDevice mic jack.  Also, the iDevice provides a 2.8V DC on the mic input to drive a microphone preamp, and as you’ll hear, this voltage totally screws up your guitar circuit.

This isn’t intended to be an ultra-high-fidelity interface. But trust me, it sounds good and costs very little. And the principals learned in this simple electronics project are the same as those required to make a guitar boost pedal like the Fulltone Fatboost.

In parts 2 and 3, I’ll explain all the electronics and show you how to assemble the interface, but for now, let’s get started:

And here’s some of the things you’ll need:

A 4 conductor cable, like these.  Note the tip-ring-ring-sleeve connector:

4 conductor TRRS cable4 conductor TRRS cable - like an iBook audio/video cableTip ring ring sleeve connector

Also, a female 3.5mm phone jack for your headphones, and a 1/4” female jack for your guitar:

3.5mm female phone jack for headphones1/4" female phone jack for the guitar

I’ll cover the electronics components in part 2.

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Filed under: Geek • Guitar