Are you having a hard time finding out what component is failing or broken in your pedal project? This is where an audio test probe can be extremely valuable and easy to isolate a problem.

The Rattlesnake Audio Probe is a great tool for you DIY effect builders and modders out there. It allows you to probe the circuit, establishing breakpoints that let you know what the circuit is doing audibly. Following breakpoints is a great way to identify bad components or where their circuit is failing.

You connect a cable from the amp's input to the 1/4" jack on the probe. Connect a cable from a guitar or signal generating device (could be a looper or instrument) into the pedal's input. Insert the black (ground) probe somewhere in the circuit's ground (usually a screw hole on the enclosure chassis), then touch the red probe to the component. I typically tend to start at the input, which should give you a clean, unaffected tone, then work down the trace until you identify a problem.

The probe is not meant for high voltage devices. The Audio Probe is designed to test simple 9V circuits like pedals.

Please check out the video below. This video shows how I used the Rattlesnake Audio Probe to diagnose a faulty IC in an old MXR Distortion+. The distortion was very "farty," clearly, something was wrong in the circuit. But where? By navigating the circuit, I was able to isolate at the IC. Once I determined that was the problem, I replaced the IC, and the MXR Distortion+ was back to sounding great!