This is a simple mp3 of a sine wave which can be used for testing:
- Sine Wave 440 Hz (A) for 5 minutes (mp3) - Right click for "Save Link As" (Firefox), "Save Target As" (Explorer), "Download Linked File As.." (Safari) or "Save link as.." (Chrome).
A simple test tone like this can be used with an oscilloscope to troubleshoot analog hardware.
- Load this mp3 onto a media player or just play it on your computer.
- Plug an audio cable from your media player to the input of the audio device being tested.
- Start playing the test tone (loop if possible)
- Trace the sine wave through the analog circuit till it unexpectedly disappears. This will lead you to the vicinity of failure.