Quick Tip: Troubleshooting With a Pair of Headphones

by Scott Helmke – TC Furlong Audio Engineer and Repair Tech

Switchcraft TRS-XLR AdapterHere’s one of my favorite troubleshooting tools:

A pair of headphones (or earbuds) and a TRS to XLR adapter.

A line-level output will actually drive a pair of headphones just fine.  Maybe not audiophile-grade, but certainly enough to hear if there’s signal present or not.

Quite often while testing device outputs, or tracking down where a signal gets lost in a live situation, I’ll just plug in a pair of headphones.

It’s pretty simple:

  • If you hear signal in both sides, you’ve got a nice, solid, balanced signal.
  • If the signal is in just the left ear, then it’s an unbalanced signal.
  • Signal in only the right ear might mean you’re dealing with pin-3-hot gear.

I also check installed cable runs by plugging my iPod into the other end of a cable using another TRS to XLR adapter:

  • If I hear stereo at the other end, the cable is fine.
  • If I only have one ear, then one of the signal lines is bad.
  • If I hear a weird mono, then the ground is bad.

So there you go – a cheap and compact cable trace system!