Q) I'm having feedback issues, a buzzing or humming that I can't get to stop!! What is it coming from, and what can I do to fix it?

  • A)If you are experiencing this, 99.9% of the time the problem is caused by a ground loop. To find out more about ground loops, read this article by Whirlwind USA.


Up to this point, I have been using the setup I describe under the Information section on "How to hook up to a Stadium Sound System". This has worked for me for a couple of years until I recently had a very embarassing situation. During a state championship game, I was unable to play any sounds. The problem turned out to be a bad cable. This led me on a search to reduce the number of cables I use. I wanted to minimize the possibly of one going bad and to reduce the number of spares I need to carry. (I did not have any spares with me during the competition which was a major mistake on my part, never to happen again).

I had been using a Ground-Loop Isolator from Radio Shack (part number 270-054) that retails for around $15.00), it comes with a 1/8" stereo plug to two RCA jacks "Y" cable and the Isolator. This setup worked well for a couple of years but involved the "Y" plug, the Isolator, an adapter to bring the two RCA stero plugs back to a single mono RCA plug, and a cable to adapt from RCA to XLR to plug into my mixer.

On one of the forums that I view frequently, Â (It is a Yahoo Group called Spors-Music_Programming), I found mention of a product by JK Audio called a Pureformer. Here is the link to JK Audio Pureformer. It retails for around $59.00 and uses RCA input and output jacks which still means adapters or conversion cables. It is really a Direct Box.

Another post on that forum directed me to a product called a "Direct Box". Using Google, I found several manufacturers but I liked the one put out by Whirlwind. It is called their pcDI Direct Box. It has a .5mm (1/8") mini TRS stereo input jack and XLR output jacks. This means I only need two cables. A 1/8" stereo mini cable to plug into my pc's sound card and a standard mic (XLR) cable to plug into my mixer. Two cables, very simple. The unit is designed for professional use and is a little expensive (around $130.00) but well worth it if it prevents what happened. I have ordered it and will let you know how it works out. If it does what I think it will do, I will redo my instructions of "How to hook-up to a Stadium Sound System".