Actually, if your boombox has a polarized jack, you should probably ONLY use a polarized connector. It's more for safety reasons than damaging your equipment. One of the pins is hot, and the other is neutral. In other words, one of those pins will electrocute you and the other, you can touch without harm. For electronic equipment that does not bond ground to neutral, you are OK. But if it does, it could pose a huge safety hazard. In general, boomboxes are double insulated and probably does not matter but it's better not to presume that fact and give it the polarity it wants. There is a reason the cord is polarized. If you check at the plug end, you will also see that one tab is wider than the other tab. That is so the cord maintains the proper polarity at both ends. Not many boomboxes use that type of polarized cord. The kaboom is one.
