Yesterday, while trying to figure out why a computer didn't produce sound, I dropped by MP3.com to get something to play. A new song by Nelly Furtado, "Powerless," was promoted on the front page. As it turned out, the speakers don't work, but this morning I listened to the song on another...

Yesterday, while browsing through the audio test equipment at PartsExpress, I came across the Gold Line HPAJr. It is a portable headphone amplifier in an aluminum enclosure with quarter-inch input and output jacks. It feeds off two 9V batteries or a 12-18V power supply, and has adjustable input...