You can DIY! Build an Audio Dummy Load

An audio load is an essential piece of test equipment for any audio electronics workshop. Having created the very popular Heathkit ID-5252, more than 35 years ago, Gary Galo decided to design a new option for everyone to build now. The ID-5252 contains four 8Ω, 60W power resistors. The biggest limitation of the Heathkit load is power handling. Series and parallel combinations can be used to produce various resistances and power levels — up to 240W at 8Ω, using all four resistors. But, simultaneously testing both channels of a high-powered amplifier requires two ID-5252 units. Fortunately, the raw parts for building an audio load are easy to find.

Bruce Brown explains his successful method of rebuilding a vintage W-7 tube amplifier from Heathkit. As the first power amplifier that broke $1 per watt barrier of listening power, the Heathkit W-7 was a major breakthrough for audiophiles. Introduced in 1958, it carried a list price of $54.95. This article was originally published in audioXpress, May 2007.

The new edition from audioXpress is available, and there are many reasons to quickly get to it. Our main cover article is an in-depth review of the Benchmark AHB2 Stereo Power Amplifier by Gary Galo. If you are interested in amplifiers, this review will clearly explain why you should listen to this one. On another serving from our series on Wireless Audio development platforms we focus on CSR. And much more…