You can DIY! The F5 Power Amplifier

In 2008, Nelson Pass submitted an article on its new F5 power amplifier design to audioXpress. At the time, he wrote: “I feel that it’s important to support AudioXpress, a magazine with which I have a 35 year history, and which also serves as a mainstay for the DIY community. Lately they have kindly printed projects that I had already posted on the web, but I decided that they deserve a little better than that.” Effectively, the F5 project was published in May 2008 and had a huge impact on the global DIY community and certainly contributed for the fact that audioXpress is still around today.

In this fascinating article, published in audioXpress, October 2004, Nelson Pass investigates loudspeaker performance when driven by a current source amp. This extensive research shows what Pass and Kent English found with a variety of full-range sensitive loudspeaker drivers when they drove them with an active current source and played with parallel networks to shape the response to their liking.

In this article published originally by audioXpress in March 2005, Nelson Pass offers a series of tips about designing filter networks for both voltage and current sources. Nelson Pass provides filter examples that can be used equally well with a voltage or current source.

What can you do to ensure the best possible sound from your system? According to Nelson Pass, the “sweet spot” concept is generally regarded as “that happy balance of conditions that elicits the best possible sound,” including the interiors of the components themselves. This article was originally published by audioXpress, January 2010.

In this much sought after modification project, Nelson Pass rekindles his desire for the JBL L300 Summit loudspeakers and completes a renovation. As he explains, “it is not a trivial task to improve on original JBL design." "I think I’ve managed to respect the JBL legacy while tweaking the sound to reflect the tastes of the 21st century.” Article originally published in audioXpress, January 2012.