Speakers: Parts Is Parts - High-Polymer Film, The Lost Speaker Technology (Part 1)

This article explores Polyvinylidene Fluoride Film (PVDF), a piezoelectric polymer used in various transducers for headphones, microphones and loudspeakers. It seems that the audio engineering community at large is either not familiar with PVDF film or misunderstands PVDF piezoelectric film technology. Hopefully, this article will serve as an introduction (or reintroduction) to the technology. This article was originally published in audioXpress April 2013.

Where do tubes come from? In this article Richard Honeycutt revisits the history of tube electronics, from its early invention to the widespread adoption in radios and television receivers. And because familiarity simplifies tube selection, the article explains where some of the most common tube types can be applied in todays designs on power amplifiers and pre-amplifiers and tube stages. This article was originally published in audioXpress, April 2013 as part of the Hollow-State Electronics monthly column by Richard Honeycutt.

Recently, I got bitten by the nostalgia bug and picked up a pair of old factory-wired Dynaco ST70s in pretty nice condition. On one of the Dynaco ST70s, I installed a new 6GH8 driver board instead of dealing with the rare 7199 issue, and I designed a small (3” × 3”) PCB to combine the bias supply and added the LED bias-setting circuit. This article was originally published in audioXpress, April 2013.