Linear AC Measurements Using a Diode

Looking for a circuit solution to the problem of measuring AC voltage and current using DC meters? Synchronous rectification solves a pesky problem caused by diodes.

This month we bring you a report on some of the highlights from the Prolight+Sound 2014 show in Frankfurt, Germany. The show provided several innovative proposals for the professional audio industry.

Looking to start a DIY tube amp project without shelling out big bucks? You can do it if you follow a few tips from Bruce Brown, who built a high-quality tube amp for less than $150. His biggest purchase was the “iron.” Here’s how he kept the cost down.

Like many technology companies in Silicon Valley, OPPO Digital is continuously working on bringing new ideas and new products to customers. Over the past 8 years, OPPO has developed and released a series of award-winning universal DVD and Blu-ray players. But just as video has entered the Ultra HD era, OPPO Digital acknowledges audio is evolving with the rise of high-resolution music and a renewed interest in personal audio. Aiming at demanding customers in the personal audio space OPPO has announced the new PM-1 Planar Magnetic Headphone and HA-1 Headphone Amplifier. The PM-1's became available middle April and the HA-1 one month later.

audioXpress is deeply rooted in the R&D and DIY audio communities. So is Elektor, our sister publication that originated in Europe. Elektor International Media (EIM) group publishes Elektor, audioXpress, Voice Coil, the Loudspeaker Industry Sourcebook, and Circuit Cellar.

Jack said he started subscribing to audioXpress when he discovered that it was a continuation of the Audio Amateur publication. He said he was hoping to find back issues that may contain an upgrade article on the Adcom GFP-565 preamplifier.

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New England Audio Resource (N.E.A.R., which was originally called New England Audio Research) was founded in 1988 by Bill Kieltyka. Interestingly, the company purchased a lot of the transducer tooling from Rudy Bozak, and its line was always based, as with Bozak, on aluminum cone woofers and tweeters. (For a period of time, I designed the networks for the entire N.E.A.R. line of two-channel and home-theater speakers).

Antonio subscribed to audioXpress after being linked to it from Elektor, which he said he had been familiar with for a long time. At first, he said he just read the audioXpress articles. Then he said he realized there is a community of great folks, who are really into audio and acoustics innovation. Antonio said, “I thought that I may learn and have a lot of fun if I could be part of it.”

I was not really seeing audio products designed for a variety of applications with different approaches to record or play back music that would suit my needs. So in late 2009/2010, the former head engineer from Summit Audio and I started designing visionary gear. SBS designs makes my vision of US-made high-end designs with a left-field approach available to users.