The Magic of Tubes is Back with audioXpress May 2018 Glass Audio Special

The May edition of audioXpress continues to be a favorite among tube and audio electronics aficionados. For this Glass Audio Special issue, Menno van der Veen, details his fifth 300B-SE amplifier, Patrick Brunner discusses DIY Tube Amp Heat Management, and Gerhard Haas shares what he knows about output transformers for tube amplifiers. We interviewed Jason Stoddard, the heart and mind of Schiit Audio, and Richard Honeycutt compares Tubes, FET, and BJT circuits. Also in this edition, Andy Lewis looks at Back EMF in loudspeakers, and Ron Tipton finds a way to measure the high-frequency content of Master Quality Authenticated (MQA) recordings. Download your May issue now.

In this article, Richard Honeycutt provides a brief description of the main tube types used in audio applications, from triodes to tetrodes and pentodes, describing its uses, features and potential benefits. If you are looking for a quick reference reading about tubes that have been used in audio amplification this article is a great start. This article was originally published in audioXpress, May 2013 as part of the Hollow-State Electronics monthly column by Richard Honeycutt.

Now launched on crowdfunding platform Indiegogo, the PLASMA Pedal is an interesting innovation in an area where there's hardly been any for decades. The idea for the PLASMA comes from a young Latvian company, Gamechanger Audio, dedicated to infuse new ideas into the musician market. And the PLASMA is certainly new in the fact that instead of the traditional circuits, it sends continuous high-voltage discharges within a xenon-filled tube. In essence - playing a bolt of electricity!

Reedsburg, Wisconsin-based Sound Devices announced the recent acquisition of Audio Limited, the UK manufacturer and developer of high-performance wireless microphone systems. Audio Ltd., now a wholly-owned subsidiary of Sound Devices, will continue to operate out of its Watford, UK offices with Kishore Patel and Lee Stone continuing as managing director and technical director, respectively.

audioXpress February 2018 explores the progress being made by ORA Sound and GraphAudio, two pioneering companies with distinctly different approaches to the use of graphene based transducers. We explain why open reel analog tapes are coming back in force, the differences between Line Source and Point Source speakers, and how Dante Domain Manager is providing an integrated approach to media network management. All this and much more, now available!

This year we thought our readers would like to know which of the topics and stories published online in 2017 were the most popular for our community. We looked at the most-read articles of 2017 in audioXpress.com (which also includes selected articles from Voice Coil magazine), and we created this Top 10 list of news stories and online articles. Here are the results!

The MA252 Integrated Amplifier is the first ever hybrid integrated amplifier design from McIntosh. Unveiled early November 2017, the MA252 is now shipping. The amp brings the benefits of vacuum tube (valve) to its preamp stage, with solid-state technology on the output stage, all with a visually stunning, integrated package, taking retro design cues from the legendary McIntosh MC275 Vacuum Tube Amplifier.

Swedish microphone manufacturer Milab Microphones AB (Milab) has agreed with the owners of Pearl Mikrofonlaboratorium AB (Pearl) to acquire 100% of the shares in Pearl and consolidate Pearl’s operations and product portfolio into Milab. The two Swedish companies share the same history that goes back to 1941, but went separate ways almost 40 years ago.

Tubes or transistors? Whatever your prejudices, this article may make you change your mind about how you view hybrid designs. audioXpress featured this modular hybrid amplifier project in February 2001, which was referenced multiple times by other authors in many subsequent projects. The project features a shunted regulated push-pull (SRPP) stage design, using the ECC82/12AU7 tube combination, followed by a power stage, using two to eight complementary power MOSFETs in parallel.

Published in two separate parts in audioXpress October and November 2007, this hybrid amp design is a detailed and interesting project, frequently referenced by other DIY audio enthusiasts. We thought it was time to make it available online in its entirety, in the best possible quality. The article discusses the unity-gain, single-ended MOSFET output stage, the valve voltage amplification stage and wraps up with the power supplies, printed circuit boards, and construction.