A Double-Ended Two-Channel Amp

Following the publication of its original SE 6C33C amplifier in audioXpress July 2004, Ari Polisois returned with more information on how to further simplify the whole construction and reduce the costs. The results, as the author describes, "combine the advantage(s) of the push-pull (mainly power) to the wonderful character of the SE: sensitivity, smoothness, simplicity, and warmth (due to the 2nd harmonic content, easily tolerated by our ears, as against the third, fifth, seventh, and so on harmonics produced by the push-pull)." This article was originally published in audioXpress, February 2008.

The 150-year-old Western Electric will reintroduce its flagship product to market, the famous 300B electron tube. In time for its 80th anniversary, the 300B is returning to production this year, and the Rossville-based company announced they will restart the manufacturing in a brand new facility. Charles Whitener, Western Electric CEO, also confirmed the company will unveil a new single-ended amplifier called the 91E, as an homage to its famous predecessor the 91A, first introduced in 1936.

Previewed in 2016, and originally scheduled for Spring 2017, Dynaco (a division of Radial Engineering Ltd.) announced the ST-70 Series 3 tube amplifier is now shipping. Since acquiring the legendary Hafler and Dynaco brands in 2014, Radial Engineering has been carefully working on the Dynaco ST-70 Series 3 tube amplifier, in an effort to create a truly worthy successor of one of the most successful tube amplifiers of all time. The result is finally available!

UK audio brand Q Acoustics recently opened a direct-to-consumer webstore in the US and now announced a new range of hi-fi speakers with the mission of making genuine premium design products affordable to a mainstream audience. The new 3000i speaker series consists of the 3050i ($799) large floorstander, the compact 3010i ($249) and the mid-sized 3020i ($299). All incorporate technology originally designed for Q Acoustics flagship speaker, Concept 500 ($6K), sold at accessible price points.

This article from respected author Ari Polisois deals with a single-ended amplifier with enough power to drive even the most difficult speaker systems - delivering 50W per channel. This is a project that quickly became the focus in lots of tube-oriented forums and has inspired long threads and many iterations, including further articles published in audioXpress from the author himself. This article was published in audioXpress, July 2004.

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.

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.

Celestion announced a new way for users to acquire and build upon their library of Impulse Responses, the company’s authentic digitally downloadable speaker tones. The new Pick & Mix option, which is available in combinations of either 3 or 5 cabinets from the company’s full range of IRs, offers complete flexibility in the way users can choose to build their personal IR library at a significant savings compared to purchasing individual IRs.

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!

A popular hybrid amp design available for headphone use, this single-ended (SE) pure Class-A amplifier is capable of driving headphones between 32 and 600Ω, and was derived from an original tube/MOSFET line amplifier project, published by Erno Borbely in Glass Audio (1/98). Originally published in audioXpress in April 2005, this project was meanwhile extensively discussed in multiple DIY audio forums all over the world and is probably one of the most tested of Erno Borbely's designs, with multiple iterations frequently published on blogs and other publications.