JFETs: The New Frontier, Part 1

The basic circuits on which Erno Borbely based most of his projects are described in “JFETs: The New Frontiers, Part I and II,” published in Audio Electronics AE 5/99 and 6/99. Referring to these articles frequently, the author admits, these were the “building blocks” on which many - if not all - of his amplifiers are based. This article is the first part, as originally published in Audio Electronics, Vol. 5 1999.

Three audio experts discuss the role of distortion levels in what we hear. The debate was caused by an article titled “Amplifier Musicality - A Study of Amplifier Harmonic Distortion Spectrum Analysis” by Jean Hiraga, which originated comments by Jan Didden, Dennis Colin and a subsequent response by Jean Hiraga. The original article appeared in audioXpress March 2004 and the resulting conversation was published in audioXpress October 2005.

Here’s a simple, safe, inexpensive project for beginners and those who wish to “try tubes.” Meanwhile the project has been tried, tested, approved and improved, become one of the classic DIY audio projects from the author. This article was originally published in audioXpress magazine, November 2002.

Attention, all first-time (or wanna be) builders of single ended directly heated triode amps. This project’s for you. This is an easy to build, simple direct-coupled input/driver circuit that provides the proper drive voltage to the grid of the 211. A nice way to experiment with a single-ended (SE) triode amplifier.

Here’s a do-it-yourselfer’s dream in tube amp design: four operating modes, high quality, low cost, and low distortion. An article originally published by audioXpress in May 2007. A true versatile project which we think deserves to be shared.

With a little know-how and some basic parts, you can design a hybrid amplifier in fairly short order. This project combines the best attributes of both tube and transistor technologies.