All items in category Project Articles

Build a Sound Level Meter and Spectrum Analyzer

June 3, 2015 by Ron Tipton

Build a Sound Level Meter and Spectrum Analyzer

Ron Tipton explains how he built his sound level meter and spectrum analyzer, the Model 527, around a Velleman Audio Analyzer kit (K8098). This is a barebones kit with no enclosure or power supply, but for the price, it is very versatile. Originally published in audioxpress, December 2013.

Build a Low-Voltage Tube Hybrid Headphone/Line Amp

May 21, 2015 by Pete Millett

Build a Low-Voltage Tube Hybrid Headphone/Line Amp

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.

JBL L300 Modification

May 13, 2015 by Nelson Pass

JBL L300 Modification

In this much sought after modification project, Nelson Pass rekindles his desire for the JBL L300 Summit loudspeakers and completes a renovation. As he explains, “it is not a trivial task to improve on original JBL design." "I think I’ve managed to respect the JBL legacy while tweaking the sound to reflect the tastes of the 21st century.” Article originally published in audioXpress, January 2012.

A Low-Mu Triode Preamp

April 29, 2015 by Pete Millett

A Low-Mu Triode Preamp

In this article, originally published in audioXpress, February 2004, the author describes how to achieve low distortion from power triodes. As he explains, his preamp is “a little different from most, using low-mu power triodes to get good performance with only one amplifier stage, and no negative feedback. This achieves the modest gain required along with very low output impedance.”

A 211 SE Triode Amp

March 30, 2015 by Nick Soudas

A 211 SE Triode Amp

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.

The SPP Amplifier

March 18, 2015 by Helmut Otte

The SPP Amplifier

Here’s a long-forgotten, but still high-quality, power amp design that’s easy to build, requiring no esoteric tubes or parts. Originally published by audioXpress on May, 2003, this project was submitted by Helmut Otte, who worked at the University Of Applied Sciences Hamburg, after having started is electronics career at Philips Service department in Germany.

A Versatile Line Amp for Preamp, Headphone, and Power Use

February 27, 2015 by Joseph Norwood Still

A Versatile Line Amp for Preamp, Headphone, and Power Use

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.

Extend the useful life of those precious tubes: use a Tube Amplifier High-Voltage Delay

February 25, 2015 by Jan Didden

Extend the useful life of those precious tubes: use a Tube Amplifier High-Voltage Delay

Tube life can be extended if you delay the application of high voltage until after the heaters have warmed up and current can flow. This little module does just that: depending on the setting of a jumper, it delays the high-voltage for 40 or 60 seconds after the amplifier is switched on. And the module is available as a kit. This article was originally published in audioXpress, February 2014.

FREE DOWNLOAD

The Willow Pre-amp: A high slew-rate JFET amplifier

January 17, 2015 by Robert Nance Dee

The Willow Pre-amp: A high slew-rate JFET amplifier

This project, originally published by audioXpress in December 2011, has been the topic of much discussion, updates and follow-up projects, so much so that we decided to make it available online. As the author, Robert Nance Dee, explains, “…the people who have listened to this amp can hear the difference. I built it as a companion to my 5002 power amp, both using the HA5002 buffer.”

An inexpensive, easy-to-build sound level control

December 26, 2014 by J.R. Laughlin

An inexpensive, easy-to-build sound level control

This circuit contains an audio amplifier capable of driving a speaker with circuitry that automatically maintains the same relative maximum output regardless of extreme levels that are occurring at the input. It does not “compress” the peaks, but simply “turns down the volume” as you would do with your volume control

«
1
2
3
4
5
6
7
8
9
10
11
»