Ground Loops
Updated with new material 7th January 2019 This set of c. 70 slides is the culmination of my experience over a period of about 25 years building numerous power amplifiers and preamplifiers. I first started out in audio around 1975 or 76 a teenager. Some of my creations were reasonably quiet – through pure luck […]
How to wire-up a Dual Mono Bloc Amplifier
A few people have asked about wiring up a dual mono amp aka dual mono bloc. In a dual mono bloc there are separate power supplies and lots of opportunity for cross channel ground loops and ordinary ‘classic’ ground loops as well. This wiring scheme addresses the situation were unbalanced connections between the source equipment […]
Amplifier History: The JBL SA-600
The beautifully styled JBL SA-600 amplifier was launched by the James B. Lansing company in 1966, and Bart Locanthi (the designer) wrote the technical article linked to at the bottom of this write-up in January 1967. I’ve included this in the hifisonix power amplifier library because it is one of the earliest – if not […]
CFA vs. VFA: A Short Primer For the Uninitiated
This article was written in 2014 in response to what can only be described as a vitriolic debate as to what constituted a CFA on diyAudio.com. At the time, many of the participants were struggling to grasp the fundamental differences between VFA’s and CFA’s, and even how to tell them apart. So, this document is […]
Douglas Self’s 8 Distortions and a Few More
(pictured above is the hifisonix 180 Watt per channel e-Amp) No one had codified all the major audio amplifier distortion mechanisms until Douglas Self published the first edition of his ‘Audio Power Amplifier Design Handbook’ or APAD’ as it has become known, in 1996. He used a standard Lin* topology amplifier and then proceeded to […]
Some Ideas on Temperature Compensation for Audio Amplifier EF Triples
Temperature compensating an EF3 audio power amplifier output stage is not a trifling task. There are 6 Vbe junctions, running at 3 different current densities, different temperatures and neither is the thermal performance of the heatsink assembly characterized In most DIY cases. This makes deploying a conventional 2 transistor Vbe spreader (or Vbe multiplier as […]