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Tag: audio amplifier
Hifisonix kx2 Class A Current Feedback Amplifier
The 15W RMS (28W peak class A) kx2-Amplifier offers outstanding noise and distortion performance and is specifically designed for driving high efficiency speakers in average to large listening spaces but also performs well driving more normal efficiency speakers in restricted listening spaces. Please note the kx2-Amplifier PCBs are supplied by Jim’s Audio. You can buy…
Hifisonix sx-Amplifier: A 15 W Class A Current Feedback Amplifier
Originally published in August 2012. Click here to order a set of DS THP PCBs for the sx-Amplifier from Jim’s Audio About 150 sx-Amplifier PCB sets have been sold, with most of those going on to be built. As you can read about in the PDF below, my class A journey started off after listening…
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 power amplifiers and preamplifiers. I first started out in audio around 1975 or 76 as 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…
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…
Review of Bob Cordell’s Book ‘Designing Audio Power Amplifiers’
‘Designing Audio Power Amplifiers’ by Bob Cordell – Reviewed by Andrew C. Russell in 2011 Bob Cordell (on the right) pictured with Jan Didden, publisher of ‘Linear Audio’ After a 15 year hiatus from electronics, I returned in 2005 to linear design not as a professional but as a hobbyist. Earlier in my career, I…
CFA Diamond Buffer IPS: Does it Operate in Class B or class A?
There is a persistent assertion by small group of amplifier design practitioners that the diamond buffer input stage of CFA audio amplifier operates in class B (or AB) mode wherein there is a hard ‘handover’ between each half of the diamond buffer input stage as the input signal passes through 0V. The most recent claim…