Looks like an exciting publication.
The Arch Nemesis Nelson Pass
Nelson Pass' designs invariably give excellent sound quality from a simple, class-A based design. The large idle dissipation in such designs has always been accepted as worthwhile for the performance. With the Arch Nemesis, Nelson pays tribute to the classical single-ended triode amp, but replaces vacuum state with silicon carbide, delivering another great design that is simple and high-quality, with good efficiency.
--------------------------------------------------------------------------------
From the editors desk Jan Didden
Why would anyone in his right mind start an audio publication in this time and age? Well, its like this....
--------------------------------------------------------------------------------
Book review Andy Bryner
Andy reviews Douglas Selfs' latest book, "Small-signal Audio Design", and likes what he reads.
--------------------------------------------------------------------------------
Taming the split-load inverter Stuart Yaniger
Despite its extreme simplicity, the split load phase inverter is capable of stellar performance. It is also a highly misunderstood circuit, and these misunderstandings have led to some less-than-optimal design. In this article, we review the basics of its operation, derive the basic equations, and outline its advantages and disadvantages. Several versions of the circuit are built and characterized, including some dubious variations often recommended to "fix" non-existent (but commonly believed) problems. Output impedance, load tolerance, and distortion are examined.
--------------------------------------------------------------------------------
Project 21, part I: the satellites Jean-Claude Gaertner
Project 21 is an extensive project consisting of a satellite two-way with a bass enclosure. All drivers are driven actively through a DSP-based crossover. Four-channel level controls are used at each speaker location, which are RF-remote controlled. This is a joint project from Jean-Claude Gaertner and Jan Didden. In Part I Jean-Claude discusses the design considerations and prototype measurements of the satellites. He shows extensive measurement results on the chosen drivers as well as the completed satellite, response simulations and satellite construction details.
--------------------------------------------------------------------------------
The Distortion Magnifier Bob Cordell
Audio equipment has become so transparent that it taxes the resolving power of all but the most expensive distortion analyzers. Bob Cordell developed the Distortion Magnifier (DM) as an add-on to a distortion analyzer, to increase the resolution. By increasing the distortion fraction in the measurement signal, the DM increases the resolving power of an analyzer by 20 or 40dB. Useable for a stand-alone distortion analyzer as well as with a PC-soundcard and software-based set-up. For availability of a PCB and some specific parts contact www.pilghamaudio.com
--------------------------------------------------------------------------------
Inclusive Compensation and Ultra-Low Distortion Power Amplfiers Douglas Self
Two things define the distortion performance of a power amplifier; the open-loop linearity of the circuitry, and the amount of negative feedback that can be safely applied. The latter is determined by the compensation scheme used. The almost-universal Miller dominant-pole method gives excellent and reliable results, but can be significantly improved upon by techniques such as two-pole compensation which allow more feedback at audio frequencies. Inclusive compensation promises even better performance, but as normally conceived it is not workably stable. Here Douglas shows how to make it work. The results are dramatic, and the extra cost is trivial.
--------------------------------------------------------------------------------
A New Low-Noise Circuit Approach for Pentodes Frank Blöhbaum
In the tube world, it is taken for granted that if you want a low noise amplifier you don't use a penthode; penthodes have higher noise and more 3rd harmonic distortions than a triode.
But Frank Blöhbaum doesn't take things for grated. He researched this common wisdom and found out that penthodes can be used in low-noise applications with advantage, and shows some innovative circuitry to do just that. The article also contains an extensive comparision between different tubes on noise and distortion performance.
--------------------------------------------------------------------------------
The Mini-Simplex Ari Polisois
Ari has been publishing his DC-coupled, Modulating Bias design as the Simplex amplifier. In this article, he combines this technology with the Split Core Stereo Common Circuit transformer design he has developed, to come up with a very simple yet well-sounding amplifier build around a 6C33 and 6SN7GT. The mini-simplex delivers some 6W per channel with better efficiency than the Simplex. This new design is easy to build and is ideal to drive high efficiency (wide band) speakers.
--------------------------------------------------------------------------------
The IC notebook Ed Simon
If, like Ed Simon, you have more different IC's than you can keep track off, you'll like his tip on how to use a notebook to easily classify and find IC's. The system is easy to set up and can even be used with transistors and diodes.
--------------------------------------------------------------------------------
STEREO - From live to recorded and reproduced - What does it take? Siegfried Linkwitz
The problematic with stereo sound reproduction starts already at the recording end of the signal chain. The sound transmission from the live event to its reproduction in a small room must be treated as a system if realism and believeability are the goal. Dr. Linkwitz discusses the whole chain, touching on subjects like binaural recording and playback, microphone techniques, perception of real and phanton sources, diffraction, directivity, distortion, crossovers, the listening room, the loudspeakers and much more. For each area he highlights the significant factors and how to optimize them. A must-read if you want realism and believeability in your own listening room.
--------------------------------------------------------------------------------
Down the Rabbit Hole - Adventures in the Land of Phonostages Joachim Gerhard
When prolific designer Joachim Gerhard puts his teeth into something, he will get to the bottom. His Flexible Phono Stage (FPS) is a model of purpuse-driven design. Touting the lowest noise in any MC-preamplifier, the FPS uses a mixture of JFETs, opamps and bipolars in a fully balanced design (including the RIAA part). It can be configured for low or high input Z to match your cartridge. Performance is exemplary with very accurate RIAA correction, extremenly low noise and very low distortion. A preamp that will bring out the best on your vinyl. For availability of PCB's, parts and (half) kits contact www.pilghamaudio.com
--------------------------------------------------------------------------------
Which was your first single? Rene Wouda
Trading off the excitement of the sixties against the user friendliness of the 21st century.
--------------------------------------------------------------------------------
Book sneak preview Jan Didden
Bob Cordell's magnus opus 'Audio Power Amplifier Design' was just being released when Linear Audio Volume 0 went to press. But we'll have a review in the next issue for sure!
--------------------------------------------------------------------------------
Low frequencies in rooms Tom Nousaine
Tom Nousaine exposes some myths about low frequency reproduction in home listening rooms. He cites manufacturer surveys about customer listening rooms with the surprising conclusion that listening rooms tend to be quite similar as opposed to the idea that all rooms are different. He then provides measured results that suggest that the modern great room is a much better listening space relative to low frequency performance than often assumed. His conclusion is that room modes are important to provide the low frequency energy for listening and that judicious equalization and damping is often counterproductive.
--------------------------------------------------------------------------------
On the leakage inductance in audio transformers Pierre Touzelet
Leakage inductance is caused by that part of the primary flux that doesn't make it to the secondary. That, and the stray capacitance across the primary, limit the high-frequency performance of the transformer. Using a clever combination of split and overlapping windings, this can be optimized, but what is the best combination for a particular transformer?
Pierre Touzelet has analyzed the situation. This article is heavy on math but the conclusions point to a set of rules that are surprisingly simple.
--------------------------------------------------------------------------------
Home page is http://www.linearaudio.net/
The Arch Nemesis Nelson Pass
Nelson Pass' designs invariably give excellent sound quality from a simple, class-A based design. The large idle dissipation in such designs has always been accepted as worthwhile for the performance. With the Arch Nemesis, Nelson pays tribute to the classical single-ended triode amp, but replaces vacuum state with silicon carbide, delivering another great design that is simple and high-quality, with good efficiency.
--------------------------------------------------------------------------------
From the editors desk Jan Didden
Why would anyone in his right mind start an audio publication in this time and age? Well, its like this....
--------------------------------------------------------------------------------
Book review Andy Bryner
Andy reviews Douglas Selfs' latest book, "Small-signal Audio Design", and likes what he reads.
--------------------------------------------------------------------------------
Taming the split-load inverter Stuart Yaniger
Despite its extreme simplicity, the split load phase inverter is capable of stellar performance. It is also a highly misunderstood circuit, and these misunderstandings have led to some less-than-optimal design. In this article, we review the basics of its operation, derive the basic equations, and outline its advantages and disadvantages. Several versions of the circuit are built and characterized, including some dubious variations often recommended to "fix" non-existent (but commonly believed) problems. Output impedance, load tolerance, and distortion are examined.
--------------------------------------------------------------------------------
Project 21, part I: the satellites Jean-Claude Gaertner
Project 21 is an extensive project consisting of a satellite two-way with a bass enclosure. All drivers are driven actively through a DSP-based crossover. Four-channel level controls are used at each speaker location, which are RF-remote controlled. This is a joint project from Jean-Claude Gaertner and Jan Didden. In Part I Jean-Claude discusses the design considerations and prototype measurements of the satellites. He shows extensive measurement results on the chosen drivers as well as the completed satellite, response simulations and satellite construction details.
--------------------------------------------------------------------------------
The Distortion Magnifier Bob Cordell
Audio equipment has become so transparent that it taxes the resolving power of all but the most expensive distortion analyzers. Bob Cordell developed the Distortion Magnifier (DM) as an add-on to a distortion analyzer, to increase the resolution. By increasing the distortion fraction in the measurement signal, the DM increases the resolving power of an analyzer by 20 or 40dB. Useable for a stand-alone distortion analyzer as well as with a PC-soundcard and software-based set-up. For availability of a PCB and some specific parts contact www.pilghamaudio.com
--------------------------------------------------------------------------------
Inclusive Compensation and Ultra-Low Distortion Power Amplfiers Douglas Self
Two things define the distortion performance of a power amplifier; the open-loop linearity of the circuitry, and the amount of negative feedback that can be safely applied. The latter is determined by the compensation scheme used. The almost-universal Miller dominant-pole method gives excellent and reliable results, but can be significantly improved upon by techniques such as two-pole compensation which allow more feedback at audio frequencies. Inclusive compensation promises even better performance, but as normally conceived it is not workably stable. Here Douglas shows how to make it work. The results are dramatic, and the extra cost is trivial.
--------------------------------------------------------------------------------
A New Low-Noise Circuit Approach for Pentodes Frank Blöhbaum
In the tube world, it is taken for granted that if you want a low noise amplifier you don't use a penthode; penthodes have higher noise and more 3rd harmonic distortions than a triode.
But Frank Blöhbaum doesn't take things for grated. He researched this common wisdom and found out that penthodes can be used in low-noise applications with advantage, and shows some innovative circuitry to do just that. The article also contains an extensive comparision between different tubes on noise and distortion performance.
--------------------------------------------------------------------------------
The Mini-Simplex Ari Polisois
Ari has been publishing his DC-coupled, Modulating Bias design as the Simplex amplifier. In this article, he combines this technology with the Split Core Stereo Common Circuit transformer design he has developed, to come up with a very simple yet well-sounding amplifier build around a 6C33 and 6SN7GT. The mini-simplex delivers some 6W per channel with better efficiency than the Simplex. This new design is easy to build and is ideal to drive high efficiency (wide band) speakers.
--------------------------------------------------------------------------------
The IC notebook Ed Simon
If, like Ed Simon, you have more different IC's than you can keep track off, you'll like his tip on how to use a notebook to easily classify and find IC's. The system is easy to set up and can even be used with transistors and diodes.
--------------------------------------------------------------------------------
STEREO - From live to recorded and reproduced - What does it take? Siegfried Linkwitz
The problematic with stereo sound reproduction starts already at the recording end of the signal chain. The sound transmission from the live event to its reproduction in a small room must be treated as a system if realism and believeability are the goal. Dr. Linkwitz discusses the whole chain, touching on subjects like binaural recording and playback, microphone techniques, perception of real and phanton sources, diffraction, directivity, distortion, crossovers, the listening room, the loudspeakers and much more. For each area he highlights the significant factors and how to optimize them. A must-read if you want realism and believeability in your own listening room.
--------------------------------------------------------------------------------
Down the Rabbit Hole - Adventures in the Land of Phonostages Joachim Gerhard
When prolific designer Joachim Gerhard puts his teeth into something, he will get to the bottom. His Flexible Phono Stage (FPS) is a model of purpuse-driven design. Touting the lowest noise in any MC-preamplifier, the FPS uses a mixture of JFETs, opamps and bipolars in a fully balanced design (including the RIAA part). It can be configured for low or high input Z to match your cartridge. Performance is exemplary with very accurate RIAA correction, extremenly low noise and very low distortion. A preamp that will bring out the best on your vinyl. For availability of PCB's, parts and (half) kits contact www.pilghamaudio.com
--------------------------------------------------------------------------------
Which was your first single? Rene Wouda
Trading off the excitement of the sixties against the user friendliness of the 21st century.
--------------------------------------------------------------------------------
Book sneak preview Jan Didden
Bob Cordell's magnus opus 'Audio Power Amplifier Design' was just being released when Linear Audio Volume 0 went to press. But we'll have a review in the next issue for sure!
--------------------------------------------------------------------------------
Low frequencies in rooms Tom Nousaine
Tom Nousaine exposes some myths about low frequency reproduction in home listening rooms. He cites manufacturer surveys about customer listening rooms with the surprising conclusion that listening rooms tend to be quite similar as opposed to the idea that all rooms are different. He then provides measured results that suggest that the modern great room is a much better listening space relative to low frequency performance than often assumed. His conclusion is that room modes are important to provide the low frequency energy for listening and that judicious equalization and damping is often counterproductive.
--------------------------------------------------------------------------------
On the leakage inductance in audio transformers Pierre Touzelet
Leakage inductance is caused by that part of the primary flux that doesn't make it to the secondary. That, and the stray capacitance across the primary, limit the high-frequency performance of the transformer. Using a clever combination of split and overlapping windings, this can be optimized, but what is the best combination for a particular transformer?
Pierre Touzelet has analyzed the situation. This article is heavy on math but the conclusions point to a set of rules that are surprisingly simple.
--------------------------------------------------------------------------------
Home page is http://www.linearaudio.net/
