Ein fünfjähriges Jubiläum
Elektor Special Audio 5, November 2011
Foreword
This is our fifth Audio Special, a milestone worth celebrating. Over the past five years, we have presented hundreds of pages of exceptional construction proposals, unique in their kind and unlikely to be found in the commercial realm. These contributions originated from suggestions by dedicated amateurs, some working at a semi-professional level, and from professional circuit developers in the industry who have taken the time to nurture their Hi-Fi passion alongside their professional activities. The editorial team and Elektor would like to express their sincere gratitude for this.
In the tube amplifier section at the front of the magazine, we have compiled a mix of projects for various applications. This ranges from a living-room-suitable guitar amplifier that, despite its modest one watt of amplification power, delivers the full, unpretentious tube sound. It continues with an amplifier with a crossover for activating Hi-Fi speakers, a triode amplifier with a substantial KR300B, and a preamplifier built with output tubes. The tube section is rounded off by a fundamental article on the topic of the output transformer, the very component without which hardly any Hi-Fi tube amplifier can do without, regardless of its design.
In the semiconductor section, a professional circuit developer describes the development steps of a symmetrical preamplifier uncompromisingly trimmed for sound quality, which not only optimally matches the Extreme-A output stage from the penultimate issue in terms of its technical data.
The highly practical electronics that turn a pushbutton switch into a power switch for an amplifier falls more into the 'magic box' category.
This time, the focus is on more compact loudspeaker designs, with the popular full-range drivers being particularly well represented.
We wish you much enjoyment in reading and building!
Your Team from Elektor International Media
Rolf Hähle, Editor-in-Chief Audio 5
Contents
Tube Technology
- 4 Classic Three Preamplifier: Push-pull circuit with cathode follower.
- 10 Line Preamplifier with 6C33: Amplification with a power tube?
- 16 The Conductor: A preamplifier with active crossover.
- 22 Single-Ended Stereo Power Amplifier KR300B: The exceptional 300B.
- 28 1 Watt Living Room Guitar Amplifier: Tube sound even at low volumes.
- 32 iGoliath Single-Ended 211: Single-ended triode amplifier with 211.
- 38 How Does an Output Transformer Work?
Loudspeakers
- 56 Morel Elite 420 by Eltim Audio: Small active two-way combination with DSP.
- 61 All Black by Henkjan Olthuis: Full-range driver CSS EL70 with transmission line.
- 64 HATT-SE Mk. II: A compact 2-way monitor with Seas Excel chassis.
- 68 Silverado by Sander Sassen: 2-way D'Appolito with Seas L12 and 27TB.
- 72 Legno TL by Monacor: A FAST system with TL subwoofer, fully active with DSP and Class-D.
- 80 Wall-i by ASE: The picture speaker for personal design.
- 84 SAK-PC with Peerless/Vifa by ASE: Active or passive, PC-optimized either way.
- 87 Mini-Wall by Blue Planet Acoustic: On the wall or on the table – both work well with the small point sound source.
Semiconductor Technology
- 46 Prelude, the Preamplifier: Uncompromisingly purist design.
- 52 Click On / Click Off Switch: The electronics for appropriate switching.
- 89 Market / News
- 90 Advertiser Index
- 51 Imprint
