The second issue of 1973 for The Audio Amateur (Issue 2/1973) is a masterclass in precision DIY engineering, featuring everything from radical tonearm designs to sophisticated noise reduction. Here are the highlights to entice your inner audio craftsman:
- A Dynamic Hiss Filter: Conquer the "shadowy" noise of SCA signals and old 78s without losing musical clarity . Jack Hazlehurst, Jr. presents a sophisticated "systems approach" to design, providing a circuit that intelligently opens and closes its bandwidth based on the program material to keep your music bright and the hiss at bay .
- A Do-It-Yourself Tonearm: Can a home-built tonearm outperform world-class commercial units? Legend Roger Sanders details how to build a precision, low-friction arm using model racing car bearings and a unique magnetic anti-skating system for less than $10 .
- IGOR: Washer for Dirty Discs: Eliminate surface noise and "discpan hands" with a high-power vacuum record cleaning machine . Kurt Wiley shows you how to repurpose a household compressor and laboratory flasks into a professional-grade cleaning system that pulls deep-seated grit out of your grooves in seconds .
- IC Op Amps for Audio: Master the foundations of modern solid-state circuitry . Audio pioneer Walt Jung demystifies the integrated circuit operational amplifier, teaching you how to achieve laboratory-grade performance and precision in your custom projects with a minimum of investment .
- Going Sound Fishing: Discover the "overwhelming superiority" of live recording . Professional recordist Gerry Turner provides a practical guide for the amateur enthusiast on finding local bands, selecting the best microphones, and the technical art of capturing a first-rate ensemble performance in its natural environment .
- Learning to Use Transistors: Part 13: Master the critical science of thermal stability in single-stage amplifiers . This installment explains the physics behind "thermal runaway" and provides the essential mathematics to design stable, high-performance circuits that stay reliable as they heat up .
- Audio Aids & Comfort: This issue is packed with reader-submitted ingenuity, including a sophisticated Multi-Dolby switching system, a DIY fix for flickering neon pilot lights, and modifications for adding extra speakers to the Heath AR-1500 .
- Technical Supplements: Deepen your engineering knowledge with specialized reports on Thyristor Supply calculations for power regulation and a detailed look at The Design Process for building electrically tunable low-pass filters .
Table of Contents
- A Dynamic Hiss Filter: by Jack H. Hazlehurst, Jr. ................................................................ 3
- A Do-It-Yourself Tonearm: by Roger R. Sanders ................................................................ 11
- IGOR: Washer for Dirty Discs: by Kurt M. Wiley ................................................................ 15
- Audio Aids & Comfort: by readers Furbush, Day, and Levin ............................................. 20
- Tapeniques: Going Sound Fishing: by Gerry L. Turner ..................................................... 26
- IC Op Amps for Audio: by Walt Jung .................................................................................. 28
- Learning to Use Transistors: Part 13: by C.N.G. Matthews ............................................... 32
- LETTERS ..................................................................................................................................... 34
- A Thyristor Supply (Technical Supplement) ........................................................................ 40
- The Design Process (Technical Supplement) ...................................................................... 41
- CLASSIFIED ................................................................................................................................ 45