The 1975 issue 2 edition of The Audio Amateur features high-performance circuit designs, definitive kit evaluations, and practical guides for the audiophile community. Here are the highlights to entice you to pick up this issue:
- A Variable Frequency Equalizer: Move beyond basic tone controls with this professional-grade three-section peaking equalizer. Featuring 12dB of boost or cut and adjustable frequency ranges, this project is ideal for fine-tuning home systems or integrating into a modular mixer.
- How to Found an Audio Group: Learn how to build a thriving community of local audiophiles with first-hand advice from the leaders of the Boston and New York Audio Societies. This article covers everything from initial organization and meeting logistics to finding the perfect "home" for your group.
- Kit Report: The Taming of Ampzilla: Get the definitive word on the legendary Great American Sound "super power" amplifier. Expert Walt Jung provides exhaustive bench tests and introduces critical modifications to the input stage and bias regulator to help you achieve true state-of-the-art fidelity from this 200W-per-channel beast.
- Speaker Evaluation: Ear or Machine? (Part 2): Roger H. Russell continues his investigation into the "elegant techniques and machines" used to measure loudspeaker performance. Discover how to account for room acoustics, interpret real-time analyzer data, and conduct more valid subjective listening tests.
- Audio Aids: This issue is packed with reader-submitted ingenuity, including a specialized XLR cable checker and a professional technique for "oven-baking" a durable, high-end finish onto your custom equipment panels.
- Op Amps for Audio: Active Filters (Part 2): Master the design of Infinite Gain Multiple Feedback (MFB) filters for precision signal management. This technical guide provides the equations and IC recommendations needed to build high-performance low-pass, high-pass, and bandpass active filters.
Table of Contents
- A Variable Frequency Equalizer: by Staff .......................................................................... 3
- How to Found an Audio Group: by James B. Brinton and Charles P. Repka ................. 8
- Kit Report: Taming Ampzilla with Walt Jung: by Walt Jung ............................................ 11
- Speaker Evaluation: Ear or Machine? Part 2: by Roger H. Russell .............................. 20
- Audio Aids: by readers Moffet, Miller, Anderton and Colbert ........................................ 26
- Op Amps for Audio: Active Filters, Part 2: by Walt Jung ................................................ 28
- Letters .................................................................................................................................... 38
- Classified ................................................................................................................................. 44
- Ad Index ................................................................................................................................. 44