The 1976 issue 4 of The Audio Amateur concludes the magazine's seventh year with a 64-page edition featuring sophisticated IC applications, classic tube modifications, and essential testing guides. Here are the highlights of this issue:
- Compandor Power with the 570/571 IC: Unlock the potential of the new Signetics monolithic compandor chips. Audio legend Walt Jung and Craig Todd provide a deep dive into these versatile devices, offering ready-to-use circuits for professional-grade noise reduction, voltage-controlled faders, and high-performance squelch systems.
- Modify Your Heath IM Distortion Analyzer: Don't retire your trusty tube-type IM-48 just yet. Frederick Gloeckler reveals how to slash residual distortion from 0.1% to near-professional levels through clever power supply filtering and filter modifications, ensuring your vintage gear can test modern state-of-the-art equipment.
- Modernizing the Dyna Stereo 70: Give the world's most popular tube amplifier a "modest gilding." H.L. Eisenson details an affordable, effective modification focusing on power supply and bias stability to achieve accurate performance that rivals expensive boutique gear.
- Master the Art of Tape Set-up: Craig Stark continues his masterclass on making your recorder "feel better and work better." Part 2 focuses on the critical electronic adjustments—including bias, record equalization, and VU meter calibration—needed for peak fidelity.
- Reach for the Rafters with a 20-Foot Mic Stand: Tired of poor mic placement at live recordings? Learn how to build a rugged, portable, 20-foot tall microphone stand for around $20 using stainless steel conduit. It’s the perfect solution for capturing the perfect ambiance in churches and concert halls.
- Professional Testing on a Budget: Is the Heath IO-4550 the high-performance tool your workbench is missing? Our in-depth kit report puts this 10MHz dual-trace, triggered-sweep oscilloscope to the test to see if it delivers the precision required for serious audio work.
- Discover the Best of Europe with the Euro-Disc Gazette: Bound into this issue is the premier of a new feature offering reprints of elite record reviews from across the pond. Find the finest European recordings and learn how to have them shipped directly to your listening room.
- Audio Aids: A treasure trove of reader-submitted ingenuity, from DIY wire-wrapping tools for prototyping to essential performance hacks for AR turntables and Heath TV sets.
Table of Contents
- Operation and Uses for the 570/571 IC compandor chip: by Walt Jung and Craig Todd ... 3
- Modify your Heath tube-type IM distortion analyzer: by Frederick M. Gloeckler, Jr. ... 9
- Dyna's Stereo 70: a simple modification: by H. L. Eisenson ... 13
- A-Z Tape recorder set-up--Part 2: by Craig L. Stark ... 16
- A tall, portable microphone stand: by Alan S. Douglas ... 26
- Audio Aids: by readers Berglas, Gloeckler, Branam, and Carlstrom ... 28
- Euro-Disc Gazette ... 31
- Kit Report: Heath's IO-4550 Oscilloscope: by Fred M. Gloeckler, Jr. ... 38
- LETTERS ... 50
- CORRECTIONS ... 50
- JUST LOOKING ... 57
- CLASSIFIED ... 59
- AD INDEX ... 59