AES British Section lectures - May 2007
Balanced Audio
Bill Whitlock, President and Chief Engineer Jensen Transformers Inc
www.jensentransformers.com
Although the subject has a "black art" reputation, this tutorial replaces myth and hype with insight and knowledge, revealing the true causes of system noise and earth loops. Although safety must be the top priority, some widely used "cures" are both illegal and deadly. While both balanced and unbalanced interfaces are vulnerable to noise coupling, the unbalanced interface is exquisitely so due to an intrinsic problem. Because balanced interfaces are widely misunderstood, their near-perfect noise rejection is severely degraded in most real-world systems. Some equipment has a built-in noise problem due to an innocent design error. A simple, no-test-equipment, troubleshooting method can pinpoint the location and cause of system noise. Signal-path earth isolators solve the fundamental noise coupling problems. Unbalanced to balanced connections, RF interference, and mains treatments such as technical power, balanced power, isolation transformers, and surge suppressors will also be discussed. The InGenius IC and a new BALANCED RCA connector will also be described.
Bill Whitlock has designed pro audio and video electronics and systems for over 30 years. In 1989, after seven years with EMI-Capitol Records, he became president of Jensen Transformers. He has become a recognized expert on system interfacing issues through his writing and teaching. His paper on balanced interfaces appears in the June 1995 AES Journal, which has become the most popular ever printed. Other writing includes regular columns in Sound & Video Contractor and Live Sound magazines, three chapters for Glen Ballou's 1500-page "Handbook for Sound Engineers," and numerous magazine articles and Jensen application notes. Since 1994, he has helped thousands unravel the mysteries of grounding and signal interfacing by teaching at trade shows, technical colleges, and professional organizations. Bill holds several patents including the InGeniusR balanced input circuit and the ExactPowerR waveform-correcting ac power voltage regulator. He is an active member of the Audio Engineering Society and a senior member of the Institute of Electrical and Electronic Engineers.
Lecture recording - mp3 format (27.4 MB)
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