Designing Audio Circuits and Systems

Bob Cordell is an electrical engineer who has been deeply involved in audio since his adventures with vacuum tube designs in his teen years. He is an equal-opportunity designer to this day, having built amplifiers and preamplifiers with vacuum tubes, bipolar transistors, JFETs and MOSFETs, and is a prolific designer of audio test equipment, including a high-performance THD analyzer and many purpose-built pieces of audio test gear. He has published numerous articles and papers on power amplifier design and distortion measurement in the popular press and in the Journal of the Audio Engineering Society. In 1983 he published a power amplifier design combining vertical power MOSFETs with error correction, achieving unprecedented distortion levels of less than 0.001% at 20 kHz. He previously published the book Designing Audio Power Amplifiers.

Bob is an avid DIY loudspeaker builder and has combined this endeavor with his electronic interests in the design of powered audiophile loudspeaker systems. He also consults in the audio and semiconductor industries and has presented audiophile listening and measurement workshops with his colleagues at the Rocky Mountain Audio Fest and the Home Entertainment Show. As an electrical engineer, Bob has worked at Bell Laboratories and other related telecommunications companies, where his work has included design of integrated circuits and fiber optic communications systems. Bob holds 17 patents and has presented numerous papers at the International Solid State Circuits Conference (ISSCC), the Convention of the Audio Engineering Society and other related professional meetings. Bob maintains an audiophile website at www.cordellaudio.com where diverse material on audio electronics, loudspeakers and instrumentation can be found.