Author

Cordell Bob

Cordell Bob

Bob Cordell 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 with vacuum tubes, bipolar transistors and MOSFETs. Bob is also a prolific designer of audio test equipment, including a high-performance THD analyzer and many purpose-built pieces of audio 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. Bob is a member of the JAES Review Board. He was the first to publish and demonstrate a power amplifier design combining vertical power MOSFETs with error correction, achieving unprecedented distortion levels of less than 0.001% at 20 kHz, full power in 1983. Bob is also an avid DIY loudspeaker builder, and has combined this endeavor with his electronic interests in the design of powered audiophile loudspeaker systems. Bob and some colleagues have presented audiophile listening and measurement workshops at The Rocky Mountain Audio Fest and the Home Entertainment Show.

As an Electrical Engineer, he has worked at Bell Laboratories and other telecommunications companies, where his designs have included integrated circuits and fiber optic communications systems. Bob maintains an audiophile website at http://www.cordellaudio.com where diverse material on audio electronics, loudspeakers and instrumentation can be found.

Written articles
VinylTrak – A full-featured MM/MC phono preamp

After spending many years to write an encyclopedic tome on audio power amplifier design, Bob Cordell decided to turn his considerable talent to the design of a phono preamplifier. Strictly solid...

The Distortion Magnifier

Audio equipment has become so transparent that it taxes the resolving power of all but the most expensive distortion analyzers. Bob Cordell developed the Distortion Magnifier (DM) as an add-on to...

The C70 KT-88 Vacuum Tube Stereo Amplifier

In The C70 KT-88 Vacuum Tube Stereo Amplifier, Bob Cordell shows he is equally well versed in tube technology as he is in solid state design. This amplifier uses solid state devices in the...

TPC and TMC Feedback Compensation for Power Amplifiers

Bob Cordell explored power amp compensation techniques that allow the designer to employ more feedback loop gain at higher frequencies, improving amplifier linearity at higher frequencies. Two-...

Book Review -The LTspice Simulator - Manual, Methods and Applications, Gilles Brocard - Bob Cordell

Bob Cordell is an experienced user of the free Spice simulator from Linear Technology, LTspice. Therefore, Bob eagerly anticipated reading this heavy volume, and wished the book had been available...