Capacitor Distortion

On the same note, a PowerPoint from Audio Precision:

By Bruce Hofer, Chairman & Co-Founder, Audio Precision

Hello Kevin,

Last month I discussed some of the sources of non-linear distortion that resistors can introduce in analog circuits. I also mentioned that more information would be included in a tutorial I was scheduled to present at the Rome AES Convention that was held recently on May 3–7. A copy of my slides may be downloaded from the link below:

Download Designing for Ultra-Low THD+N in Analog Circuits

http://app.cooleremail.com/c.pl?5ce6ea18a3d849ca34f9f93738b222a11d2ac5fc64c26ad7

In a major departure from past conventions, the AES convention in Rome this year was held in a special business meeting venue that was not an exhibition hall, or associated with a major hotel. “Exhibits” were replaced by small tables manned by “Sponsors” located throughout the hallways between the various lecture rooms. Audio Precision was one of perhaps only 20 such sponsors present this time. While the technical program of European AES conventions remains strong, exhibits have been struggling to find the proper tradeoff between business opportunity and cost. Perhaps this newer, less formal form of exhibiting will encourage increased participation in the future.

As always Rome offers some of the best sights (and food) in all of Europe. While sipping a grappa after a particularly good dinner one night, I caught myself wondering if the ancient Romans had any concept of distortion…

Bruce

Continuing on the same note:
Do a search for these old Cyril Bateman Articles. The URL's keep moving about.

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Cyril Bateman Articles
Electronics World Magazine

Capacitor Distortion: Part 1 _ _ _ _ Cyril Bateman _ July 2002 _ p12
Capacitor Distortion: Part 2 _ _ _ _ Cyril Bateman _ Sept 2002 _ p16
Capacitor Distortion: Part 3 _ _ _ _ Cyril Bateman _ Oct 2002 _ p12
Capacitor Distortion: Part 4 _ _ _ _ Cyril Bateman _ Nov 2002 _ p40
Capacitor Distortion: Part 5 _ _ _ _ Cyril Bateman _ Dec 2002 _ p44
Capacitor Distortion: Part 6 _ _ _ _ Cyril Bateman _ Jan 2003 _ p44
Capacitor Sounds II: Part 1
Real-Time Hardware _ _ _ _ _ _ _ Cyril Bateman July 2003 p36
Distortion v Time v Bias _ _ _ _ _ Cyril Bateman _ Aug 2003 _ p46
Capacitor Sounds II: Part 3
Distortion Meter _ _ _ _ _ _ _ _ _ Cyril Bateman _ Sept 2003 _ p46
Capacitor and Amplifier Distortions _ Cyril Bateman _ Nov 2003 _ p44

Capacitor distortion is not exactly a new discovery, and everything depends on what kind of capacitor, and the ratio of AC to DC voltage across it. Ceramics of the wrong sort can look like something much more complex than any capacitor. Ditto electrolytics, including bipolars in crossovers.

Ditto things like carbon resistors, which have a very surprising coefficient of resistance vs. voltage if you get beyond small-signal voltages. I've seen quite some surprising kinds of distortion from resistors running with 200 vrms. Replacing with metal film dropped distortion from -40dB to -110dB. Ooops.