Modern Op-Amp Distortion Tests: Part 2 — A Few More BJT Types and JFET Devices

Many new op-amp types have appeared in the last decade, and Douglas Self thought it was time to evaluate those for distortion performance. In Part 1 of his article, he measured BJT-input devices using a similar protocol for five different loads and testing for basic op-amp distortion in favorable circumstances. In this second article, the measurement of BJT types is concluded, and he moves the JFET types to the test bench.

Douglas Self has been using a tried-and-true palette of op-amps in his designs. Because many new types have appeared in the last decade, he thought it was high time to evaluate those for distortion performance. In Part 1 of this article, he examines BJT-input devices using a similar protocol for five different loads and testing for basic op-amp distortion in favorable circumstances. FET input op-amps are investigated in Part 2.

This November 2024 issue of audioXpress explores perspectives on signal processing, and sound reproduction. Read a review of the PSI Audio AVAA C214 digital active bass absorber, learn about the exciting possibilities of Audioscenic's Amphi Technology and how to explore the Boundaries of Active Noise Cancellation. J. Martins interviews Andreas Ehret from Dolby Laboratories. Expanding on speakers, we explore Field Coil speaker drivers, Non-Linear Amplitude Modulation distortion and more.

audioXpress November 2023 offers an exclusive in-depth report on optical MEMS microphone technology from sensiBel, and understand how microphones can impact active noise cancellation performance. Learn how a new ADC Hybrid Gain Control IC enables smooth microphone preamp gain changes, and how to use DSP for hearing enhancement applications. Explore a Motion Feedback (MFB) approach enabling effective active desktop subwoofers, and recap on a century of Home Loudspeaker Development.

Michael Kiwanuka’s article “Current Feedback and Voltage Feedback Fallacies” (audioXpress June 2017) elicited comments from Walt Jung, with supporting signatures from a number of well-known designers, to which Kiwanuka responded. Since some editing errors have crept into the article, we decided to make available a complete correct version of the article, together with the mentioned comments and exchange.

Texas Instruments (TI) introduced the newest addition to the company’s Burr-Brown Audio line, a next generation of the widely adopted OPA1612 audio operational amplifier (op amp). The new OPA1622 delivers lowest distortion and noise, high linear output current, and low power, enabling the highest performance for professional and portable audio applications.