audioXpress - March 2017

Special Test & Measurement Focus
18 Audio Precision’s APx1701 Transducer Interface
By Stuart Yaniger
Check out Audio Precision’s APx1701, which when combined with an APx500 series analyzer, creates a test center suitable for measuring speakers, headphones, and microphones, as well as electronics.

28 DIM-100—A Device for Interfacing and Measuring with Sound Cards (Part 1)
Begin with the Design
By George Ntanavaras
Delve into this project and build a device that will enable you to interface and measure using sound cards.

38 Build an Audio Dummy Load
By Gary Galo
Use easy-to-find parts to make your own dummy load and add an essential piece of test equipment to your audio electronics workshop.

44 TM50x Power Module Tester
By Chuck Hansen
Using some ingenuity and know-how, our expert built a tester designed to detect weak filter capacitors and degraded or failed power transistors, on each of the internal DC sources of the Tektronix 50x power modules.

54 Measuring Harmonic Distortion
By Jeff Smith
Discover a few techniques you can use to measure harmonic distortion in your audio signals.

Columns
IT’S ABOUT THE SOUND
8 Streaming Music Experiences (Part 3)
Streaming from TIDAL HiFi
By Ron Tipton

SOUND CONTROL
14 Community Noise Effects and Measurements
By Richard Honeycutt

Hollow-State Electronics
62 Trying Different Output Tubes
By Richard Honeycutt