ProtoDAC TDA1387 X8 project

[eculcea]

I am just a hobbyst as well. I recently added the test method in Post #1 of this thread.

Make a simple module test rig with one of your spare PCBs with GPIO soldered, three I2S resistors (R1-R3), a socket for the module (14 pin DIP socket OK), two metal film 430R I/V resistors (U7/U8) and 2000uF power supply decoupling cap (C3/C4). There is no need for any other parts on the test rig. Download this 60s_Sine_50Hz_0dB.wav file and play on Moode with repeat track on. Measure AC RMS voltage at the two test points, which are the output coupling cap pads at the I2S resistor end of the PCB. Measure between test point and ground. Voltage should read 1.2-1.3 Vrms, and the two channels should read very closely. I reject modules for the kit that can't pass this test. I do think modules that read 1.10-1.19 are good, but I only include 1.2-1.3 Vrms modules with the kit.

I hot swap modules and wear a grounding strap.

Most DMMs are accurate at 50 Hz, and accuracy suffers as the frequency increases.

I apologize, I missed your first post. I have the module installed in a socket and I "tested" it by using my ears. After reading your post of 10% failure rate of modules it got me thinking, my ears might not be good enough to find a bad module.