Speaker pHAT sound deterioration


#1

After following the setup instructions for the “Adafruit MAX98357 I2S Class-D Mono Amp”, I had this HAT working, The sound level, seemed about right for a reputed 0.5W output. After an hour or so, the audio became overlaid with what sounded like digital noise almost masking the original source. Suspecting software issues, I laid the HAT aside until I found your single line installation instruction.

Fresh installation of Raspian Jessie (2017-1-11), the obligatory update & dist-upgrade, then your single-line install: The sound output is very low, the “left, right,…”. of speaker-test -c2 -t wav being barely perceptible more than 1 foot from the speaker; using Mathematica to generate a pure sinewave tone, the resultant is horribly noisy and distorted. Is this more likely to be hardware or software related?


Speaker Phat sound diminished
#2

using alsamixer, make sure the output level is at 80+… not sure if that’s the issue but it sounds like it could be.


#3

alsamixer playback level is set to 100.


#4

I’ve just completed a fresh install on another RPi, same as before, plenty of lights, little sound.


#5

have you soldered the pHAT onto the header? are you using select wiring or popping the pHAT onto the Pi as expected? can you post a picture of your setup for us?


#6

Yes the pHAT is soldered onto the header. Image shows the pHAT attached to a RPi 2B, the problem remains whether I use a model 2, 3 or zero.


#7

I can’t see anything wrong with the soldering.

… I’m not convinced it is hardware related if you had a respectable volume initially, but if you tried on a clean install with our software stack then that’s still the most plausible.

please, send an email to support@pimoroni.com and request a RMA, they will swap the unit and hopefully that will be the end of your troubles!


#8

just to check though, have you seen the assembly guide and have followed it to mount and wire the speaker on the underside right?

https://learn.pimoroni.com/tutorial/sandyj/assembling-speaker-phat


#9

Four nuts as spacers - ✔
Soldering looks OK - ✔

Guess, I’ll have to RMA it.