No sound from line-out on T4+Audio shield

lerxstrulz

Well-known member
Hey All,

I've run into something for the first time. I've been building an audio project for several years now using Teensy+Audio, and today after assembling and testing one I cannot get sound to come out of the line-out port. The headphone port works fine. It's a simple project that has a mic input, line-out, and plays WAV files from the SD card. Same sketch I've been using. I assembled one before this one and it works fine. I've tried replacing the jack (3.5mm stereo), audio cable, wires from jack to Audio shield line-out poles, using the second set of line-out poles, running several different WAV player example from the Teensy, library, triple checked all the solder points and made sure no pins are cross connected. I've checked continuity from the end of the stereo audio cable all the way to the pins on the Audio shield, including ground, and it's got continuity. I'm not sure what else to try. Has anyone seen this before and is it possible I just got a bad board?
 
No sound from line-out on T4+Audio shield (updated)

Here are pics of a SECOND set of boards put together. Same issue. Headphones jack works but not the line-out. Loaded the WavFilePlayer example provided by Teensy in the Arduino IDE to make sure it wasn't my sketch and same results. Any ideas appreciated!
20220426_193459.jpg
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20220426_182311.jpg
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Could it be that the SDcard housing on the audio adapter is shorting parts on the bottom of the Teensy 4?
See also this thread.

Paul
 
I don't see anything from the Teensy that is touching the SD card housing. I checked that thread and checked the pins again and do no see a short as described there (not that there couldn't be somewhere else.) Also, I have the setup connected to a powered speaker, and if I crank it all the way up I can hear the sound files (very quietly) so it looks like signal is going through but is heavily attenuated.
20220427_080623.jpg
 
Connections on the Teensy / Audio Shield side look ok.

But on the 3.5mm jack, are you sure the yellow wire is in the proper place? Usually the front-most position is GND.

gnd.jpg

Or perhaps that post in the front mates with the sleeve (GND)? Looks like it might be the middle one. Maybe? Difficult to tell from this photo. The other picture with this connector is too blurry to see.

Anyway, I'd double check which pins really are the tip, ring and sleeve.
 
Connections on the Teensy / Audio Shield side look ok.

But on the 3.5mm jack, are you sure the yellow wire is in the proper place? Usually the front-most position is GND.

View attachment 28210

Or perhaps that post in the front mates with the sleeve (GND)? Looks like it might be the middle one. Maybe? Difficult to tell from this photo. The other picture with this connector is too blurry to see.

Anyway, I'd double check which pins really are the tip, ring and sleeve.


Hey Paul,
The connections are correct. However I was able to get this one to work by just putting on the magnifiers and going over each solder connection one-by-one. If I saw anything that looked off the pad it was removed and apparently one of those did the trick! I've been using the 3.2 since 2016 and hadn't encountered this, so looks like I'll need to be really careful with the T4. Thank you for the input and pointing me to the other thread!
 
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