Connecting Teensy 4.0 + Teensy Audio Shield with Adafruit Class D Amplifier

Not open for further replies.


New member
Hello guys!
I am totally new on this topic, never used arduino or teensy or anything like that before, and I know only the basics of electronics (I know programming, that part shouldn't be that hard), but I need to make this project! Please help me.
Today I got the Teensy 4.0, the Teensy Audio Shield and the Adafruit Stereo 20W Class D Audio Amplifier - MAX9744. I already attached the Teensy Audio Shield to the Teensy 4.0, that was straightforward thanks to the pins aligments, very easy, and it worked perfect, made some tests with the Teensyduino.
But now, how do I make a connection between the Teensy boards and the Adafruit?
My main goal with this project is to play some WAV files from the Micro SD card, and output the audio from the apmplifier to a pair of speakers.

Thank you!
The Audio shield has pads for connecting line-in and line-out - you need to connect line-out to the amp.

As supplied these pads are unpopulated, so some soldering is needed. Some pin headers could be used,
or just wire directly to a 3.5mm stereo plug.

I have a caveat - some class D amplifiers will interact with the sample rate clock and could produce audible
tones if the intermodulation products fall into the audio band, so there's a risk of this. The Adafruit board
seems to set the chip in spread-spectrum mode so if there is a tone it will be fluctuating.
Thank you so much. I have been reading a lot about all this. So I made representation of what I understand and I would like to know if this is correct:


Let me know if I am missing something. Specially in the powering part, I don't quiet understang how should I power the Teensy boards, I guess the amplifier should power the Teensy 4.0 via the 5V (using a voltage regulator). Is that correct?
Also, I want to control some aspect of the audio with a potentiometer (like bass and treble, maybe volume too), so how should I connect the potentiometer? I am strugling with the hardware side.

Thank you,
Volume is done with the amp object, tone controls are trickier as you'll have to figure out the filter response you
want and encode that with the biquad filter object.

The pots would be read using analogRead() regularly and the audio objects' parameters updated to match the
current value.
Not open for further replies.