Adafruit Stereo 20W Class D Audio Amplifier - MAX9744

by Adafruit

Pump up the volume with this 20W stereo amplifier! This slim little board has a class D amplifier onboard that can drive 2 channels of 4-8 ohm impedance speakers at 20W each.

Power it with 5-12VDC using the onboard DC power jack and plug stereo line level into the 3.5mm stereo headphone jack and jam out with ease. Since it's class D, its completely cool-running, no heat sinks are required and it's extremely efficient - up to 93% efficiency makes it great for portable or battery powered rigs.

We like the MAX9744 amplifier at the heart of this board because its very easy to use, but it also has both analog and digital volume control capability. Use a single 1KΩ pot (included) to adjust volume analog-style. Or hook it up to your favorite microcontroller and send I2C commands to set 64-steps of volume amplification.

  • Power from 4.5V-14V DC voltage
  • Up to 93% efficient (88-93% typical)
  • 20mA quiescent current (or put into shutdown for 1uA quiescent)
  • Up to 29.5dB max gain
  • Use DC or AC coupled line-level input, up to 3Vpp
  • Filterless Spread-Spectrum Modulation Lowers Radiated RF Emissions from Speaker Cables
  • 20W Stereo Output (4Ω, VDD = 12V, THD+N = 10%)
  • Low 0.04% THD+N
  • Integrated Click-and-Pop Suppression
  • Short-Circuit and Thermal-Overload Protection
  • Includes polarity-protection, jacks and terminal blocks, i2c level shifting, and a spot to solder in a volume pot.

Each order comes with one MAX9744 breakout board with all surface-mount parts fully assembled and tested. Included are 3 x 2pin and 1 x 3pin terminal blocks, a 470uF power filter capacitor and 1KΩ trim pot.

To use this board, a little soldering is required to attach the terminal blocks and other components, but its fairly easy and expect it should take less than 15 minutes. Check out Adafruits detailed tutorial for assembly instructions and overall usage

7 customer reviews

6 years ago
I really like this pcb. Of course it would be so much better if it could give something for nothing, i.e. not need 12V supply to deliver 20W, but do it from a LiPo. But perhaps that is the fault of physics rather than this board? The issue for us is space, how can this be incorporated into a moveable tactile object like a wooden hollow form, without having a power supply lead or have a large/heavy battery hidden inside a relatively small object that is then out of balance...? It is a creative challenge and a good one to ponder... for projects that have a power cable or enough space to include a 12V battery, it is great.
by Dave about Adafruit Stereo 20W Class D Audio Amplifier - MAX9744 via REVIEWS.io
8 years ago
This amplifier, a couple of 4", 21 Watt RMS speakers for about ВЈ15, a universal laptop supply for about ВЈ12 and a wooden case make an excellent boom-box for your phone, computer etc. The amp provides enough power to severely rattle the speakers and necessitate nyloc nuts to secure them in place! A 12 volt, 4 amp supply will be needed for full power so the usual unit used for an Arduino, say, won't be enough. My only criticism is in the surface mounting of the power socket. The pads are just not strong enough to secure a socket of this size. (Look at the Arduino Uno, for instance. Its power socket is soldered through the PCB.) Recently, a small accidental tug on the power lead caused the socket on my unit to pull away from its pads. I recommend that power be transferred from the screw terminals to a separate panel-mounted socket to avoid any problems.
by Julian about Adafruit Stereo 20W Class D Audio Amplifier - MAX9744 via REVIEWS.io