MCM Electronics

20W Amplifier Kit Max9744 By Adafruit (1752) MCM Part #28-19386

5 stars 1 review
MSRP: $19.95
You Save: $0.96 (5 %)
Qty.Volume Price

Specifications Top

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 1KO pot (we include one) 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 (4O, VDD = 12V, THD+N = 10%)
  • Low 0.04% THD+N
  • Integrated Click-and-Pop Suppression
  • Short-Circuit and Thermal-Overload Protection

We took this lovely chip and wrapped it up into a breakout for you, with 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. We also include 3 x 2pin and 1 x 3pin terminal blocks, a 470uF power filter capacitor and 1KO 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.

For more information on installing and configuring this device click here.
Part Numbers
MCM Part #:28-19386
Adafruit Part #:1752
Package Specifications & Dimensions
Weight:0.3125 lbs.
RoHS Comp:Yes
Warranty:30 days
Need to Return?
Length:2.25 in.
Width:1.5 in.
Height:0.25 in.
Shipping Information
Extra Shipping Charge:No
Drop Ship:No

Product Reviews Top

  • by rtims

    on 3/19/2015

    Great amplifier at a great price

    Overall: 5 out of 5

    I purchased this amplifier to use with the steam engine sound simulator for an electric train layout. It has turned out to be an excellent choice, however I did run into a couple of problems. The first problem was I needed it to be analog and the notes on the circuit board didn’t make any sense to me. The kit came without instructions except what is on the circuit board. The Adafruit website ( had an excellent tutorial on how to do make it an analog amplifier. The next problem I had was that the output from the steam engine sound simulator was louder than what was coming out of the amplifier. I used an MP3 player to test the amplifier and it worked perfect. I looked at the output from the player and the output from the steam engine sound simulator on an oscilloscope and the problem was obvious. The steam engine sound simulator output voltage was too much. It was an easy fix with a 1k ohm resister starting on the positive output and a 100 ohm potentiometer ending on the negative output. The output could be adjusted to the optimal signal level. Hopefully this review will help other users to avoid the problems I had as this amplifier is an amazing amplifier with a great output that was a surprise coming from such a small circuit that is also very economical. I highly recommend this amplifier.