Usage Examples

Power Supply

You'll need to power your amplifier with a nice supply of power! If you're powering from a wall, check the 5V 2A supply connected to a 2.1mm terminal block

For battery power, a 3xAA battery pack will do well, and can power your amp for at least a couple hours. You can use rechargeable or alkaline batteries, just keep your battery power under 5.5VDC max.

Adjusting Gain

You can adjust the gain on the fly, at any time, by flicking the DIP switches. Start with 6dB setting and adjust up until you have the max gain without any distortion or clipping
If you ever forget, we have the gain/switch settings indicated on the back!

Speaker Outputs

This amplifier is designed to drive moving coil loudpeakers only. Speaker impedence must be 4 ohms or more. The output signal is a 280KHz PWM square wave with a duty cycle proportional to the audio signal. The inductance of the speaker coil serves as a low-pass filter to average out the high-frequency components. Do not try to use this as a pre-amplifier.

The outputs of each channel are "Bridge-Tied" with no connection to ground. This means that for each of the two channels, the + and - alternate polarity to create a single channel amplifier with twice the available power.
However, that means you cannot bridge R and L together, so don't try to connect ROUT to LOUT, it will damage the amp! If you only need one speaker, just connect to either ROUT or LOUT and leave the other output set alone

Connect your speakers using the 3.5mm screw-terminal blocks:

Audio Input Connections

Using the amplifier is really easy - no firmware or special configuration required. In these images we'll assume you're using a breadboard but the wiring is the same if you soldered connections directly.

The easiest way to test your amplifier is to connect a 3.5mm audio pigtail cable to the audio inputs. Connect Right to R+ and Left to L+ then since a 3.5mm audio cable is single-ended, connect the ground wire to both R- and L-

You can connect the power to the board via either a breadboard rail with 3-5VDC on it (say from an Arduino power supply)...
We recommend analog inputs only. If you have a PWM (1-bit DAC) signals, use a filter to get them to analog level
Or you can connect a 2.1mm DC terminal block with + going to VDD and - going to ground as shown here:
If you want to plug in a 3.5mm jack into the breadboard instead of having the cable pigtail, you can wire up a stereo jack as shown below. Tie ground to R- and L- and left and right to L+ and R+
This guide was first published on Feb 04, 2014. It was last updated on Feb 04, 2014. This page (Usage Examples) was last updated on Apr 21, 2019.