sparkfun DEV-14475 Hook-Up Manual page 6

Stereo Amplifier Wiring
To get the full output power from the amplifier you'll need to configure the Noisy Cricket as a mono amplifier. When
configured as a mono amplifier, the left and right input channels are combined to drive a single speaker.
To enable mono operation, use solder to short the two pads labeled "ENABLE MONO OUTPUT" on the back of
the board. It's also recommended to close the other solder jumper labeled "MONO BASS BOOST". Each output
has a 100μF decoupling capacitor that is used for stereo amplification. In mono mode however, the output doesn't
need to capacitor and will filter out some of the lower bass frequencies and as a result, the audio will sound more
"tinny". The mono bass boost jumper shorts the left output decoupling capacitor which will allow the lower
frequencies to pass.
Mono Operation
In mono operation, the output has a maximum power output of 1.5W (with a 4Ω load). To connect your speaker
you'll need to connect one pin of the speaker to the left output pin, and the other to the mono output pin (but NOT
GROUND!) as shown below.
Mono Amplifier Wiring
Choosing a Power Supply and Speaker(s)
As mentioned in the previous section, the Noisy Cricket has an output power of up to 300mW/channel in stereo
operation, and 1.5W in mono. The power output depends on not just the output load, but the power supply as well.
Borrowing a few graphs from the datasheet should help us understand our power supply and speaker selection.