The two amplifier chips use the 3V + 5V + GND power pin at the 'top' of the 2x20 header. If using 3W speakers, you can draw a significant amount of current, over 1.5 Amps! Make sure you power your Pi with a good wall adapter like our 2.4A microUSB power plug.
5V 2.5A Switching Power Supply with 20AWG MicroUSB Cable
Alternatively, if you really need a lot of power, use a 5V 4A power adapter and then a DC to micro USB adapter
5V 4A (4000mA) switching power supply - UL Listed
MicroUSB Plug to 5.5/2.1mm DC Barrel Jack Adapter
The Bonnet uses 3 data pins and they cannot be changed! Pins #18, #19 and #21 are used. All other pins are available
This is the fun part, you get stereo output - one left and one right channel. Each one is Bridge-Tied-Load so do not connect both outputs together to get more volume!
You can use the JST 4-pin plug in the center if you're going to just plug in one of our enclosed speaker kits:
Stereo Enclosed Speaker Set - 3W 4 Ohm
OR
You can use the terminal block spots on the left & right to connect regular speaker cones. You'll need to solder wires on and such but this way you can use whatever speaker you like! We suggest 8 ohm 1W or 4 ohm 3W. For louder audio, but more power usage, use the 4 ohm speakers. For quieter audio, but less power usage, use the 8 ohm speakers
Speaker - 3" Diameter - 4 Ohm 3 Watt
Speaker - 3" Diameter - 8 Ohm 1 Watt
You can also use other 'audio' devices like sonic transducers! These are devices you can put down onto a surface like a table, to make it into a speaker.
