pHAT Module Series
pHAT-HIFI Technical Description
pHAT-HIFI Technical Description
Page 9 of 20
3
Application
3.1
Installation
The module should be attached to the Raspberry-Pi board using a 20+20 2.54mmP pin
header/socket (not supplied).
3.1.1
Line Output Connection
The line output PCB pads, marked L, R & GD can be connected to an external amplifier.
3.1.2
Speaker Power Supply and Speaker Selection
Any mains adaptor with a 2.1mm centre positive connector and output voltage of 9 ~ 15VDC
can be used to power the on-board speaker amplifier, 12VDC recommended. The output
power capability of the adaptor determines the maximum wattage the amplifier is capable of
providing, a 1.5Amp adaptor permitting 2x 8
Ω
6Watt speakers to be driven or a 2.5Amp
adaptor permitting 2x 4
Ω
12Watts speakers to be driven. Ultimate drive performance and
audio fidelity very much depends on the power capability of the mains adaptor.
3.1.3
Speaker Connection
Connect each speaker to one of the 2way terminal blocks noting ‘LEFT SPEAKER’ and ‘RIGHT
SPEAKER’ identification and polarity ‘+’ indication. DO NOT BRIDGE CONNECT ANY OUTPUTS
3.2
Operation
When power is applied to the pHAT-HIFI, from the connected Raspberry-Pi board, the module
will power-up the on-board DAC and is then ready for operation.
When speakers are connected the mains adaptor should also be switched on.
WARNING: When driving 4
Ω Speakers for
a long period of time at a
high volume level the amplifier device on the pHAT-HIFI can get hot.
The device does have thermal shutdown capability but we would
recommend placing a self-adhesive 10*10mm heatsink (ensure that the self-
adhesive pad covers the complete bottom of the heatsink to prevent
component shorts) on top of the device between the two capacitor C15 & C30 if
running the board in this way.
