I decided that the sound output from the Pi’s built-in headphone jack wasn’t sufficient after all and so went searching for better options (a DAC—digital-to-analog converter).
The Raspberry Pi foundation created a specification called “HAT” (Hardware Attached on Top) a few years ago which specifies a standard way for devices to automatically identify and configure a device and drivers that’s attached to the Pi via its GPIO (General Purpose Input/Output) pins. There’s a number of DACs now that conform to this standard, and the one I settled on is the JustBoom DAC HAT. It’s a UK company but you can buy them locally from Logicware (with $5 overnight shipping no less).
The setup is incredibly simple: connect the plastic mounting plugs and attach the DAC to the Pi, then start it up and edit /boot/config.txt to comment out the default audio setting:
#dtparam=audio=on
Then add three new lines in:
dtparam=audio=off dtoverlay=i2s-mmap dtoverlay=justboom-dac
Then reboot. (If you’re running Raspbian Stretch or newer, the i2s-mmap line should not be added).
To say that I’m impressed would be an understatement! I didn’t realise just how crappy the audio from the Pi’s built-in headphone jack was until I’d hooked up the new DAC and blasted some music out. I’m not an audiophile and it’s hard to articulate, but I’d compare it most closely to listening to really low-quality MP3s on cheap earbuds versus high-quality MP3s on a proper set of headphones.
If you’re going to be hooking your Pi into a good stereo system, I can’t recommend JustBoom’s DAC HAT enough!