Review and Measurements of PiFi DAC+ Pi Sound Card
This is a review and detailed measurements of itead's PiFi DAC+ Version 2 Raspberry Pi sound card (DAC). It was kindly purchased by a member and drop shipped to me. It costs US $40 but company has it on sale for US $36.50. It competes with the HifiBerry DAC+ whose pro version I recently reviewed. Unlike that unit, the PiFi DAC+ does not have independent clock source and must be using I^2 S clock. It is said that this clock has more jitter so will be interesting to see if that is the case in measurements.
Here is what it looks like:
The common TI PMC5122 DAC chip is used which retails for $2.40. So not hard to imagine how these things sell so cheaply. There are a few extra bits on this such as a post regulator an IR input port and a 3.5 mm jack. The latter is just mirroring RCA connectors and as such, has high impedance. While it will make sound, don't be tempted to use it as a headphone jack as it will likely have anemic bass and low power levels.
DAC Audio Measurements
As with the other Pi DACs I have tested, I used Ropieee OS image to stream content to the DAC over the network using Roon media player. Here is our dashboard view when playing a 24-bit, 1 kHz tone:
Conclusions
Using the same recipe as the HifiBerry DAC+, the itead PiFi DAC+ falls short in measurements. We were barely good enough with Hifiberry but now are behind the game with some 7 dB higher amount of distortion. Seeing how itead PiFi DAC+ is more expensive anyway, I see no reason to recommend it over HifiBerry offerings.
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My I2S DAC (P1F1 DAC+ v2.0) works perfectly with RuneAudio release version: 0.4 (build: beta-20141216) with the audio output setting as HiFiBerry DAC+ (I2S). The sound is astonishing and better than most of USBDAC interface.
Only trusted workaround that can be found for your DAC or AMP is on the following link.
first find your DAC that are listed on the link and follow the steps to make your DAC
work properly. I have PiFi DAC+ (AliExpress) and it worked after I followed the steps given
under the section of
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Note that this card has an IR receiver built in. The IR receiver is connected to GPIO26. Remove JP2 to disable the IR receiver.
sudo nano /etc/modules
Comment out (#) the following line:
snd_bcm2835
Add the following lines:
bcm2708_dmaengine
snd_soc_pcm512x
snd_soc_hifiberry_dacplus
snd_soc_bcm2708_i2s
Now we need to load the correct device tree file by editing /boot/config.txt:
sudo nano /boot/config.txt
Add the following lines at the end of the file:
dtparam=i2c_arm=on
dtparam=i2s=on
dtoverlay=hifiberry-dacplus
Save the file (Ctrl-X, Y, Enter)
Create the sound.conf file as follows:
sudo nano /etc/asound.conf
pcm.!default {
type hw card 0
}
ctl.!default {
type hw card 0
}
Save the file (Ctrl-X, Y, Enter) and reboot
sudo reboot
After reboot, check if the DAC is selected as your sound card:
aplay -l
You should see this:
card 0: sndrpihifiberry [snd_rpi_hifiberry_dacplus], device 0: HiFiBerry DAC+ HiFi pcm512x-hifi-0
Subdevices: 0/1
Subdevice #0: subdevice #0
Make all changes to /etc/mpd.conf as described in "Build the software".
Install mediaplayer as described in "Build the software".
GPIO Pin Usage:
GPIO2-3 are used for configuration. GPIOs 18-21 are used for the sound interface. You can’t use them for any other purpose.
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The output level is a hair higher than HifiBerry DAC at a little over 2 volt which is fine. What is not so fine is the much lower SINAD (signal over noise and distortion). While the HifiBerry DAC+ PRO achieved 92 dB, we have a shortfall of 7 dB. This places the PiFi in our bottom tier of all DACs tested to date:
Multitone test likewise shows a step down in performance:
I like to see 95+ dB here and we are way short of that at just 78 dB.
Jitter response while again worse that HifiBerry DAC+ Pro, is still quite good:
So not sure what all the screaming is about regarding the I^S Clock. The DAC chip's PLL is likely cleaning it up good.
Filter response is different flavor of bad from HifiBerry:
As with Jitter, probably not an audible concern though.
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