All or just the standard DAC board(s) to be made to the size of the Raspberry Pi Zero so they sit on top of the board and could be used as an ultra small form factor audio server/player. I believe the DAC+ works with the Zero, but the HAT board dwarfs the little Zero board!!
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hifi I think this is not a good idea to mention DAC from another company on this site.
But you can easily find it by googling. BTW that DAC uses the same driver/overlay
as HiFiBerry DAC. I'm making such Pi Zero player right now. It will be battery powered
player. There will be Pi Zero + DAC + amplifier (3W) + LCD (2.2") + speakers(3W). It
will be controlled by IR Remote and from any web device.
The hardware and software part is actually completed. The main issue which I'm trying
to fix is the noise in speakers. I'm using +5V from Raspberry to power small 3W amplifier.
That causes a lot of noise with any PS which I tried. Also it doesn't matter if I use
WiFi or wired connection. Probably battery will not be so noisy but I want to power the
player from the regular power supply as well.
I setup hardware and software on my spare Raspberry Pi 2 and then just move
hardware and SD card to Pi Zero. This way you don't need tricky connections required by
Pi Zero.
Probably another good product idea would be integrated amplifier in a Pi Zero form
factor. Especially if it would fix that annoying noise problem :) -
hifi As I said that DAC is using HiFiBerry's driver. Therefore setup is the same.
You can do that either manually or by running their script.
As fo the noise I'll try to add some simple Capacitor-Ferrite filter first
and see if that will solve the problem (more likely not). Another idea is
to add LT3080 regulator conneced to RPi's +5V and power amplifier from it.
It has low dropout ~350mV. So hopefully it should not affect amplifier that
much. Thanks for your proposals. I'll check them as well. -
hifi FYI, I have tried three different options to get rid of noise in speakers. The two options which I mentioned above (LC filter and LT3080) didn't help to reduce the noise. More likely that's because in both cases there is still common ground. Only isolated power chip MORNSUN B0505S-1W helped to kill that noise:
http://www.ebay.com/itm/5PCS-B0505S-1W-DC-DC-5V-to-5V-Isolated-Power-Module-for-MORNSUN/351756162581
That chip provides 200 mA. If you need more power you can connect them in parallel. Just connect outputs through diodes. -
Stephen Ludgate Great update, thanks hifi. I think I will get some of those for future audio projects. Seems like a winner there!
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hifi Thank you for the hint Stephen!
Here is one more solution if you power amp separately from RPi and have noise through the signal line:
https://www.amazon.com/ZIOCOM-Isolator-Eliminate-Buzzing-Completely/dp/B019FC6ZQQ
They don't describe how it works but if it's not isolated design I doubt it works well. More likely this is just LC filter(s).
I connected 3 MORNSUN chips in parallel to feed 3W amp. According to the spec:
http://mornsun-power.com/pdf/DCDC%20Converter/B_S-1W.pdf
they are 80% efficient. With medium volume they become warm. Hopefully I don't need to use heatsink. We'll see.
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