Volumio - bookshelf edition

Written by employee #33. Posted in just going through the motions

Some note about my take on a Raspberry/Volumio box. This is not a expert how-to or anything like that, but just stuff that would be nice to avoid; things I would have liked to know before i started. I.e. if you are not super electricity minded, you might find something useful.

Bookshelf size Volumio box.

Conclusion: Very happy with Volumio and what i can get out of the box. Started out with local flac files, but today I use it mostly for listening to radio stations. Lots and lots of very good stations out there. Phone/pc is the most convenient way to use Volumio - no need for a screen. Without the screen you also avoid issues with power and constraints with the case and should be simpler (and cheaper) to build

I have not compared Volumio to a lot of other streamers, so not really a lot to say about the reason why i have chosen Volumio. But it is very simple to install and found other users who was also using a Schiit DAC with Volumio.

 

‘End-game’ setup: Raspberry Pi 3b+, 7” touchscreen (official), ifi power brick and a digital interface hat. External USB disk with powered USB hub. The DAC and amp is Schiit.

Box was intended to fit on a bookshelf. I therefore used an box not much larger than the 7” screen. Definitely too small. The box, screen (only the back of is visible), Raspberry Pi board, AK4118 digital interface hat, Schiit DAC/amplifier, powered USB hub and USB disk. The fat red cable connect the AK4118/SPDIF port to the DAC SPDIF port. For the final version, the MeanWell PSU was replaced with ifi Audio iPOWER (5V 2.5A). Power is added directly to the AK4118 hat. Hat is powering both the Raspberry Pi and screen (with two wires going from the AK4118 pins directly to the screen.

 

About the 7# screen. Not sure why i thought the screen was so important. You should really try to avoid it if you can: Not really useful and you can avoid a lot of problems with power issues if you run without it. Most streaming projects (including Volumio) have some kind of app or webpage with the same functionality as the screen. Phone/PC is typically the most obvious choice when using Volumio. Without the screen you can also hide the box completely and the choice of case will be irrelevant - just keep the pieces together and offer some protection.

USB cables. Possible everybody know this, but I didn’t so here it is: In regards to putting current through an USB cable, there is a huge difference between different USB cables. Some cheap ones was good, but mostly expensive cables are better at carrying current. Have not found any standard for these thing, but had luck with every ‘Fast charging’ cable I testet. Sound reasonable. Length of the cable can also influence power drop. Obvious is shorter better. A undervolt issue can arise from a bad cable - not necessary form the power supply, so check with different cables before buying new hardware.

PSU/power supply. Used a lot of time on figuring out how to fix a persisting undervolt problem. From what I understand: When too much power (watt) is drawn from a PSU, voltage will start dropping. When it drops below 4.65 volt, Raspberry pi will start to undervolt (small yellow lightning symbol will show up on the right upper corner). When this happens one of the result is the clock speed is reduced. Found a lot of post about bad read/write and consequently corrupted OS, but never had any of that. I just found (completely unsustained) that undervolting caused problems with the sound.

Without the digital interface hat and with the Meanwell PSU I kept getting random pop sound. Pop or click noises. Added the AK4118 digital interface hat AND the ifi PSU. That solved the problem, but i am not sure what actually happened here; either the new psu or the digital interface (or some cable/wire was changed with a better one). The test i have run with the AK4118 and the Meanwell PSU have been to few.

I will recommend to start out with the officiel Raspberry Pi 5V/2A power supply. It is cheap and you properly already have one. With the screen but without the AK4118 digital interface hat added, it will only occasionally undervolt. I have not tested with both screen and hat with the official Raspberry pi psu.. Every other 5V/2A phone charger have undervolted.

ifi connected to the hat (top right). Screen powered directly from the hat. Wires connected from the hat to the screen:

Screen:
RED: Pin 2 (5 V power)
BROWN: Pin 6 (Ground)

Button:
BLUE: Pin 5 (SCL)
GREEN: Pin 14 (Ground)

Should be possible to avoid the wires and connect to the screen instead:

Power brick (micros usb) - Screen (micro usb)
Screen (usb A) - Raspberry PI (micro usb)

Less wires, but could not make this work. The button setup (pin 5 and 14) will work without a script as turn-on button. Not for shutdown. The source I used: https://howchoo.com/g/mwnlytk3zmm/how-to-add-a-power-button-to-your-raspberry-pi

  AK4118 digital interface for SPDIF Raspberry Pi 4 / Pi 3

Note: I thought my PSU was the official Raspberry Pi one and as this was undervolting constantly, I thought I needed something with more amps. I therefore tried to setup a MeanWell, RS-15-5 (15W 5V 3A) as power supply.

The MeanWell is fine when using a direct cable between the psu and raspberry. I.e. split one end of a USB cable. Find the two power wires (the other two are data) and connected the micro usb directly to the raspberry. Fix the undervolt problem (99.5%) at 5.25 volts and the RS-15-5 is completely silent. But I was not keen on have the Meanwell semi enclosed case laying around and needed 220v power and usb connectors, so i added another Amazon box. Best thing would be to choose a big enough box for the complete project - including the psu. The Meanwell takes 220 volt input. Later replaced it with a ifi power brick.

 

Adding 220v ( upper left) and USB connections (button) to the meanwell psu. The usb power wire a crazy thin (top right) and made of what looks like … aluminum?

PSU do influence the sound. The official Raspberry PI, Meanwell og ifi PSUs all produce a distinct different sound. For my specific setup and headphones I tends towards the Meanwell PSU.

Digital interface: Very possible the following is wrong. The details about the problems are correct, but i have really no evidence for the solution - check other sources). I had a problem with random clicking and popping noises. Only when streaming web sources. As the DAC is connected to a USB port on the Raspberry PI, I am guessing the problem have something to do with ethernet and usb is both using the same controller. So a SPDIF digital interface should remove this bottleneck? With the AK4118 hat the noises is gone, but as I don’t know what caused the problem, so I am not really sure what the solution was.

Compared with a HIFIBerry DIGI hat, the AK4118 offer access to all the Raspberry Pi pins - without solder.

  MeanWell RS-15-5

Case size: Could not find a Raspberry Pi screen case I liked. The standard ones are expensive and would fit badly for what I was aiming for. Instead I found a inexpensive wooden box on amazon - just about the size of the screen. I will still recommend making your own enclosure, just make sure it is large enough. I used a box slightly bigger than the screen, and it simply complicate things unnecessary. The box measured: 20 (height) x 12 (width) x 8 (deep). Height and width you can possibly live with, but you will get some nice bonuses with a much deeper case. Even perhaps 12-15 cm. With a case of 8 cm deep it is impossible (for me) to fit build-in (or pass-though) UBS, RJ45 and RCA connectors. I.e. without the connectors, every cable is now connected directly to the Raspberry PI or hat. I would have liked to be able to disconnect the box from all the cables - will be added in version 2. In the current small case, the Raspberry is running steady at 59-60 degrees without active cooling.

USB disk. Could not run Volumio with the external disk, without the powered USB hub. I.e. USB disk should not get power from the Raspberry. Same result with the official Raspberry PSU and the IFI. Again; not sure why I bothered with the disk. I do not use it.

MeanWell, RS-15-5 . Switching power supply for LED 15W 5V 3A. Amazon DE. 10 Euro.
ifi Audio iPOWER AC-DC Adaptator / Low noise Power supply 5V 2.5A. Audiophonics (https://www.audiophonics.fr)
AK4118 digital interface for SPDIF Raspberry Pi 4 / Pi 3. Ebay/Audiophonics.

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