VoltaStream ZERO


Tiny audio streaming module running Linux with built-in high quality DAC, digital TOSLINK output and full-sized USB A connector as well as micro USB input and WiFi. Measures only 65 x 30 mm and offers access to 28 GPIO’s.

This is an evaluation board/kit! Read this important notice!

Have a look at the FAQ’s and choose a configuration:



VoltaStream ZERO is the perfect choice for streaming your music. It includes a high quality analog output as well as a optical TOSLINK transmitter. For smallest footprint the optical audio output is directly integrated into the 3.5 mm line-out jack. There is also a full-sized USB-A connector where you can easily connect the included and free-of-charge USB WiFi dongle.

VoltaStream ZERO is actually less expensive than e.g. a Raspberry Pi ZERO if you add the same audio functionality and a case!
For a Raspberry ZERO you would have to pay (incl. 19% German VAT):

  • Raspberry Pi ZERO W (12,- €)
  • Common I2S DAC (24,- €)
  • Common TOSLINK HAT (26,- €)
  • Simple case (6,- €)

Results in 68,- € (Raspberry Pi ZERO W) versus 49,- € (VoltaStream ZERO).  With a Raspberry you will end up with a very bulky solution with several limitations and a lot of fiddling on the software side. VoltaStream ZERO is fully integrated and thanks to PolyOS all features are perfectly supported.

VoltaStream ZERO is powered via 5V from a microUSB connector that can also act as a USB gadget device. Furthermore it is fitted with a microSD connector from which it will boot one of our supported Linux distributions.

It measures only 65 x 30 mm and features a 40 way pin-header with access to 28 GPIO’s. The layout is similar to the Raspberry Pi ZERO but the position of the connectors were optimized for audio usage. The functions of the GPIO’s are fundamentally the same but might differ a little in detail. We are targeting to get the common audio hardware add-ons (HAT’s) available for Raspberry Pi working with our board, too. For more details please see the System Reference Manual available from the Documentation tab.
It also comes with an integrated real-time clock as well as a dedicated On/Off button handler.

We believe in openness so VoltaStream ZERO is fully open-source! All KiCAD schematic and layout files are available under the CC BY-NC-ND 3.0 license. Furthermore the board is designed + manufactured in Germany and we are providing a custom Linux distribution especially created for this hardware. If you ave a special problem to solve never hesitate to contact us. We are here to help you where we can!

Read the full story of how VoltaStream ZERO was born HERE.

Version with 1GB RAM and/or PCM5142 for volume orders only!
This board is designed in / made in / shipped from Germany!
We are also offering customization service even for low-quantity!


Packaging contains:

  • one VoltaStream ZERO board
  • one Edimax EW-7811Un WiFi module
  • four long screws
  • four short screws
  • four normal spacers
  • four spacers with internal thread
  • two wooden plates engraved and with mounting holes


Additionally you will need:

  • microUSB cable for power supply
  • microSD card with at least 2GB capacity
  • microSD card reader for flashing the operating system from your host computer
  • miniTOSLINK cable (or adapter) or 3.5 mm analog audio cable for connecting VS0 to your amplifier


SOC typeNXP i.MX6ULL commercial grade
SOC specARM Cortex-A7 @ 996 MHz
RAMDDR3 - 512 MB or 1 GB
Power managementexternal discrete solution / partly integrated into SOC
Power supply5V via microUSB or GPIO header
Power consumption0,10 Watt - Linux suspend
0,25 Watt - Linux idle
1,10 Watt - USB WiFi busy
USB1x USB-A host
1x microUSB slave
Digital audio1x I2S for integrated DAC
1x I2S for GPIO access
1x S/PDIF header / TOSLINK jack
Analog audiointegrated DAC with H/W volume control powered by ultra low noise LDO - PCM5121 or PCM5142
GPIO header5V, 3V3, GND, 2x UART, flexCAN, 2x I2C, SPI, I2S, 3x PWM, S/PDIF INPUT
On/Off switchintegrated button handler / accessible from header
Real-Time-Clockintegrated into SOC


Below you can find support material in PDF format. If you have additional questions never hesitate to contact us directly.

Getting Started

A short summary for how to get started. Shows you where to connect everything and includes instructions for how to prepare a SD card, setting up network and how to stream your first audio samples.

Version: REV A
Release date: 2017-08-01

System Reference Manual

Everything explained in detail. Here you will find all hardware related things like dimensions, power supply and accessible GPIO’s. It gets you also covered with details about the Linux kernel and the U-Boot bootloader.

Version: REV A
Release date: 2017-08-01


The full schematic of VoltaStream ZERO in a handy PDF. Everything you need to understand how the hardware interacts.

Version: REV A1
Release date: 2017-08-01

Hardware Files

VoltaStream ZERO is fully open source. So the full KiCAD project files are available from GitHub.

Version: REV A1
Release date: 2017-08-01


Below you can find a list of operating systems that can easily be flashed onto a microSD card and will bring your VoltaStream ZERO to life.


The operating system specially created for VoltaStream from scratch. It is based on Yocto, super light-weight, offers the most important streaming services and should give you the best out-of-box experience. It currently includes shairport-sync, a DLNA renderer, librespot and a special update mechanism. This is a work-in-progress and we are working very hard on improvements. There are also plans for a dedicated smartphone app which will expand the feature list a lot. You can expect updates several times a month. They may by visible through the integrated updater first before they get published here.

Release date: 2017-08-08
ChangeLog : LINK
SourceCode: LINK


PolyBian is based on Debian which is a widely spread Linux distribution and will give you an easy entry point if you want quickly create something on your own. For example it is known from Raspbian – OS for the Raspberry Pi – and you can easily reuse guides and instructions were initially made for Raspberries. This distribution does not come with any audio related software by default but you can easily install it on your own. Includes drivers for our tested USB WiFi sticks as well as the DAC and the TOSLINK output. Updates not on a regular basis and requires refreshing each time.

Version: 2017-07-28-polybian-stretch
Release date: 2017-07-28
SourceCode: LINK


Volumio is an open source audio distribution based on a webfrontend. You can use your browser to change settings and control playback. For all details have a look at there website. www.volumio.org

After flashing the image, power up your VoltaStream ZERO and wait about 5 minutes. A new WiFi access point called “Volumio” is automatically created. Connect to it with the password “volumio2”. Now a captive portal should automatically pop up on your device. Go to settings -> network and enter the credentials of your personal WiFi access point.

Officially Volumio only supports devices with at least 1GB RAM!

Version: 2.258-2017-08-16
Release date: 2017-08-16



Install Instructions

See the GETTING STARTED guide available from the DOCUMENTATION tab.



Please find several frequently asked questions below. From time to time we might add topics if we see a demand for clarification.

Which RAM size should I choose?

This depends on what you want to achieve with your board. While on commercial streaming products 256 MB RAM is widely spread our standard version contains 512 MB to be future proof. Lately some third-party Linux distributions recommend 1 GB of RAM. This is due to the fact that their internal architecture isn’t especially designed for embedded devices. So if you want to use our own software (PolyOS) choose 512 MB. If you are unsure or want to use demanding third party software choose 1 GB.

Which DAC type should I choose?

The standard version features a PCM5121 from Texas Instruments / BurrBrown. It offers a full-scale 2V RMS LINE output and has a really good signal-to-noise ratio (SNR) of 106dB. We are also offering a PCM5142 version which raises the SNR to 112dB and also includes a small DSP (that currently isn’t supported by our software). The PCM5121 does offer excellent audio quality. Much better than most standard commercial solutions. Only choose the PCM5142 if you see a use for yourself in the slightly better specs.

Where is the TOSLINK output and can it be used at the same time with analog output?

The optical TOSLINK output is directly integrated into the 3.5 mm audio jack and requires a small adapter if you want to use a standard optical cable. It is not directly possible to use both at the same time as the jack only accepts one plug. Both the analog and the digital output are also accessible via though-hole solder joints. So for example you could plug a TOSLINK adapter into the 3.5 mm jack and solder your analog cables directly to the solder joints. This way you can have both at the same time.

Why is there no super-fast multicore processor?

We have chosen to use a very well documented and perfectly supported processor (SoC) with long term availability. For audio streaming no powerful processor is required. The one we are using is much faster than required for such simple tasks and offers a lot of headroom. So really nothing you should be concerned about. Furthermore it consumes much less energy than multicore processors. This is a very important point as it will be in always-on mode most of the time.

What about WiFi?

VoltaStream ZERO comes with a free USB WiFi dongle for best network connectivity.

Is VoltaStream ZERO certified for CE, FCC, … ?

No, it is sold as a evaluation board/kit and does not need certification. It is not considered to be a finished end-product fit for general consumer use. Persons handling this evaluation board/kit must have electronics training and observe good engineering practice standards. Read the full disclaimer under which we are selling our hardware HERE.