How to Use Supstronics X400 Expansion Board




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This will show you how to use the Supstronics x400 Expansion Board with Raspberry Pi.
Check it out here

First of all what is a Supstronics x400 Expansion Board?

Here are its key features:

Input Voltage - 6V to 24Vdc converted to 5V, 3A via step-down DC/DC converter to power the Raspberry Pi
- Full-HD audio– up to 24-bit/192kHz playback
- Class leading audio; 112db SNR, and THD of 0.0019%
- Audiophile TI Burr Brown 32-bit/384kHz DAC (TI PCM5122)
- Uses the digital I2S audio signals to reduce CPU load over USB audio solutions
- Integrated hardware volume control
- Mute can be enabled / disabled via jumper
- Built in High quality audio headphone amplifier (TI TPA6133A)
- Earphone AMP can be enabled / disabled via jumper
- Built in High quality Class-D stereo audio amplifier (TI TPA3118D2)
- Up to 2 x 20W into 4 ohm
- AMP can be enabled / disabled via jumper
- Phono/RCA connectors
- 3.5mm stereo audio jack
- Speaker terminals
- Built in IR sensor (38KHz)
- DIP switch to remove connection from RPi’s pin header
- Directly connected on top of the Raspberry Pi using the board GPIO header pins
- No wiring nor soldering is required
- Duplicated the 40-pin header of the R-Pi in order to support existing expansion boards
- Suitable for Raspberry Pi Model B+, Raspberry Pi 2 Model B and Raspberry Pi 3 Model B NEW!
Dimensions - 85 x 56mm (Same size as Raspberry Pi)

Step 1: Build the Setup

Just put the standoffs on then screw it all down. It's simple.

Step 2: Edit /etc/boot.txt

You are now going to need to edit /etc/boot.txt so we can change the soundcard.

First in the terminal (ssh) type:

sudo nano /etc/boot.txt

Once that is open add the fallowing line:


Step 3: Edit /etc/modprobe.d/raspi-blacklist.conf

Enter the fallowing into the terminal(ssh):

sudo nano /etc/modprobe.d/raspi-blacklist.conf

Comment out these lines (if they exist):

blacklist i2c-bcm2708

blacklist snd-soc-pcm512x

Step 4: Edit the /etc/modules File

Enter the fallowing into the terminal(ssh):

sudo nano /etc/modules

Then add the fallowing:






Step 5: Setup OSMC Audio Output

1) Go to "My OSMC"

2) Click on "Pi Config"

3) Make sure the right soundcard is selected, then click ok.

Step 6: Test It Out!

WARNING!!! - Do Not Power the Raspberry Pi through the Micro USB Port. Use the DC Plug on the x400 Board

Plug everything in, the sound quality is awesome.

I hope you enjoyed the project! If you have any questions leave them in the comments.

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    19 Discussions


    Question 11 months ago on Step 1

    Sorry for the long comment. I bought one of these X400 boards a few weeks ago on Amazon. In case other folks are wondering if it works on a Raspberry Pi 3 B+ with Volumio 2, I got it working in spite of being a Linux noob. Being a noob, it took me over a week to get my setup 95% working. (I still need to set up Bluetooth and build a rechargeable LiFePo4 battery power system.)

    It turns out the Volumio 2 distribution was missing a bunch of packages which I needed for my build and it took me a week to figure out which ones by trial and error. I really wish I had found your excellent and simple instructions BEFORE I assembled it! I would have saved at least a couple days. LOL

    *Side Note: In my build, I also got a Sunfounder 10.1-inch touchscreen to work with Volumio 2 and found a way to store all of my FLAC music files on the same internal boot 256GB microSD as the OS. This will hopefully boost the battery runtime. As a result, I now have a self-contained touchscreen audiophile music player module that I can use to build high-end portable tabletop stereos and boomboxes. I'm ecstatic with the end result but I'm also somewhat worried that all my random tweaks may have messed up Linux in some way. I was going to try to write up instructions for the whole build, but I really don't know Linux well enough to give accurate information. I'm also sure I made dozens of unnecessary changes. I basically hit the bull's eye by throwing 3,000 darts at the target. ;) I'm that theoretical monkey who accidentally wrote War and Peace by randomly hitting keys.

    I have a few questions I hope you can answer:

    1. You mention not to power the Pi via the micro USB port. I didn't know this, so I've been powering the Pi using a Mackertop 5.25V 3A micro USB power supply. (Note: By far, the best Pi3B+ power brick I have found. Everything else triggers the low voltage throttling on a Pi3B+. This includes the most recommended Pi3B bricks on Amazon.) Fortunately, I've been lucky. It hasn't fried my Pi yet, but I suspect it's because I have had the X400 amp disabled during my testing. Apparently, the X400 can be powered as a line-out or headphone-only device directly from the Pi 3B+'s GPIO pins. In fact, there is currently no external power source going to the X400 board because I'm trying to figure out what plugs to buy before I start building the rechargeable power supplies. Normally, devices requiring 12V or higher use a 5.5mm jack with center positive, but this plug is obviously smaller. I have a tremor, so soldering power leads directly to the X400 board would end badly for both me and the board. Do you know the size of the plug I need?

    2. When I assembled it, I used my own brass standoffs. I did this because the nylon standoffs I received are not all the same length. Is this normal? I'd like to switch to the standoffs which came with the board, but I'm mystified by the mismatched lengths. How will using these nylon standoffs keep the board level? Which sizes go where? Am I missing something?

    3. Also, you have an extra editing step in the written instructions which isn't in the video. (/etc/modprobe.d/raspi-blacklist.conf ...) In addition, PeterC288 posted a set of lines in the comments to add to step 2 without needing step 3 and 4. As I'm a total noob, I'm wondering which instructions will give the best result for my build. I'm also worried about whether the changes will break any of the other random tweaks I made already.

    Thanks for the great video/write up and any help you can offer!



    Question 1 year ago on Step 4

    When I follow your instructions to my pi, when reboot, an error appear that the modules can not be loaded, are there missing the bcm2708 driver ?


    Reply 1 year ago

    What amperage?

    Did you ever try to use the outputs for passive boxes?


    2 years ago

    HOw does this work with OSMC 2017.02.02 release? there is no /etc/boot.txt file.

    1 reply

    Reply 2 years ago

    Hello, I'm not sure I haven't tried it. But the retrosmc community should be coming up with a solution soon


    2 years ago

    Step 2:

    dtparam=audio=off #disable Raspberry onboard audio

    dtoverlay=iqaudio-dacplus #enable X400 audio

    dtoverlay=lirc-rpi,gpio_in_pin=17 #enable X400 IR receiver

    Steps 3 and 4 are not needed for Raspbian Jessie


    2 years ago

    The video does a decent job of explaining what the X400 is, however much of that explanation should also be in an introduction to this instructable. Things that even the video is missing include, "Why are you using a Yellow RCA jack for Left Audio, and a White one for Right?" "There is a volume control next to the RCA jacks, are the RCA jacks outputting line level outputs, or speaker level outputs? Does the volume control affect Line Level outputs, or only the screw down terminals on the far side of the board?"

    I'd personally look at getting one if it had audio capture capabilities, as I would think that a RPi based audio recorder would be a great tool to have so that I'm not trying to capture audio on a device that's expecting me to speak into the microphone of a phone. Sure I can get stand alone audio recorders and voice recorders, but with this I could subsequently edit the audio right on the device, and I wouldn't have to be concerned about the prospect of some nosey editor calling the phone I'm using to record an interview in the middle of the recording.

    The other use case I have for something like this is as an audio io device for a ham radio repeater. But as far as I can tell, the designers of this device wanted another Audio output device that won't work as well as feeding HDMI audio into a decent TV or stereo system that will accept that as a source.

    1 reply

    Reply 2 years ago

    Hello, thank you for the comment. The RCA jack isn't a standard jack it has weird colors so i just connected them the right way to the AMP running my whole house audio. The volume control controls every audio output on the board. And also, I like your ideas to use the board with.


    2 years ago

    I see no description or specifications about this board here or in the link provided. Did I miss that somewhere?

    Clearly it outputs audio signals, but what is the source of that sound? What is the power output? Frequency response?

    There are certainly much cheaper audio amplifier boards. What does this have to offer aside from fitting nicely on the Pi?

    1 reply

    Reply 2 years ago

    Hello, sorry about this. It is an SPI audio driver for the rasperrypi. You can find more here,


    2 years ago

    I've got one I must use to use with Volumio, you got me the kick to start doing my project. Thanks

    1 reply

    2 years ago

    Alright I'll bite - what does a Supstronics X400 Expansion Board do?

    3 replies

    Reply 2 years ago

    I'm wondering the same thing! It appears to do something with grammer and punctuation.


    Reply 2 years ago

    Yes it is, it is a spi audio card


    Reply 2 years ago

    looks like some kind of a "digital audio card" for the Raspberry Pi :)


    Cool. I hadn't heard about the supstronics board. I might have to try this out with my Raspberry Pi.