DIY: Chromecast Audio Box with Amplifier

4 min readJan 12, 2016

When the news came out that the Cast family was going to have the “Audio” vinyl-shaped Chromecast, as a music lover I immediately wanted to purchase one to make my experience much smarter. Since throwing money at the screen apparently didn’t make the trick, I started to figure out what my setup would become.

Once upon a time.

I currently own a quite old Sony MCH-BX2 HiFi system, fully featured with a — broken — 3-slot CD reader, the most useless 2-slot tape reader, an analogic radio and two good speakers (6 ohm). Since the beast is much larger than an ATX case, attaching my future Chromecast Audio to it wouldn’t have made it smaller nor nicer: it would have just added a whole new layer of cables to my already messed-up shelf (hello blue Android).

Basically, I would have used my stereo just as an amplifier. Not that smart after all, right?

So why not getting rid of the HiFi body while still using the same speakers? Turns out I need an amplifier for that.

The search for a compact amplifier.

Searching for audio amplifiers on Amazon resulted in a quite nice outcome: a very small audio amplifier board (less than 11€ or 9£) with minimum specs:

2 channels (15W each)
3.5mm AUX input
volume handle
a nice blue LED
damn cheap

The thing is 50mm for each side — tops — so it made the perfect candidate to replace my obsolete system.

All I needed was some kind of box to put it into in order to avoid false contacts (and possibly fires, LOL).

So there is this little 3D printer at work that nobody ever uses, and it feels lonely and unimportant… Let’s fix this.

Cables, adaptors, (basic) 3D craftsmanship, something, something.

The smaller components for the box were purchased from RS Components:

Now, having already practiced with Google (now Trimble) Sketchup in my 2011 VG-development course at uni, I summoned it back to see if I could remember the minimum tricks and build a decent amplifier/Chromecast box.

After a few hours of failed attempts and cursing while trying to understand how to build solid objects, I came up with a decent box for my amplifier, with a nice tailored slot for the Chromecast Audio:

Pro-tip: Sketchup supports printing on paper in scale, just select “Camera → Parallel Projection”, then in the “File →Print” screen de-select “Use model extents” and set a 1:1 printout/Sketchup ratio. It will greatly help you test spacing and holes on paper, that is much cheaper than using your 3D printer to make time-consuming prototypes.

Ta-dah!

After 18 hours of 3D-printing (the model might have needed some tiny little optimizations here and there), both the box and the cover were ready for being assembled (drum roll):