Latest project in the category "Is it actually useful or just an elaborate #shitpost?": #USB2Speakon!
It's a fully self-contained, USB-C-powered, 2-channel DAC + 5W Class-D amplifier inside a #Speakon connector.
Use it to connect your phone / laptop to any passive loudspeaker and enjoy surprisingly loud music (probably enough to host a room party)
(GitHub link for the interested: https://github.com/RainbowLabsDE/USB2Speakon )
Video of it in action and build log below:
Here is a demo video showing the #USB2Speakon in use.
I'm not sure if the camera microphone captures it accurately, but it's _surprisingly_ loud :D
(I expected around "room volume" at most)
Build log thread coming soon™
*insert standard run-of-the-mill #PCB assembly steps here*
Paste, place, reflow the one side.
Solder the other side by hand (because I didn't have a hot-air station at home and was impatient).
After a few design iterations, I had a working design for a shell that securely holds the #USB2Speakon PCB in the back of the plug.
But I had to relocate the bodged on crystal to the other PCB side, so it would fit inside.
The shell fits snugly and keeps everything together even without the outer housing screwed on.
I also bodged on a 470uF capacitor as a tiny energy buffer, I think it helped a bit with clipping, but obv. not too much.
And with that the first prototype was done™
@LeoDJ
Thats a pretty interesting project, except that i miss coils for an PWM smoothing reconstruction filter, that the speaker cables do not act as unintentional transmitting antennas
My question is, is this chip also able to run on an traditional USB 2 connection that has only 5V available for data, plus an 12V or 19V supply for Power?
@patagona
Correct.
@Laberpferd
Also as a shitpost, I wasn't very concerned about EMI.
Additionally, the amp chip's datasheet (TPA2012) claims it doesn't need filters for its operation and only recommends small SMD ferrite beads if you're concerned about EMI :D
Also, when only one speaker is connected, you basically don't have any speaker cabling ^^
Sorry, please dont take this in any way as arrogant or an aggression, im not sure how to translate that "smooth" into english language
What i technically mean is that chips advertised as "Filterless" saying they require "only a ferrite bead" do this in the context of local speakers with only few cm of wire length and often also case structures acting as kind of faraday cage shield
Its hidden in the small print that things are different when remote speakers can be connected
@Laberpferd
Oh yeah, absolutely.
Didn't take it as arrogant or aggressive, I hope I didn't come across like that either, I struggle with the same problem ^^
@LeoDJ are there crystals in 3.2x2.5mm available for 6 MHz at all? I found that even 8 MHz is rare at this size and the slower the harder they are to find.
Maybe change to oscillators instead of passive crystals, there you have more options in small size, but at a slightly higher cost.
@electronic_eel
Yup, that's exactly what I've noticed too.
I didn't put much effort into the initial search. I saw LCSC had one in that form factor and that was that.
When the wrong one arrived, I thought: "Easy, I'll just look one up on Mouser / Digikey", but couldn't find one there either.
I also came to the conclusion that a crystal in that frequency probably is simply too big for that housing size.
v0.2 will feature an oscillator.
LeoDJ
Laberpferd
patagona
Electronic Eel
adorfer