Comments: Audio Codec Breakout - WM8960 Hookup Guide
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Is there a reason that we need to supply 3.3V (via the QIIC connector) even though there is a 3.3V regulator on the board? i.e. could we tie Analog and Digital 3.3V supplies together? Thanks!
Great question! One reason we have them separated on the design is so that any noise on the digital 3.3V net won't be present on the AVDD net (thus avoiding any noise entering the audio). The onboard AVDD is produced by a dedicated LDO vreg that can provide a quieter 3.3V supply for the AVDD pin on the codec. You can certainly try using the onboard vregs 3.3V output for both your digital and analog power supplies, but you may experience some noise enter your audio.
Also, AVDD is used to create VMID (inside the codec), so it's nice having a dedicated vreg for this. If you are using another power supply that is also powering other parts of your system, then it may change (droop below 3.3V) when large current surges occur. Again, this may not be an issue (depending on your power source and the vreg), but there is no guarantee it won't have bad effects on your input gains, mic bias, and/or outputs if AVDD isn't rock solid.
Hi, to anyone interested, I've designed a circuit board that connects this Codec to the Sparkfun Thing Plus ESP32. It includes a MIDI interface and a convenient set of pads and header for connecting external controllers. I've also put together a software package for building Audio Effects with this board, with full documentation. Check it all out on my website, https://www.jtalbert.xyz/ESP32/ -- John Talbert, retired electronic music tech
Great projects! Thanks for sharing! I'm curious, what types of audio effects have you been building? (compression? reverb?) Also curious about latency. The reason I ask is that I've been wanting to explore options for a reverb and/or delay to add to my personal-monitoring headphones project. Cheers!
Is there a way to get line level output? If not are there plans to make a version of this that supports line level output? Thank you!
Hi 065, Thanks for asking. Yes, you can connect the HPL and HPR outputs to another sound system as a "line level signal". These will act as your un-balanced (aka "single-ended") line level signal outputs.
Note, it is common practice for a line level output (and some headphone amp outputs) to have output capacitors, however we did not include these on this breakout for optimal frequency response and size constraints. Most sound systems that you would plug into should have input capacitors, so in most cases you won't really need to add capacitors in-series to your signal. However, if you don't know if your downstream device has input capacitors, then you could add some in. Note, they will form an RC filter with the impedance of your downstream devices input, so usually it's a good idea to use large caps (47uF or 100uF), to ensure you still get good bass response.
If you'd like to learn more about the nuances involved with plugging in headphone outputs into line level outputs, then I can recommend searching google for "headphone output as line level". There are lots of great articles on the subject.
One more thought, if you'd like to make it a balanced audio signal (for more immunity to external noise and/or long distance), check out our SparkFun THAT 1646 OutSmarts Breakouts.
Hope this helps and good luck with your audio project! -Pete