Audio amps


Oct 29, 2017
I just received a couple prototype audio amplifier boards from JLCPCB. It's a legit miracle, I've soldered and tested them and both of them worked! So I thought I'd share them with you guys.

First, I made them both to fulfill these req's:
  • Analog audio input
  • Analog (potentiometer/volume wheel) volume control
  • Speaker/headphone switch functionality
  • Cheap components readily available from China
  • Simple to solder! DIP chips and nothing in SMD smaller than a 1206.
I selected two Texas Instrument chips, the LM4863 and the TPA6021a4n. Here's the pcb of the latter:

BOM (excluding header connectors):

As you can see, I didn't board mount the headphone and potentiometers since I was planning to have wires to them. It can be easily fixed, I'm sure. I've tried it with a simple 10k potentiometer, and it seems to do the job just fine.

And here's the board for the LM4863:

and the BOM (again excluding JST-XH header connectors):

Both board layouts are available here:

Now, I've only given them bare minimum testing to confirm they make sounds and switch output properly, so if you want your own, check them for errors first or blame yourself later. Now I know there are other, newer, better, fancier chips out there, but these ones, I'd say, are pretty good choices if you want a cheaper-but-still-useful design and don't trust your soldering skills more than you have to.

The 6021a4n is a much, much more audiophile friendly chip, and is the one I'd recommend unless on you're a very tight budget. The LM4863 does a good job with headphones, but you'll have a harder job getting a good sound out of speakers with them. On the other hand, they're like $0.10 each from china, while the 6021 will cost you at least 10-20 times that.

I used tantalum caps since I think they're neat. You may shave off a few pennies substituting them for aluminium caps, or if you want to use stuff you got lying around. These chips aren't very particular with stuff like that.

Feel free to comment on the designs, I know basically nothing about this stuff and they're my first shots at PCB design. Anyway I thought I'd share the designs since they work(!) and I couldn't find any for myself when I looked for stuff like this earlier. They might even help somebody, who knows.
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