I have this Audio DAC board: https://www.banggood.com/PCM5102PCM5102A-DAC-Decoder-Board-I2S-32Bit-384K-For-Raspberry-Pi-Red-Core-Player-p-1259752.html?rmmds=myorder&cur_warehouse=CN

I drive it from an ESP32 via I2S which is working wonderfully thanks to this library. The problem is, the audio output is really quiet. I want to drive the speakers louder.

I have an LM380N(datasheet) which I believe is the right chip to increase the power going out to the speakers, but I am not sure where on this board to 'tap into' in order to drive the LM380N correctly. I presume I cannot feed the LM380N my I2S signal, so where in the chain will the LM380N sit, and how can feed it the correct input / outputs.

Any advice on what to do here?

  • \$\begingroup\$ You need to link to the datasheet that shows the pinout for the device. You've posted to an ad and that link will die in time rendering your question useless to future readers. If you can post an image in your question that would be even better. \$\endgroup\$ – Transistor Mar 3 '18 at 15:20
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    \$\begingroup\$ The LM380N is a very old mono audio amplifier IC. I don't think that's the right IC to amplify two channels of stereo. Your board probably outputs line level signals, so you'd feed in those to the analog inputs. I'd recommend going to TI's website, and look for simple stereo amplifier ICs, and pick one that has a datasheet that comes with an example circuit and build that. \$\endgroup\$ – Marcus Müller Mar 3 '18 at 15:21
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    \$\begingroup\$ Instead of using the LM380 (which can surely work but it is a hassle if you do not have a suitable PCB for it), why not get a ready made audio amplifier module like: banggood.com/… \$\endgroup\$ – Bimpelrekkie Mar 3 '18 at 15:58

A little digging around will tell you that the audio outputs of the DAC board are "line level" and not intended for speakers: -

enter image description here

I am not sure where on this board to 'tap into' in order to drive the LM380N correctly.

You connect your audio amplifier's input to the "gold" RCA phono jacks at the top left of the picture above.

so where in the chain will the LM380N sit, and how can feed it the correct input / outputs.

The output connects to your speaker as shown below: -

enter image description here

And your input connects to the gold phono output left or right. You'll need two LM380 chips for stereo.

  • \$\begingroup\$ Andy what a fantastic answer, thank you for the time this has taken you. I assume I would cut the phono cable....then I would have 2 wires, ground and signal. I assume signal comes from the pin of the phono, as the ring is connected to ground...I think. I would wire that pin cable up to pin 2 on your schema? \$\endgroup\$ – RenegadeAndy Mar 4 '18 at 16:35
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    \$\begingroup\$ "cut the phono cable" - I'd just buy a phono plug and wire it up. Of course you can cut the cable! Signal = pin, yes. Pin 2 is the input ! \$\endgroup\$ – Andy aka Mar 4 '18 at 16:37
  • \$\begingroup\$ I built this circuit today and note that the audio is definitely louder. I also noticed that audio quality has SIGNIFICANTLY dropped. I didn't have any 220uF capacitors around, so do not have them in my circuit, but would adding these really improve the audio output that significantly? \$\endgroup\$ – RenegadeAndy Mar 8 '18 at 22:13
  • \$\begingroup\$ I have no idea what you might have used in place of capacitors but if you replaced C2 with something then what was it. Ditto C1. \$\endgroup\$ – Andy aka Mar 8 '18 at 22:21
  • \$\begingroup\$ The circuit is exactly as you made, except without C1 and C2. What would the result of that be? What I am seeing? \$\endgroup\$ – RenegadeAndy Mar 8 '18 at 22:22

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