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MH-M18/M28/M38 Bluetooth audio receiver/amplifier tear down

Published: 09 October 2021
Last updated: 05 January 2023
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The MH-M38 is a stereo audio receiver with loudspeaker outputs which can play music from a smartphone wireless via Bluetooth.

MH M38 Bluetooth audio receiver circuit redesignedMH M38 Bluetooth audio receiver circuit redesigned

Because I wanted to miniaturize this module for my electronic larynx, I have redesigned it.
You can download the newest version of the schematic at GitHub.
MH M38MH M38 Bluetooth audio receiver schematicMH M38MH M38 Bluetooth audio receiver schematic
Questions about the design

  1. The resistor R2 is superfluous, I dont know why it is used.
  2. The TC8871 can be turned off by making pin 1 high. These 2 pins are connected to the MH-M38 pin 18, but this is constant 0V. So it makes no sense.

MH-M38 tear down in progressMH-M38 tear down in progress

 

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