- Wed Jul 08, 2015 9:52 am
#183252
I'm trying to build my own simple amp to use with the MP3 trigger.
I'm using this simple TI 386N (currently breadboarded)
http://www.ti.com/lit/ds/symlink/lm386.pdf
http://www.instructables.com/id/LM386-Audio-Amplifier/
The amp works fine plugging in an iPhone or other device, though if the volume is too high there is distortion.
When using the amp with the mp3 trigger, I connect a 3.5mm cable from the mp3 trigger board to a 3.5mm jack on the breadboard. I'm also powering the mp3 board and breadboard with the same 9V battery. However, when I connect everything up, I get a recurring ~1 sec pulse that clicks the speakers and flashes the green LED on the trigger board. How should I wire the two boards together to prevent this from happening? I'm a newbie and don't want to blow the mp3 board. I have a feeling it may be because the battery ground is the same as the GBUF signal ground. How do you separate the signal and power grounds in this scenario? Should there be a common signal ground for pin 2, 3 off the 10k variable resistor, and off the speaker ground? If I were to design a custom PCB, would there need to be two ground planes, one for signal and one for voltage ground?
I'm using this simple TI 386N (currently breadboarded)
http://www.ti.com/lit/ds/symlink/lm386.pdf
http://www.instructables.com/id/LM386-Audio-Amplifier/
The amp works fine plugging in an iPhone or other device, though if the volume is too high there is distortion.
When using the amp with the mp3 trigger, I connect a 3.5mm cable from the mp3 trigger board to a 3.5mm jack on the breadboard. I'm also powering the mp3 board and breadboard with the same 9V battery. However, when I connect everything up, I get a recurring ~1 sec pulse that clicks the speakers and flashes the green LED on the trigger board. How should I wire the two boards together to prevent this from happening? I'm a newbie and don't want to blow the mp3 board. I have a feeling it may be because the battery ground is the same as the GBUF signal ground. How do you separate the signal and power grounds in this scenario? Should there be a common signal ground for pin 2, 3 off the 10k variable resistor, and off the speaker ground? If I were to design a custom PCB, would there need to be two ground planes, one for signal and one for voltage ground?