Chopsticks
Active member
Hello Guys!
We're busy with a project including audio and recording, we are using the Teensy 3.2 and the Audio Board with a 20W amplifier. We are using the microphone input (not de line in). to record voices. The microphone we use is a Electret Microphone from Adafruit, also we can connect (by-pass) this microphone by using the microphone on a headphone with a jack-plug.
important to know is that we designed a new PCB including the Teensy, audio, SD and Amplifier.
At first we were using a power supply (tenma 72-10495) connecting to the Board. While recording we didn't hear any noise at all. As soon we connected a seperate voltage supply (just a simple wall adapter), we get this 50Hz noise when we are recording.
View attachment storing_50Hzbrom.zip
Now we are wondering what causes this, we've seen information about ground loops but i don't know if that's the problem.
I have to say, we tested several adapters and with some of them the noise was reduced quite a bit.
Are we doing something wrong with the grounding? When we just play simple audio files we don't hear any noise btw.
Hope you could help us.
Chopsticks.
We're busy with a project including audio and recording, we are using the Teensy 3.2 and the Audio Board with a 20W amplifier. We are using the microphone input (not de line in). to record voices. The microphone we use is a Electret Microphone from Adafruit, also we can connect (by-pass) this microphone by using the microphone on a headphone with a jack-plug.
important to know is that we designed a new PCB including the Teensy, audio, SD and Amplifier.
At first we were using a power supply (tenma 72-10495) connecting to the Board. While recording we didn't hear any noise at all. As soon we connected a seperate voltage supply (just a simple wall adapter), we get this 50Hz noise when we are recording.
View attachment storing_50Hzbrom.zip
Now we are wondering what causes this, we've seen information about ground loops but i don't know if that's the problem.
I have to say, we tested several adapters and with some of them the noise was reduced quite a bit.
Are we doing something wrong with the grounding? When we just play simple audio files we don't hear any noise btw.
Hope you could help us.
Chopsticks.
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