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The Learning Circuit 69: OpAmps Project: Build an Amplified Stereo Mic Kit

OpAmps Project: Build an Amplified Stereo Mic Kit

The Learning Circuit | element14 presents |  Project Videos

 

 

In the previous lesson, Karen talked about how op amps work and the many ways they can be used. In this episode, Karen assembles the Velleman MK136, Super Stereo Ear Kit. This kit uses a NE5532 Op Amp to boost the audio input from two onboard microphones to an audio output jack. While a speaker is not included in the kit, there is a potentiometer that acts as volume control. Follow along as Karen walks you through soldering the kit together and then see it in action!

 

Bill of Material:

 

Product Name Manufacturer Quantity Buy KitBuy Kit
MK136 -Hobby Project Kit, Super Stereo Ear, Stereo Audio Amplifier, 2 x Microphones Velleman 1 Buy NowBuy Now
DSOX1204G -Digital Oscilloscope, InfiniiVision 1000 X-Series, 4 Channel, 70 MHz, 2 GSPS, 1 Mpts, 5 ns Keysight 1 Buy NowBuy Now
AA Batteries Pro Elec 3 Buy NowBuy Now

 

Additional Parts:

 

Product Name

Speaker with 3.5mm audio cable

 



Anonymous
  • in reply to jw0752

    That's so cool! Thanks for sharing.

  • Hi Karen,

     

    Thanks for doing these learning circuits. I don't have a good application right now for a stereo microphone amplifier but not lacking for extra time while isolating I thought it would be fun to take the circuit and bread board it. I did not have the same Op Amp that you used but this application isn't very specific so I was able to get good results with a TL 082 Op Amp. Here is a picture of my experiment and a photo of the input and output on my oscilloscope. For input signal to the mics I used a small piezo buzzer.

     

     

    I was able to get a gain of about 35. I used ear buds so I didn't have any problems with feed back. All together it was a fun evening.

     

    John

  • Interesting kit.

     

    You could run the output into a microcontroller and use signal analysis to determine the direction of the sound.

     

    DAB