Tuesday, 10 December 2013

Dynamic Mic Pre-Amplifier

This is a latest design of a Dynamic Mic Pre - Amplifier and it works 100%. I also posted a video on YouTube about its working and how i build it.
It is based on a single transistor that is an NPN  BJT transistor C9013. There are many other transistor what you will find in wide variety but this has some different feature. I have tested 2N3904, 2N2222, KT312, C945 and BC547 but all of them don't works like this one. And this transistor gives the good gain for the Dynamic Microphones. 
Here is its circuit schematic i tried to make it work with 5v you can also use a 9v battery but connect positive of your battery and positive of pre-amp through a 100 Ohm resistor (0.25 W) You'll be able to make it work with 9v also. Also by using some circuits like voltage drop etc you can also use it with power supplies of other voltages. 

This schematic is the our basic schematic and it is just a pre-amp for the dynamic microphones. This also works well with long ribbon microphones or other that has impedance about 700 Ohm. It is not suitable for the high impedance like piezo-pickups and crystal microphones. I'll post circuits for Preamp of Piezo Pickups and crystals microphones later.



Here is its little modification. I just added a potentiometer to it. As you can see clearly that the output of our basic circuit is just connected to the wiper of 10k potentiometer and left end is connected to ground and one end is for the Output.


Remember that use battery if you don't know about how to clean a supply, i'll make a post about it also very soon.
Here are the stuff required for this pre-amp:
  • 1 - Resistor 220K Ohm
  • 1 - Resistor 330 Ohm
  • 1 - Resistor  1K Ohm
  • 2 - Capacitors 10uf    (Usually they comes with 50v but you can use a 16v or 25v cap also)
  • 1 - Capacitor    100uf  (220uf or 470uf will also work, but voltage should be at least 25v)
  • 1 - Toogle Switch
  • 1 - BJT Transistor C9013 (Here is its date sheet)
  • 1 - Potentiometer   10K Ohm   [Linear or audio both will work  (Optional)]
  • 1 - LED    (Optional it isn't necessary) 


 So what do you think about it..?? Just create and see how good it works. Also you can give it a cool look. You can create it in a beautiful way. If you still have a problem then check out this video tutorial it tells about its working and how i created it and how it looks like. And you'll see the gain in the software "Audacity" which is a freeware wonderful software. You can also download it but it is for windows pc only.

If you are a beginner then make sure you have checked our latest tab named "Beginners" there are many useful information on this tab about how to read symbol what is resistor and capacitor looks like etc.

So here is the video tutorial of this Pre-Amp
 The audio in the video is recorded by this pre-amp. Specially listen to the closing speech in this video.
I know someone who will think to create this pre-amp will also think for what purpose it is suitable. Well if you have a "Ultra Clean Power Supply" and you have no noise you can use it for any purpose like "Recording Songs", "Recording Instruments with dynamic mic" "Live Performances", "Live Broadcast". And i am you're gonna love its output. Well i can add more things in it like equalizer etc but these things are also available in the PC suits so creating them is a useless thing. Well i will take a look on it.

And HEY...!!! Don't forget to give me your feedback. You are free to comment here without signing up of logging in. Also use my contact form to send me E-mails directly. 

12 comments:

  1. hi i created your dynamic mic preamp and i hear a beep tone still..i checked my connection twice please help me...????????/? reply fast...

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    Replies
    1. Hi there ! I think you're not using a clean dc power supply. So connect a 100 Ohm resistor at +5v and supply positive wire in series.

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    2. If you use our DC noise filter circuit you'll not hear that beep. And also Sam Tech Pro is right that if you put a 100 ohm resistor before +5v it will become a filter circuit too with a capacitor 220uf. Well the best way is to build your own DC noise filter that will help you a lot for other audio materials too.
      (Admin)

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    3. Oh thanks STP i fixed it using 100R resistor.... its working perrrfeeeccccttt.........!!!

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  2. Awesome i love the design. can i use a chargeable battery of 9v in series with 100 Ohm resistor..!!

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    Replies
    1. Yes you are ready to go .Good Luck :)

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  3. This is Harry from Hong Kong. I have built one and it works like a charm. Thank you for your excellent design!

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    Replies
    1. Hi Harry Thank you for trying it i am glad that its working for you. Have a wonderful day..!! Keep in touch...!!
      (Admin)

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  4. Sir i want to use it as studio vocal recording preamp i made it works good but i need more gain with lowest noise possible can i use darlington pair(two c9013 mic)to gain ...

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    Replies
    1. yes you can use pair to make the gain higher. But at the output of first stage you need to add a capacitor 10uf and resistor of 4.7k in-series that will be then connected to the bass of the second stage.

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  5. Hi, can this device connect to a 5.1 or 2.1 home theater subwoofer

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  6. yes you can connect it to any amplifier or hometheater. But it can't power speakers directly coz its a preamp with little gain that boost the low signals like microphone etc.

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