Breadboarded it! Had to use a 100uf, 100uf, 10uf, and 10uf in parallel to sub for the 220uf but had all the other components. This really works. I am thinking of using it for a guitar pickup system where I will mount a high quality JLI electret capsule in the body and combine with a piezo pickup. I may tweak the values a bit for better frequency response for guitar and add a volume pot, but thanks so much for this starting point! I am enjoying learning electronics
I really like how you include test points, I'll be building my circuits like that, as I do most of mine on bread board, I have test points everywhere already.
Hi, good job, sir.Congrats I was having trouble with noise (humming) as I did not put the capacitor in the voltage feed. I saw your video and it did help me. I added a 470uF (bigger than the suggested humongous one) and the humming sound went almost off. Thanks a lot for your donation of knowledge
Use decoupling filter to decouple amplifier from power rail. A high pass RC basically. The R is one-tenth of R(c) and C ought to have reactance X(c) of 1/10 of R at the lowest frequency you wish to amplify. Do this and the motor boat sound shall be gone!
Depends on the input impedance of the headphones. Common emitter amplifiers are not suitable for driving low impedance loads directly. Add a common collector stage between this amp and the headphones and this will work.
That's great thank you. Yes I have heard about the need for high impedance headphones but they seem very rare. I've only seen them on very old equipment (but havn't got any!). I'll add another transistor (common copllector) and see if it will work with modern low Z 'phones. Many thanks, Peter@@BalticLab
I just breadboarded your circuit, as you designed it. My condenser mic was a donor from an old telephone answering machine, IIRC. My BJT was a PN2222A. Your circuit works very well. I will use your circuit to create a DIY Decibel Meter with an Arduino. There is lots of code available. The new meter will have to be calibrated. To do that, I will need a reference tone of a known decibel amplitude. Does anyone know a way to create the needed tone? Lots of projects rely on an Android Decibel Meter App, to do a comparison. However, I do not have an Android phone and I am very phone savvy. I do have a laptop and I know about Audacity, but not how to set up the two as the reference. I also have a Rigol Function Generator, if someone can give me the specifications on the tone... 1KHz, at one watt, one foot in front of the speaker = X Decibels?
Does this pre amp invert the ac signal from the electret microphone? If so, will the inverted signal affect the sound output if it was connected to a speaker?
Yes, the signal will be inverted. However, this should not have any audible effects at all. Now that said, the output of the amplifier is fairly high-impedance and is thus not suitable for direct connection to a speaker.
I'm assuming that your mixer has a high input impedance for the baseband audio input, or you're using a buffer like an emitter follower between this preamp and your DBM.
What if I want to make a circut for String instruments which components should I pick!?? Or which changes should I make!?? Just loved your explainations
The amplifier shown in the video works perfectly fine for string instruments, such as a guitar. However, there will be a video showing an improved version soon.
Hi i find your video very interesting i would like to try to build one is there any way you could send me the diagram more in detail im a beginner on this so when reading diagrams i get something and some i steuggle with. I would really apreciate it. Thanks and great video
Hello, thanks for the video.. I have a strange question, wondering how one would use a simple transformer in this design , is it drastically more. Complex?
No, not significantly more complex. Use the secondary coil of the transformer in place of the electret mic and omit the resistor above the electret mic. That's one easy approach.
The biasing point of this amp has been calculated for 9V supply voltage. It might work with 3V but I haven't tested it. If you do end up testing it with 3V, please let us know what your results were.
Hi, I made your circuit and it works. However I'm getting this high frequency noise and humming coming through. I tried what one comment suggested and swapped the 220uF cap with a 47ouF cap, it did not help. Do you have any advice? And to clarify, i'm using a handmade dynamic microphone, and I did remove the 10k resistor for biasing the mic.
How clean is your power-supply? Or does the hum only occur with the microphone attached? Do you have a way of applying a very clean input signal from a signal generator and see if the same effects appear?
This is a very clear explanation but I'm not sure why you say the amplifier will sound 'funny'. Also, what is the gain of this circuit and can it be varied?
hi, thanks for the video. could you put up a schematic if i want to use a dynamic microphone? also all the legs you draw from mic, capacitor and transistor are connected to the negative terminal of the battery?
Input impedance is around 100 kilo-ohms. Reasonable enough. I'll use, potential-divider bias however, for improved thermal stability for Q point. Cool though!
@@awaismushtaq5719 The input impedance is a lot lower than 100K. Less than 10K even. Thermal stability is not really important in small signal amplifiers. If you're really using the majority of the possible output swing or need a lot of headroom to the non-linear edge of the transfer function, that'll become important.
thanks for the video. I am interested in making a microphone for an icom ic-746 radio, using the panasonic wm61a capsule. will the 746 need a preamp for the input or will the inbuilt preamp which is known to be a bit weak do? what about impedance matching between the wm61a and the tranceivers? thankyou, any and all help much appreciated
Can you add a Variable resistor for Mic Gain adjustment? I would like to build this for my TYT TH-7900 2m/44 VHF/UHF radio desk mic which is a TYT also.. Thanks
Sure thing! You could add a potentiometer in the collector of the amplifier; Higher resitance = higher gain, lower resistance = lower gain. However, that also changes the output impedance of the amplifier. Then you could simply add a potentiometer between the output and ground, tap your signal output off the wiper.
I know this video is kind of old, but it's still worth a try asking. What would happen if you place the mic the other way round? I mean, positive end of the mic to GND and negative to 9V. Will it not work? I'm asking because I think I accidentally did that.
Unless it burnt the diaphragm than nothing would be harmed especially if the resistors were in the circuit. If you connect a 9v to the mic straight up it will burn the diaphragm with the coil heating up. Mics work just like a speaker in reverse. A very delicate speaker.. but its possible you boogerd. The mic up.. to tesst it. Hook a 1 μf 10v or higher. Cap and a 10k resisstor and plug it straight into a powered speaker..
PLEASE HELP ME. I used your circuit and it is a good preamplifier but I generated a sine wave then I have transmitted it by using speaker, however at the output of this microphone circuit sine waves looks like a square having distortion around peak values, I think I should change the 220 k resistor, could it be helpful? Or do you have any idea?
Nice video. I like these ahort and simple type videos. But I do have one question: Could you tell me why you chose a 220K ohm pullup resistor on the base? I realize that the bias point is not very important in this circuit and that it will get stabilized due to the feedback from the collector resistor, but I am curious as to the value. Is it simply that it needed to be a reasonably high value and you happened to have 220K resistors in your junk bin, or was there more thought that went into this? Thanks
Not very. On the collector / base resistors a ratio of the DC current gain of the transistor is mildly important. Usually 1:100 with general purpose transistors.
Hello! Man I'm really getting in trouble making the circuit design on eagle. I don't know much about the program. Do you have some files to share with us?
sir, how do I boost the mic audio from this circuit ? and which part I would replace? im using it on my pc for testing purposes. pls dont include mic boost from windows. ty!
You're smart! I have all of the components you have in the video, but could you help me? I want to make an amplifier using BC547(s) for a tiny speaker from a headset so that it is a bit louder. Is that possible?
@@Wolfgang3418 maybe. I'd actually intended to use it as a pre-amp for a summing mixer I'd built. I wasn't getting good volume from the mixer, so I wanted to use this to pump up the volume before sending it to the amplifier. Do have any designs that can perform that function?
Hi Ronnie! May be you are using passive inputs, say 3 channels, each with a potmeter working on one transistor. That's no good. Every input should have a transistor for itself like in this example: easycircuit012.blogspot.com/2012/09/three-channel-audio-mixer-circuit.html As you can see, you can easyly throw out one channel and replace it with the preamp for your mic. See the link in my comment for the voltage the capsule requires. In the circuit by KF5OBS my capsule got 7.2V, far to much for the cz 034 I used. Hope it helps! OOps, my comment seems to be deleted. Why that? The circuit is here: www.pic-upload.de/view-36963733/MicrophonePreamp.jpg.html w
Condenser are other similar type. Electrets have pre-poloarized their capsules, and do not need phantom power. Condensers needs to charge their capsules with +48v phantom.
I wish to see an updated version, please do it!
till date you are one of the best in this video. after 7 years still a competitive one of elaboration
Sir! Hat's off to you! The most clear voice and explanation i have heard on UA-cam for a while.
You Sir, restored my faith in condenser mic! XD
Breadboarded it! Had to use a 100uf, 100uf, 10uf, and 10uf in parallel to sub for the 220uf but had all the other components. This really works. I am thinking of using it for a guitar pickup system where I will mount a high quality JLI electret capsule in the body and combine with a piezo pickup. I may tweak the values a bit for better frequency response for guitar and add a volume pot, but thanks so much for this starting point! I am enjoying learning electronics
I really like how you include test points, I'll be building my circuits like that, as I do most of mine on bread board, I have test points everywhere already.
Very very clear explanation
Can i use this circuit with a piezo disk as a contact mic?
Yes you can. Insert the piezo disc insteadof the microphone and remove the first 10 K Ohm resistor as the piezo disk doesn't need a supply voltage.
Very nice ...works well cristal clear voice ;-)
Thanks, Richard! Glad you enjoyed the video!
You are an amazing teacher
Thank you. Glad you liked it!
@@BalticLabloved it. Can you a video of adc and i2s too? Thanks
I'll put it on a list. My top priority item right now is to redo this video a bit more modern.
@@BalticLab that’ll be great. Appreciate the efforts
Very nice explanation; very clear too; explains at the right pace.
Hi, good job, sir.Congrats
I was having trouble with noise (humming) as I did not put the capacitor in the voltage feed.
I saw your video and it did help me.
I added a 470uF (bigger than the suggested humongous one) and the humming sound went almost off.
Thanks a lot for your donation of knowledge
Use decoupling filter to decouple amplifier from power rail. A high pass RC basically. The R is one-tenth of R(c) and C ought to have reactance X(c) of 1/10 of R at the lowest frequency you wish to amplify. Do this and the motor boat sound shall be gone!
Excellent. Thank you.
Very nice - would that power headphones directly? Trying to make a deaf-aid to hear the television sound more clearly.
Depends on the input impedance of the headphones. Common emitter amplifiers are not suitable for driving low impedance loads directly. Add a common collector stage between this amp and the headphones and this will work.
That's great thank you. Yes I have heard about the need for high impedance headphones but they seem very rare. I've only seen them on very old equipment (but havn't got any!). I'll add another transistor (common copllector) and see if it will work with modern low Z 'phones. Many thanks, Peter@@BalticLab
Thanks for the practical tip about test points.
Excellent thank you. Just what I need, got an electret mic which is too quiet for pc sound card so this is just the job.
Glad I could help!
I just breadboarded your circuit, as you designed it. My condenser mic was a donor from an old telephone answering machine, IIRC. My BJT was a PN2222A. Your circuit works very well. I will use your circuit to create a DIY Decibel Meter with an Arduino. There is lots of code available. The new meter will have to be calibrated. To do that, I will need a reference tone of a known decibel amplitude. Does anyone know a way to create the needed tone? Lots of projects rely on an Android Decibel Meter App, to do a comparison. However, I do not have an Android phone and I am very phone savvy. I do have a laptop and I know about Audacity, but not how to set up the two as the reference. I also have a Rigol Function Generator, if someone can give me the specifications on the tone... 1KHz, at one watt, one foot in front of the speaker = X Decibels?
Is there any way you can post a picture of your breadboard connections?
Very nice. Is this the kind of amplifier that could detect air leaks?
Hmm, don't you need the ultrasound range for that? Not sure if this amp has the necessary frequency response for that.
Does this pre amp invert the ac signal from the electret microphone? If so, will the inverted signal affect the sound output if it was connected to a speaker?
Yes, the signal will be inverted. However, this should not have any audible effects at all. Now that said, the output of the amplifier is fairly high-impedance and is thus not suitable for direct connection to a speaker.
Good simple circuit. You can use BC550 or SS9014 or 2SC2240 or 2SC2458 transistor. Good video
Thanks for the explanation. Can i use this circuit with fantom power from mic mixer without using 9v battery?
Using phantom power from a mixer for this circuit will require a major re-design. So the short answer is: No, not without modifications.
Done, works, thanks, adding more transistors.
Don't just add transistors blindly, try using a V(be) multiplier and a push-pull in final stage to drive speech coil!
Clear and neat. Thanks!
Thanks so much!
Great video l love it thanks for posting..
Thanks, I'll be doing this today.
Great video thank you for posting
I'm assuming that your mixer has a high input impedance for the baseband audio input, or you're using a buffer like an emitter follower between this preamp and your DBM.
What is the gain of this preamp? And how can I calculate it? :) Nice vid
Voltage gain will pretty much be equal to the Gain of the transistor you use.
What if I want to make a circut for String instruments which components should I pick!?? Or which changes should I make!?? Just loved your explainations
The amplifier shown in the video works perfectly fine for string instruments, such as a guitar. However, there will be a video showing an improved version soon.
Hi i find your video very interesting i would like to try to build one is there any way you could send me the diagram more in detail im a beginner on this so when reading diagrams i get something and some i steuggle with. I would really apreciate it. Thanks and great video
Do you have your transistor in backwards? Please advise, thank you, James.
Negative. Else the circuit wouldn't have worked. Well, arguably it might have worked in reverse. But it wasn't though.
Can you explain out cables?
How can I abn tone and gain control to this? Little preamp?
Newbie question: why the output has just one terminal? Where are the positive/negative that I should connect to a jack, for ex. Thank you!
The output is the desired signal, the counter-pin, or reference pin, is ground.
Hey! Thumbs up, and you have a new subscriber. Great vid. I'm building this right now. Thanks.
I'm hoping this will drive the mic on a LED VU meter.
thanks... it's really works fine... very simple circuit..
What kind of capacitors are those square red ones?
If I remember correctly, they're Wima FKP2 capacitors.
Hello, thanks for the video.. I have a strange question, wondering how one would use a simple transformer in this design , is it drastically more. Complex?
No, not significantly more complex. Use the secondary coil of the transformer in place of the electret mic and omit the resistor above the electret mic. That's one easy approach.
Or wait: Did you mean audio input/output transformers or a transformer for the voltage supply?
Did you finish if you I want to watch it
Led's as varicap. Interesting idea.
What is that orange capacitor?
please make it as soon as possible
thanks for sharing this insightful informative video! nice job!
thanks, i build ¡ and yes really work . the pream. gracias amigo saludos desde mexico
De nada!
can be run this circuit from 3v ??
The biasing point of this amp has been calculated for 9V supply voltage. It might work with 3V but I haven't tested it. If you do end up testing it with 3V, please let us know what your results were.
Can we use electrolytic capacitor for coupling cap? And what polarity sud the capacitor be?
why is your circuit board of SSB is look like that?. what is the reason and purpose or advantage?. for low noise?
Hi, I made your circuit and it works. However I'm getting this high frequency noise and humming coming through. I tried what one comment suggested and swapped the 220uF cap with a 47ouF cap, it did not help. Do you have any advice? And to clarify, i'm using a handmade dynamic microphone, and I did remove the 10k resistor for biasing the mic.
How clean is your power-supply? Or does the hum only occur with the microphone attached? Do you have a way of applying a very clean input signal from a signal generator and see if the same effects appear?
This is a very clear explanation but I'm not sure why you say the amplifier will sound 'funny'. Also, what is the gain of this circuit and can it be varied?
thanks a lot 👌
hi, thanks for the video.
could you put up a schematic if i want to use a dynamic microphone?
also all the legs you draw from mic, capacitor and transistor are connected to the negative terminal of the battery?
Cool, can't wait to see the LEDs in action.
Thanks for sharing.
Input impedance is around 100 kilo-ohms. Reasonable enough. I'll use, potential-divider bias however, for improved thermal stability for Q point. Cool though!
@@awaismushtaq5719 The input impedance is a lot lower than 100K. Less than 10K even. Thermal stability is not really important in small signal amplifiers. If you're really using the majority of the possible output swing or need a lot of headroom to the non-linear edge of the transfer function, that'll become important.
im thinking about common base amplifier as another way of making mic amp.
thanks for the video.
I am interested in making a microphone for an icom ic-746 radio, using the panasonic wm61a capsule. will the 746 need a preamp for the input or will the inbuilt preamp which is known to be a bit weak do? what about impedance matching between the wm61a and the tranceivers? thankyou, any and all help much appreciated
Can anyone please tell me which resistor can change the gain or the output level of the pre-amp?
Can you add a Variable resistor for Mic Gain adjustment? I would like to build this for my TYT TH-7900 2m/44 VHF/UHF radio desk mic which is a TYT also.. Thanks
Sure thing! You could add a potentiometer in the collector of the amplifier; Higher resitance = higher gain, lower resistance = lower gain. However, that also changes the output impedance of the amplifier. Then you could simply add a potentiometer between the output and ground, tap your signal output off the wiper.
Thank you!
I know this video is kind of old, but it's still worth a try asking. What would happen if you place the mic the other way round? I mean, positive end of the mic to GND and negative to 9V. Will it not work? I'm asking because I think I accidentally did that.
Would appreciate if anyone seeing this post answered
if you have more just switch it out. A while back I made the same mistake, and I after correcting it, it seemed to work just fine.
Not on electret mics
Unless it burnt the diaphragm than nothing would be harmed especially if the resistors were in the circuit. If you connect a 9v to the mic straight up it will burn the diaphragm with the coil heating up. Mics work just like a speaker in reverse. A very delicate speaker.. but its possible you boogerd. The mic up.. to tesst it. Hook a 1 μf 10v or higher. Cap and a 10k resisstor and plug it straight into a powered speaker..
electret mic's are biased.. polarity must respect
How can i maker phantom power supply for condenser microphone?
Can a resistor be used in the circuit with a switch as a pad?
i have built this and its not working. what might be the problem?
I can't possibly know. I'd need a very precise description of what you did and how the error manifests itself.
Can you make a tutorial where the power and the mic input are combined in one usb cable
what is the code of npn amp?
Pretty much any NPN Transistor will work... BC548, 2N3904...
FOR SOME REASON I GOT A LOT OF NOISE WHEN I CONNECT SUCH CIRCUIT TO AND ONE MOSFET AUDIO AMP ........ HELP PLEASE .......
can it be use for song recording?
PLEASE HELP ME. I used your circuit and it is a good preamplifier but I generated a sine wave then I have transmitted it by using speaker, however at the output of this microphone circuit sine waves looks like a square having distortion around peak values, I think I should change the 220 k resistor, could it be helpful? Or do you have any idea?
dose it works with 5V power?
Yes
Nice video. I like these ahort and simple type videos.
But I do have one question: Could you tell me why you chose a 220K ohm pullup resistor on the base? I realize that the bias point is not very important in this circuit and that it will get stabilized due to the feedback from the collector resistor, but I am curious as to the value. Is it simply that it needed to be a reasonably high value and you happened to have 220K resistors in your junk bin, or was there more thought that went into this?
Thanks
Adding test points is a really good idea.
how important are the component values? what kind of tolerance can I have on each resistor? (too poor to buy parts, only salvage.)
Not very. On the collector / base resistors a ratio of the DC current gain of the transistor is mildly important. Usually 1:100 with general purpose transistors.
We need a LINK to the SCHEMATIC, and parts list, PLEASE.
baltic-lab.com/2024/12/simple-microphone-preamplifier/
isnt the mic is polarized and what is the output voltage of the thing?
the one connected to the metal case is the negative
i am make that circuit same as you show in the board and i power that with 9v battery but its not working how to fix the problem
check the circuit and microphone , still have problem then change the transistor.
My good sir, 2024 remake with a side of schematic please
Duly noted!
can we connect output and ground to a speaker
+Yash Ashra Sure but I doubt it has enough drive for that.
Hello!
Man I'm really getting in trouble making the circuit design on eagle. I don't know much about the program. Do you have some files to share with us?
sir, how do I boost the mic audio from this circuit ? and which part I would replace? im using it on my pc for testing purposes. pls dont include mic boost from windows. ty!
You can use two stages of this amplifier in series.
bro I think that shall work but should also mention the circuit diagram and the parts list in the video description
Can you tell me exactly what capacitor is this 0.1 uf I mean polyester or what? ana also what volt?
Did you watch any of the fucking video before you asked your stupid godamn question?
polyester 104 15V
does it work with piezo disk?
Wadi Ghassen have you got the answer?
Does it?
@@sanjaybali4092 did u try?
@@lordrahulcool yes I try it with Piezo. But Its Working is fine with mike. With piezo its output is not enough.
@@sanjaybali4092 what wud you suggest me for piezo pre amp to remove tinny sound?
Schematic please
nice it can be working
You're smart! I have all of the components you have in the video, but could you help me? I want to make an amplifier using BC547(s) for a tiny speaker from a headset so that it is a bit louder. Is that possible?
2024 remake plsss cause i'm trying to do it but I keep failing D:
its good but if show me another side of board its pretty better
your the man
2024 Remake
:)
Noted
2024 Remake & Schematic
Duly noted 😀
We need you to make a follow up video showing how to turn this into an actual universal microphone preamp.
What characteristics would you like to see in a truly universal mic amp?
I wonder where I went wrong with this. I got nothing. Volume was lower actually.
Hi! Let me guess: You have the wrong type of mic inserted. What you need is an electrolytic / condenser mic.
@@Wolfgang3418 maybe.
I'd actually intended to use it as a pre-amp for a summing mixer I'd built. I wasn't getting good volume from the mixer, so I wanted to use this to pump up the volume before sending it to the amplifier.
Do have any designs that can perform that function?
Hi Ronnie! May be you are using passive inputs, say 3 channels, each with a potmeter working on one transistor. That's no good. Every input should have a transistor for itself like in this example: easycircuit012.blogspot.com/2012/09/three-channel-audio-mixer-circuit.html As you can see, you can easyly throw out one channel and replace it with the preamp for your mic. See the link in my comment for the voltage the capsule requires. In the circuit by KF5OBS my capsule got 7.2V, far to much for the cz 034 I used. Hope it helps!
OOps, my comment seems to be deleted. Why that? The circuit is here: www.pic-upload.de/view-36963733/MicrophonePreamp.jpg.html
w
@@Wolfgang3418 Thanks. Let me have a look at the circuit.
"electrolytic" microphone? lol it's "electret" microphone.
Ha-ha-ha
As long as the audience can understand, its okay
We call it condenser mic. Different regions/countries use different name for the same thing.
Condenser are other similar type. Electrets have pre-poloarized their capsules, and do not need phantom power. Condensers needs to charge their capsules with +48v phantom.
How can i make phantom power supply for condensor microphone...?
Not electret its electrod you fool
2024 remake
Noted :-)
"Schematics" Please . ..
draw them out!
Please brother, we need mathematical operations.
Components list??
why didnt you put a high pass filter on the emitter?
2024 remake