when laptop is connected to the charger and just only preamp is connected to the laptop no problem here is the screen shot

now every thing is same just mic connected to preamp see the problem


now every thing is same as above just remove the charger from laptop

schematic that i used is attached below

can some body give me a correct and full proof solution for my problem

 

Does the noise decrease as you move the microphone farther away from the charger? The circuit may be acting as an antenna and picking up interference from the switching power supply.

Also, is your 9V source sharing a ground with the laptop? Be careful if the 9V source is not isolated - you do not want to connect power supply grounds until you verify there is no current path. I'd use a 9V battery for testing first and only switch to a plugged-in source once things were working with a battery.

 

Does the noise decrease as you move the microphone farther away from the charger? The circuit may be acting as an antenna and picking up interference from the switching power supply.

Also, is your 9V source sharing a ground with the laptop? Be careful if the 9V source is not isolated - you do not want to connect power supply grounds until you verify there is no current path. I'd use a 9V battery for testing first and only switch to a plugged-in source once things were working with a battery.

No Sir I Just Tried It is Not Decreasing Problem Remains the same
When used my mic with preamp in desktop same problem occurred
What should I do Sir??

pls find the video of the problem above this is how it sounds like

 

Hello,

What happens when you split R1 into 2 X 4K7 and put a 10 uF capacitor from the middle of the 2 4K7's to ground?

Bertus

 

Hello,

What happens when you split R1 into 2 X 4K7 and put a 10 uF capacitor from the middle of the 2 4K7's to ground?

Bertus

i tried but did not made any difference

Is there anyone One who can solve my Problem Pls help me ????

 

What is your 9V source? Measure the actual voltage being supplied to the 7805 under operation.

Also, try posting a photo of your build and the wiring to the microphone.

 

i am using 9v battery
Actually recently due this ground loop my laptop's left speaker got damaged

 

How do you know that you have a ground loop problem?
What is the quality of the sound from the mic as heard through the speaker?
Have you tried connecting the mic directly to the mic input of the laptop?

btw, 1000μF for C3 is not the right value to use on a three-terminal linear voltage regulator. Check the IC manufacturer's datasheet.

 

How do you know that you have a ground loop problem?
What is the quality of the sound from the mic as heard through the speaker?
Have you tried connecting the mic directly to the mic input of the laptop?

btw, 1000μF for C3 is not the right value to use on a three-terminal linear voltage regulator. Check the IC manufacturer's datasheet.

this is the video link of my problem it may be a ground loop or RF interference
mic sound quality is great when i used it with laptop(not in charging mode) i hv recorded many songs
i hv directly connected the mic to laptop input same issue but much less than with preamp
one more thing is when i move my 10k pot all the way down problem goes away. or if i disconnect the mic from preamp problem also goes away
you Sir Mr.Chips Sir can you help me to fix it????

 

Hello,

What happens when you split R1 into 2 X 4K7 and put a 10 uF capacitor from the middle of the 2 4K7's to ground?

Bertus

Bertus Sir where are You???

 

Hello,

It has already been asked before : post a picture on how all is connected.
It looks like there are some long lines that are picking up the noise.
As @MrChips said, the output capacitor of the LM7805 is not correct:




Bertus

 

Hello,

It has already been asked before : post a picture on how all is connected.
It looks like there are some long lines that are picking up the noise.
As @MrChips said, the output capacitor of the LM7805 is not correct:

View attachment 167188


Bertus

i hv given both my preamp ciruit one with regulator and another is with regulator both having same issue

 

Hello,

I do not see the microphone itself on the pictures.
Is it connected with a long cable?
Is that cable shielded?

Bertus

 

Hello,

Perhaps the following project might work for you:
http://sound.whsites.net/project93.htm

I have here a single power supply version using a 9 Volts battery:



Bertus

 

Mic is Not Connected And i hv used 2.5 Meters long cable

 

Hello,

Perhaps the following project might work for you:
http://sound.whsites.net/project93.htm

I have here a single power supply version using a 9 Volts battery:

View attachment 167193

Bertus

 

Hello,

I do not see the microphone itself on the pictures.
Is it connected with a long cable?
Is that cable shielded?

Bertus

I HV Posted the microphone wiring pics hv u seen Sir

 

Hello,

As far as I can tell, the used cable is unshielded.
It will pickup noise from its surroundings.

Bertus

 

ok so all the noise not from circuit from the mic wiring right can you tell how a shieled cable loooks like how can i identify

 

Hello,

Here is a page with a picture of a stereo shielded cable.
The black and white threads are the signals, the copper braid is the ground/shield:
https://www.ebay.com/itm/100ft-Microphone-Mic-XLR-1-4-TRS-Raw-Premium-Audio-Cable-8-0mm-Bulk-Cord/111799590770?_trkparms=aid=555018&algo=PL.SIM&ao=1&asc=20131003132420&meid=1fb97d4bed1449c58c7595b8d3c4921a&pid=100005&rk=1&rkt=2&mehot=ag&sd=271463460915&itm=111799590770&_trksid=p2047675.c100005.m1851

Bertus