i recently built a preamp but one problem is very critical that when i amp connecting microphone to the preamp along with the laptop in charging mode i am getting a very static strong ground loop or hum noise.
Case1- when all things connected just removed charger from laptop noise goes away
case2- when all then are connected just make volume all the way down noise goes away
case3- when all thing connected just mic is removed then all noise goes away
can any one here who can help me i went so many forums but no one able to give me solution which could solve my problem this forum is my last hope https://youtu.be/UgOWNopvzqo open this to see what the noise