Hi Prithul,
I believe the answer you are looking for is here:
"http://electronics-lab.com/community/index.php?/topic/29563-0-30v-stabilized-power-supply/&page=84"
audioguru: Post August 31, 2014
A bit more was mentioned on page 87
Please open a new thread if you want to find out more, as this thread is for completed projects. Thanks