Hantek DSO5102P D/C measurements.

[chinoy]

Working on discrete voltage regulators and power supply units for audio.

I spent a few weeks trying to build a clean PSU regulated circuit for my pre-amp.
After I figured something was wrong and Ive been chasing my tail. For a few weeks.

Decided to test the scope on a battery. And when I saw the same noise when measuring a bat. Figured its an issue with the scope.
I have a new Hantek DSO5102P (Did not upgrade the firmware / hack).

My problem is I am seeing a 600 millivolt peak to peak when measuring a bat. So the logic of trying to build a clean d/c power supply from audio hits a brick wall here.

What am I doing wrong ?. Unit has been self calibrated multiple times. Probes have been  calibrated multiple times.
I have tried auto set. Manual set. Still I see this peak to peak no matter what bat I try with.

Im thinking I should dig up my old Fluke Scope and see if it reports the same problem.
I have tried with lead acid bat, li-ion bats. No matter what I try. Im seeing this large peak to peak values.

Any tips on how to setup the scope to measure d/c noise. And what is acceptable peak to peak on a d/c line.
Also  if you have any circuits for a discreet 7812 / 7912.
I will try to take some pictures next time Im at the workshop. 

I read on another post to set the signal to a/c if set to a/c this is the results i get.
Note the peak to peak numbers. 
DUT= Li-Ion Bat.
Pic 1 is the result I get if I  click on auto set.

Pic 2 is the result I get if I set coupling to a/c

Video is the result if I set to d/c with 1 volt and I spend a lot of time scrolling to get the line visible. Note the peak to peak number jumping and the noise.
My understanding that a bat should not have noise or peak to peak signals. (Ok video not allowed).

[chinoy]

Found this will add more.
https://www.eetimes.com/tips-and-techniques-for-power-supply-noise-measurements/#:~:text=Due%20to%20the%20wide%20bandwidth,illustrate%20later%20in%20an%20example.