Hi, i have just installed in my house 8 cameras, im getting blacklines and some interference using a 8ch dahua dvr with 8 12v cameras all of them have IR.
i currently use this psu:
9 Way/Port 10 Amp 12V CCTV PSU
all my cameras are conected there i use for positive blue/green wires and for negative white green/ white blue
i connect the PSU to my UPS APC
here i attached a image showing the black lines: http://imgur.com/a/JHcEW
Its strange that when i just connect one camera to the PSU it works good i see no interference right away after i connect the second one then i see interference and black lines.