power brick introducing hum

[garfo]

I have bought a Fame(musicstore brand from Germany) dc power brick.
This unit is supposed to be a well regulated copy of the Voodoolab pp2 with regulated and isolated grounds. When I first bought this unit it worked sharms, but two weeks ago while connecting two guitar amps to a Paramix I've build, the 12v dc channel started humming. I thought it had something to do with the amps, but when I went back to my rig, the paramix, when running from that 12v channel continued humming. Any thoughts?
It is the only outlet that is working like that.

[drolo]

Hi, I have that power supply too. The 12V outlet is not regulated and hums.
The outputs of the transformer are all 12V. The normal ones are regulated to 9V but the 12V output isn't, as it would require at least 14 or 15 V to use a 12V regulator.

[garfo]

It isn't?? Well, that's new. But, I didn't get hum at first with the exact same pedal. 

[garfo]

It should be isolated since I believe you can take 14 volts from some of the outlets and since it is advertised as having all outputs isolated.

[drolo]

it is isolated but not regulated, at least from what I could see when opening the thing.

[garfo]

Still can't understand How it suddenly introduces hum. Anyway, I might have to look at a Voodoolab PP2 in the future.