Phantom Power Ticking Noise

[edwinstar]

Hello!
my 8 Channel SCA Preamp Chassis has developed a Ticking Noise that appears when i engage Phantom Power.
I will hear it on all Channels with Phantom ON (I have 4x N72, 2xA12, 2x J99).
With Dynamic Mics, there is no such Noise in the Audio, but with Condensers (U87 or KM184) that require Phantom Power, a Ticking in the Background is noticable.
Do you guys have an idea why this could be?
Thanks!