Rogue Audio Cronus Magnum iii

I have a Rogue cronus magnum iii hooked up to a pair of Focal Aria 948 with morrow cables. When I turn the amp off there is a subtle static sound. It does not happen when switching on or while playing. This is my first all tube Amp. It reminds me of turning off my guitar amp years ago. Is this normal for tubes or do I have a connection issue? All the interconnects and speaker cables are secure. Do I need to check all the tube pin connections?

Thank you all