DC Line Filter , Transformer buzz?

[GMaestro]

Hi I have a slight buzz on my valve amps' transformer which carries through to the speakers.

Will a DC line filter solve the problem? Or is there maybe a ground loop and how to solve that?

Any advice will be appreciated.

Regards
Gerrit.

 

[Steerpike]

 

[Family_Dog]

 

[GMaestro]

 

[Steerpike]

 

[Family_Dog]