Is this filter cap backwards??

[gadget73]

A lot of solid state gear uses a split rail supply, meaning there is a positive and negative voltage supply. At the main filter caps you'll see one with - to ground and the other with + to ground.

Some vacuum tube gear has a negative voltage bias supply too. Those have cap + to ground.

 

[elnaldo]

(We should clarify that all those capacitors with positive end connected to ground are NOT connected "backwards". They are connected with the higher voltage at the positive end and the lower voltage at the negative end)