All such products diminish absolute definition/clarity - no exceptions. They must, as they are not necessary devices inserted into the signal path. It is to be expected that the system will sound cleaner without any non-necessary device inserted.
This is not to say that such devices cannot confer a pleasing quality, and some people may like it better. But do not expect superior cleanness when inserting a non-necessary device into an existing rig.
This is not to say that such devices cannot confer a pleasing quality, and some people may like it better. But do not expect superior cleanness when inserting a non-necessary device into an existing rig.