@rob67 The advantage of balanced operation is that you can avoid sonic attributes coming from the interconnect cable itself.
To achieve that, the output impedance of the source is very low. The other thing that is required is that the actual signal occurs between pins2 and 3 of the XLR, and ground is ignored.
When you do balanced any other way, such as with a passive volume control, you lose the primary aspect of going balanced, immunity to interconnect cables imposing a sound.
This is why it is possible for a good balanced preamp to be considerably more transparent and less colored than a passive control.