You actually have done something wrong. Included you find an image of what it should look like. In the original post the value, send and receive objects are inside a patcher. Personally I don't think that this is the best way of making a stereo fader, or that the gain object is a useful object in terms of good gain control. Included an image with an expression based on a db scale, that has feel similar to the fader of a mixing desk. If you use that value to multiply two (or more) signals, one fader allows you then to control multiple levels at once.