Not only do I find myself using Racks to add wet/dry control to devices that don’t have it, I’m often using it to manually control the wet/dry balance with devices that have a built-in control to handle this. The problem is that, in many cases, the Dry/Wet knob doesn’t do what I want it to do.
For example, consider the Dry/Wet control on the Ping Pong Delay (or Reverb, Saturator, etc.).
As you turn it up, the delay signal gets louder and the dry signal gets quieter. Depending on what you’re doing, that can make getting the right balance trickier than it needs to be. By setting the delay to 100% Wet and putting it in a rack, you can easily control the volume of the delay separately.
The traditional solution to this problem would be to use the delay on a Return track instead – this method inherently gives you independent control over the effected and original signals. However, for productions where you use a lot of different effects on different tracks, this turns into way too many Returns to keep track of, making the solution above far more elegant.