IMO, there is no way to make the transition to wireless without sacrificing sound quality. That being said, if you must, or want to experiment, it all depends on your system. If you have a pre-amp that is feeding your amp with an extra set of outputs you can feed from there. If your amp have line level outputs (the blue RCA's on the Rachel) those could be used as well, as long as your wireless system is not looking for low frequency input.
Many possibilities...
Why don't you post your gear chain (list of system components) and lets poke around and find out.