I'm sorry, you must be confused- plug ins don't work with waves of any color.
You see, waves are always in motion and there is simply no place to put a jack for a plug-in.
What you need is a analog to digital converter. The convertor takes the wave (which is analog) in one side and converters it to the 1's and 0's of digital. You will introduce some distortion in the process, but those 0's are the perfect place to put a jack for the plug-in. Most manufacturers have caught onto this trick and have made plug-ins even cheaper by using low-cost digital jacks. Cheaper converters will sometimes mount the jack on the 1's (it uses less screws) but the sound quality really suffers because the 1 is unstable and introduces some jitter to the sound.
So that's why plug-ins will only work in the digital domain. Hardware units use the same algorithms as the plug-ins, but they have the more expesive harware jacks so they cost more and (due to the distortion introduced by digital jacks) sound better.
Good luck!
Chris