Originally Posted by PeteBr
At the risk of infuriating the drummer I've reduced a bit of tape hiss using the Low Pass Filter in the SSL mixer.
Although you wanted to achieve all of this in Reason, it's worth noting that other software is capable of using more sophisticated tools to reduce hiss. There's a noise reduction plug-in that comes with Sound Forge that can do a pretty good job of taking out noise without harming the desired sound (much). iZotope makes some kind of high-end software for audio cleaning/restoration. Now, granted this would mean buying other software, but I think it's important to know the options are there.