i recently bought a cheap vaccuum tube based microphone pre-amp (Samson C-Valve for $CDN 170) for recording live samples, but for fun i tried running a virtual analog synth through it, and WOW does it sound warm and fat when i overdrive it. there is some unpleasant hiss associated with the 50-60 db of gain i'm using, but most of it i can remove in cool edit. i imagine that this would be less of a worry with a better quality pre-amp.