Many say tube sound is nothing more than EQ and designer coloration, if this is the case would it be possible to exactly replicate tube sound through the use of a plugin?

Hi there, I believe this is my first post ever on headfi. I have a 2.1 setup which I'm content with, but I've been tempted to impart "tube" sound onto it. I fully realize that generally amps are transparent and any audible differences between them are done by the designer as seen by the workings...