Mrtennis, I would be hesitant in this case to take the face value of the phrase for its actual meaning; if you think of someone who has a laid back demeanor I think you get a better idea of what I am talking about.
As to your question, we avoid coloration by avoiding synergistic effects. None of our gear is built to synergize with another piece, be it one of ours or someone else's. IOW there is no voicing of any kind. We don't have to worry about the effects of a transformer, so it comes down to the quality of the coupling caps, how many stages of gain (one), that sort of thing.
Being able to compare against master tapes helps.
Getting rid of negative feedback turned out to be a fairly easy way to get 'laid back' sound (in this case, my meaning for the term, see previous posts) without sacrificing bandwidth. That **does** mean that certain speakers just will not work with our stuff; turns out there's a set of rules about how to predict that- see
http://www.atma-sphere.com/papers/paradigm_paper2.html