The replies you have gotten are pretty true. How can one describe a preamp sound? There are so many different "colored" preamps and different neve pres that it is impossible to say "this is the sound of neve." Also, there are many other factors that affect the sound along the way...musician's technique, instrument, room, microphone, mic placement, the list goes on. Your best bet is to get your hands on a pre and discover things for yourself. Having said that, I do feel bad for giving answers like this so I will try to give you a description, but remember this is not gospel and what one adjective means to me may not mean the same thing to someone else. It's the descriptions of sound that can be very misleading so take this with a grain of salt. Neve can be said to have a round bottom, creamy mids, and slightly compressed transients. Api can be said to have a tight bottom, forward mids, and perhaps faster transient response. What these descriptions really mean is subjective.