Hard to understand what you are saying without knowing the preamps you listened to. I have no idea what each designer was trying to accomplish unless I can see their designs. As a manufacturer, it is not as simple as designing a product that reproduces the original as I don't have any idea how the music was mixed and put together, etc. I can only interpret either what I like or what I think others may like. Plus I am limited to parts and can only try to select and combine them in a way to reproduce sound. To me, just having a circuit board in a component is an issue to begin with. I don't know who do design a product that is absolute neutral to your ears.
Happy Listening.