The preamp is further up the signal path and therefore has a greater influence. So, while the right answer is always it depends because it is a system and components are different. But say maybe 65 / 35 pre / amp for thinking about it. But if you have an underpowered amp then upgrading this will have a disproportionate difference, as an example.
Q2.. All the components I have bought have not varied enough that it has influences Q1. In most cases the gain on the preamp normally been roughly the same as I swapped them. I remember some big differences in the 40 to 50 years ago timeframe.
Q2.. All the components I have bought have not varied enough that it has influences Q1. In most cases the gain on the preamp normally been roughly the same as I swapped them. I remember some big differences in the 40 to 50 years ago timeframe.