A preamp can make a significant difference in sound. I suspect "the theory" doesn’t tell the whole story, plus there are different levels of "perfectly good".
The value of more expensive components means different things to different people. Not only do some people have deeper pockets and think nothing of spending $20K on a preamp, those who "get it right" also tend to have access to equipment that performs at a level many of us are simply unfamiliar with....similar to expensive cars. I would never spend $5K for performance shocks and racing tires for my Hyundai Elantra, but if I owned a McLaren it’d seem silly not to. Sometimes things just cost more, but sometimes they actually offer more too. A world class preamp is likely to have a better phono stage with more options, better line stage with more options, better switches, better connections, better build quality on everything, etc. In a highly resolving system, everything becomes more audible, but to make sense, all the components need to be at a similar clarity level. There’s distinctly diminishing returns as the prices go up though.
I have an excellent older (refreshed) Lazarus Cascade Basic tube preamp that was $650 new in the late 80s....it’d probably retail for closer to $2K now. It works well, sounds great to me, and is a good match for the rest of my system. As good as my preamp is, a Convergent SL-1 is better in every way, but it’s just beyond budget for guys like me, and I’d have to transform my entire system up to that level, or it’s advantage would be negated by the rest of my system.
The value of more expensive components means different things to different people. Not only do some people have deeper pockets and think nothing of spending $20K on a preamp, those who "get it right" also tend to have access to equipment that performs at a level many of us are simply unfamiliar with....similar to expensive cars. I would never spend $5K for performance shocks and racing tires for my Hyundai Elantra, but if I owned a McLaren it’d seem silly not to. Sometimes things just cost more, but sometimes they actually offer more too. A world class preamp is likely to have a better phono stage with more options, better line stage with more options, better switches, better connections, better build quality on everything, etc. In a highly resolving system, everything becomes more audible, but to make sense, all the components need to be at a similar clarity level. There’s distinctly diminishing returns as the prices go up though.
I have an excellent older (refreshed) Lazarus Cascade Basic tube preamp that was $650 new in the late 80s....it’d probably retail for closer to $2K now. It works well, sounds great to me, and is a good match for the rest of my system. As good as my preamp is, a Convergent SL-1 is better in every way, but it’s just beyond budget for guys like me, and I’d have to transform my entire system up to that level, or it’s advantage would be negated by the rest of my system.