You've latched onto something of critical importance. So critical in fact that it applies not only to amp/pre-amp but to every component feeding a signal into any other component. From phono cartridge to phono stage to pre-amp, from CD to pre, from streamer, DAC, on and on. Critically important you study this to death until you understand it chapter and verse.
Until one day you wind up just like me, so expert you haven't the foggiest what any of yours are. Because: I lied. Its just not all that.
Until one day you wind up just like me, so expert you haven't the foggiest what any of yours are. Because: I lied. Its just not all that.