How much difference does a phono preamp really make?

The front end of the system is where you really have to get things right. It makes no difference how good your amps and speakers are, if the phono section isn't right (along with the turntable/cartridge itself) there's no way you can make up for that downstream.

The phono section is critical to the sound you get in a system. If it does anything suspect the best amps and speakers in the world won't make it right.

One thing poorly understood is how phono sections can generate ticks and pops that sound for all the world as if they are on the LP surface. These ticks and pops occur if the phono section has poor high frequency overload margins. A cartridge and tonearm cable have an electrical resonance that will be between 20-30dB more powerful than the actual signal. While this resonance might be at a couple of MHz, if energized by the cartridge output it can easily overload the input section of the phono preamp- and you get a tick when that happens.


A side benefit of a properly designed phono section (one that takes this phenomena into account) is that it will be less sensitive to 'cartridge loading'. Cartridge loading is the use of a loading resistor at the input of the phono stage. Its really there for the benefit of the phono section rather than the cartridge- it detunes that resonance I mentioned above. If the phono section is sensitive to that resonance, removing it will cause the phono section to sound better. But the act of loading the cartridge causes the cartridge to have to generate more current- and that in turn will cause its cantilever to be more stiff. IMO/IME you're better off working with a phono section that does not have this issue.

As a side note, I'm convinced that this engineering problem is a good part of why the CD came into existence, since back in the 1970s and 80s the majority of phono sections made had this tick and pop problem. If people didn't think that LPs had ticks and pops would they have been so eager to embrace the CD? ...