One thing that has not been mentioned here is the role the phono preamp plays in surface noise.
Many phono sections use loop negative feedback to execute the RIAA curve and control distortion. These preamps will be found to play surface noise to a much greater degree than a phono section that runs zero feedback.
This is due to a ringing phenomena that can occur in the electronics. It can cause the ticks and pops to be several times their actual duration on the LP surface.
If the phono section is zero feedback with passive EQ, the surface noise can be kept so low that one can easily be fooled into thinking there is no surface artifact at all!
There is also the phenomena of cartridge loading. With low output moving coils, the ringing artifacts of the undamped coils of the cartridge occur at ultrasonic frequencies. In addition, the cable capacitance can interact with the inductance of the cartridge to form a tuned radio-frequency circuit. The result is very much like RF being injected into the front end of the preamp!
This can result in a variety of behaviors, depending on the stability of the preamp. An unstable preamp will have excessive high frequency artifact; this can be tamed by the exactly correct cartridge loading resistor that damps the ultrasonic ringing. This is why cartridge loading is so critical with some preamps.
Now its a simple fact that feedback in electronics is a **destabilizing** feature of design. Conversely zero feedback designs are inherently stable. So if you have a zero feedback phono section, likely you will find that the loading of the cartridge is not critical, although it may affect overall noise.
It is the loading aspect when dealing with a phono section with feedback that can explain why one system is quiet while another of the same components is not.
If done correctly, the LP can seem to be every bit (no pun intended) as quiet as digital :)
Many phono sections use loop negative feedback to execute the RIAA curve and control distortion. These preamps will be found to play surface noise to a much greater degree than a phono section that runs zero feedback.
This is due to a ringing phenomena that can occur in the electronics. It can cause the ticks and pops to be several times their actual duration on the LP surface.
If the phono section is zero feedback with passive EQ, the surface noise can be kept so low that one can easily be fooled into thinking there is no surface artifact at all!
There is also the phenomena of cartridge loading. With low output moving coils, the ringing artifacts of the undamped coils of the cartridge occur at ultrasonic frequencies. In addition, the cable capacitance can interact with the inductance of the cartridge to form a tuned radio-frequency circuit. The result is very much like RF being injected into the front end of the preamp!
This can result in a variety of behaviors, depending on the stability of the preamp. An unstable preamp will have excessive high frequency artifact; this can be tamed by the exactly correct cartridge loading resistor that damps the ultrasonic ringing. This is why cartridge loading is so critical with some preamps.
Now its a simple fact that feedback in electronics is a **destabilizing** feature of design. Conversely zero feedback designs are inherently stable. So if you have a zero feedback phono section, likely you will find that the loading of the cartridge is not critical, although it may affect overall noise.
It is the loading aspect when dealing with a phono section with feedback that can explain why one system is quiet while another of the same components is not.
If done correctly, the LP can seem to be every bit (no pun intended) as quiet as digital :)