Blackness has to do with intermodulation distortion. This is a property of all preamps and amplifiers. The lower the IM, the more the unit will be perceived as having a 'black background'. In principle it functions the same way in analog gear as Kijanki described in digital gear.
To lower IM, you have to increase linearity. The supplies have to be quiet, and incapable of modulation due to signal level.
Of course, the equipment should be low noise too :)
Note:
This statement is incorrect. LP mastering is one of the more unlimited audio processes in existence. The LP cutter has dynamic range far in excess of digital or tape and challenges the best microphones. It also has crazy bandwidth which is why CD-4 LPs were able to be made in the 1970s (CD-4 used a 50KHz subcarrier FM-stereo modulated into the grooves).
The limit of the LPs is in the playback. A cutter can make grooves no tone arm or cartridge could ever hope to track and it can do so without a hint of overload. But such grooves might throw a stylus and arm right across the record. All the processing comes in (dynamic limiting and the like) so you don't have to be all that careful to exceed playback limitations. Its just the record labels being lazy.
To lower IM, you have to increase linearity. The supplies have to be quiet, and incapable of modulation due to signal level.
Of course, the equipment should be low noise too :)
Note:
1. given the original limits of record cutting and playback equipment at the time, stuff was heavily EQ'd and dynamics were often constricted, essentially 'gain riding' to bring up the level of the soft passages to overcome inherent noise in vinyl playback.
This statement is incorrect. LP mastering is one of the more unlimited audio processes in existence. The LP cutter has dynamic range far in excess of digital or tape and challenges the best microphones. It also has crazy bandwidth which is why CD-4 LPs were able to be made in the 1970s (CD-4 used a 50KHz subcarrier FM-stereo modulated into the grooves).
The limit of the LPs is in the playback. A cutter can make grooves no tone arm or cartridge could ever hope to track and it can do so without a hint of overload. But such grooves might throw a stylus and arm right across the record. All the processing comes in (dynamic limiting and the like) so you don't have to be all that careful to exceed playback limitations. Its just the record labels being lazy.