It is good for the buyer of a record player to understand the basic principles of vinyl playback: it gives them a better chance to make a successful purchase.
If you are a turntable designer, you need to know these things. If you are a music listener and are considering buying a record player, you will benefit from understanding the basics.
In the final reproduction of a vinyl record, the question is that the needle of the sound box should follow the microscopically small groove engraved on the record as closely as possible. The more precisely it can do this, the better the sound. To be able to perform its task, the sound box must be supported in its place completely stably, the disc must be firmly in place. Basically, in an ideal situation, the only moving part would be the diamond tip of the needle. Then it would produce a perfect electronic copy of what was engraved on the disc.
So in theory. In practice, the plate must rotate in order for the needle to travel in the groove, so it cannot be firmly in place. The sound box must be mounted on a freely moving sound arm so that it can follow the groove. So it can't be completely permanently installed either.
It therefore requires skill from the designer to get close to the above-mentioned ideal. At a quick glance, the turntables look very similar. However, this is not the case: a lot of design skills and, above all, production know-how are needed to achieve a good end result. The turntable should spin the disc at the correct, steady speed with no lateral (sideways) movement. The sound arm would have to be completely rigid, but at the same time light so that the needle of the sound box could follow the groove of the record precisely from start to finish. The final performance of the record player determines how close the design and implementation have come to the theoretical ideal.
Good design alone is not enough to get a high-quality instrument on a music lover's shelf. The designer's ideas have to be implemented and that requires a factory that can manufacture the parts to very tight tolerances and then assemble and adjust the turntable to exacting standards. Preferably on such a scale that the price of the instruments becomes reasonable.