As everybody knows, most of the square dance music is published using 45 rpm singles, so these are the most common music source for callers.
This makes turntables the most widely used music players in square dance. Turntables fall into three categories:
For a long time complete sound systems have been integrated into small, relatively easy to carry units. These units usually include the turntable, amplifier and one or two microphone inputs. Several companies made and make them especially for the square dance marked, among which Hilton Audio is probably widest known (I heared of some others, but do not have experience with them -HN).
Integrated turntables are rugged and, compared to other 'complete' systems, light and easy to set up. They are usually speed-adjustable in a very wide range. Some have a possibility to remotely reset the needle to the beginning of the record. On the other hand they have, compared to the other two turntable variants, inferior sound quality and usually a rather simple pickup system.
Integrated systems are preferred when light weight and small size are essential, records are used and their sound quality is sufficient.
Hifi turntables are occasionally seen in square dance use. Their main advantage is superior sound quality thru a more sophisticated drive and pickup system. With a lower needle weight (Auflagegewicht) they do not wear out records as much as other systems do.
Major drawbacks include: these systems are not made for transporting them every day, do not have a big speed adjustment range (if any). The low needle weight makes them prone to needle skipping
These systems should not be used for calling dances. But they serve best as a home setup for practising and dubbingrecords onto minidiscs.
Disco turntables like the 'classic' Technics MK 1210 (I have it and I like it!) combine the sound quality of an upperclass hifi turntable with the stability and speed adjustment possibilities of an integrated set. They would make perfect square dance turntables if they were not as expensive and heavy. They are constructed for heavy use, but permanent installation (or a big flight case).
There are lots of clones of the Technics available, which are aimed at semi-professional and amateur disco use and might be interesting as well.
If hifi or disco turntables are used for calling a dance, they must be combined with a mixer and an amplifier. Depending on the mixer a phono preamplifier might be necessary.