To get the best sound out of 78s you should consider investing in the following:

—a receiver or amp with mono capability and a jack for plugging in a turntable,  two functions sadly lacking on most modern digital equipment. 

—analog equipment is preferable to digital, and vintage receivers and amps from the 1970s (the “Golden Age” of analog receivers) can be found for reasonable prices.

—a turntable capable of playing at 78 rpm.  Here, a modern piece of equipment is probably a better investment.  However, not all modern turntables have a 78 speed function, even those that are top of the line.  Ideally, the turntable would have a function to slightly slow or increase the speed.  Early recording engineers were not always diligent about recording exactly at 78 rpm, and for proper sound the speed of a 78 may need to be modified.

—a tonearm cartridge that uses different stylii sizes.  The grooves of a 78 are wider than those for an LP. Consequently, you will get a better sound playing  78s by using a stylus made especially for 78s.  And because 78 groove sizes and groove conditions can vary, it is advisable to have three or more 78 stylii of different shapes and sizes.

—a re-equalizer.  A re-equalizer is not an equalizer.  Prior to World War II the recording companies used varying equalization rates for their 78s.  Equalization rates were standardized in the 1940s for both records and playback equipment. When playing a pre-World War II 78 with modern equipment a re-equalizer will allow the record to play back with its original sound.

—a set of good speakers.