Shellac, as opposed to vinyl. You might think these all died out in the 1920s and were played on a wind-up gramophone with a horn speaker, but most of the rock and roll pioneers’ records came out on 78 format; Chuck Berry, Cliff Richard, Bill Haley, Elvis etc.
Unlike the vinyl revival, I’m not aware of any current releases, but you can still pick up 78s at record fairs and internet auction sites and they can sound surprisingly good.
If your family owned a record player in the 60s, here in the uk, there is a good chance it was a Dansette, which became a generic name, like hoover. These portable record players were build around an autochanger, usually BSR; Garrard being the other main manufacturer. An autochanger allowed 8-10 records to be loaded onto the spindle and played in sequence. So prevalent were they at the time, that many double albums, such as the Who’s Tommy had sides 1 and 4 on one record and 2 and 3 on the other. This allowed both discs to be loaded onto an autochanger and turned over together after the first two sides had played.
The amplifier was generally mono and typically had two valves – a rectifier and a triode-pentode. The ht came from the mains – no transformer – and the heaters were connected in series and fed from a tap in the record player motor.
These ‘Dansettes’ were capable of playing 33s (LPs), 45s (singles), 78s and 16s. 16s were relatively rare and were mainly used for talking books and MOR greatest hits for shops and restaurants, owing to their long playing time.
If you were very wealthy and had a hifi amplifier, you may well have had an option for playing 78s. In this case, the input would have been from a magnetic cartridge (moving magnet only in those days), in which case equalisation would be required. Owing to the nature of the crystal cartridge used by the Dansette and its ilk; output proportional to the amplitude of the stylus movement, the frequency response approximated to a flat response. With a magnetic cartridge, the output is proportional to the velocity of the stylus movement and equalisation must be applied to counter that with which the disc was cut.
Equalisation was applied to even out the displacement of the stylus across the frequency range and has the advantage in improving the signal to noise ratio of the final output, by reducing the level of the higher frequencies, as well as hiss and crackles.
Prior to 1945, the equalisation of 78s varied according to the year, the manufacturer and the country of origin, to say nothing of the whim of the recording engineer. Equalisation of 45s and LPs has remained largely unchanged, apart from a fad in the 80s to counter an assumed characteristic of the recording head. This correction is currently out of favour, although whether it made any discernible difference is up for debate.
Turntables for Playing 78s
The Pro-ject turntable can be modified to play 78s. The Audio-Technica’s popular AT-LP120-USB and AT-LP1240-USB can play 78s as standard. The classic Technics SL-1200 direct drive turntable can be modified to run at 78.
You will need a special cartridge; the groove size is larger than modern vinyl and the tip shape may need to be chosen according to the degree of wear, for optimum reproduction.
Equalisation will then need to be applied; either by electronic processing, or by a special 78 equalisation amplifier, such as the REK-O-KUT® ULTRA PREAMP from https://www.esotericsound.com/elect.htm.
In the instructions for Leak’s varislope preamplifier c1960, it notes that all complaints about the filters not working, turned out to be a result of deficiencies in customers’ equipment (either their speakers, or maybe their ears). Even if the speakers of the day (or at least the affordable ones) couldn’t reproduce the full audio spectrum, the same could not be said of the recording equipment. If your 78s have been looked after, they can sound surprisingly impressive away from the Dansette’s audio limitations.