He escrito acerca de las técnicas de grabación y principios 78 registros RPM etc. The early ‘80s saw the CD being introduced and we all watched Tomorrow’s World as they heralded in the new disc, saying it can even be played with jam spread on the surface! Ever tried it?? We were told the days of the LP and 45 rpm were numbered. Or where they?
The vinyl LP (Long Player) has been making a big come back. I have been supplying a steady stream of clients with restored record decks and pickup cartridges allowing mothballed collections of LPs and 45s to be played again.
The start of the Vinyl LP goes back to just before WW2. There was a bit of a battle between U.S. companies Columbia Records and RCA Victor. With improvements in recording techniques, there was a requirement to provide a recording media that was less “noisy”, could play for longer and was more durable than the brittle 78 rpm. Various formats were thrown up. These ranged from 10” to 16” diameter discs. A speed of 33,1/3rd rpm was commonly used as this was convenient for gearing down a synchronous motor running off mains electric. The larger discs were never really aimed at the public as the players would have been massive. They tended to be used in radio stations and contained pre-recorded music and adverts.
After WW2, the record companies got their act together and settled on a common standard. This was a Long Playing 12” disc (LP) running at 33 and a bit rpm. The width of the groove was reduced to .001” as opposed to .003” used in 78s. Esta, coupled with a slower disc rotation, meant you could get up to 30 minutos. of material per side. Pickups had moved on from the big heavy magnet-coil types and now the needle that sat in the groove was weighing a few grams rather than that of a sack of coal. The plastic vinyl material had a much smoother composition over the shellac used in 78s. This reduced the background noise. The only thing that the different manufacturers didn’t do until the ‘60s was to agree on the recording characteristics, which meant your HiFi enthusiast had to have a knob on is amplifier to “equalise” the playback sound of different LPs. ‘Spose it justified all the money spent!
RCA released the 45rpm 7” record in the late ‘40s. It was aimed at the popular music market, giving a play time of around 3 minutos. As your average American only had an attention span of no more than 3 minutos, it worked out just fine! This format came with a larger centre hole and was ideally suited for the automatic jukebox mechanisms. The increase in rpm (velocity) also meant that a louder recording could be made and replayed. This helped the sound reproduced on smaller budget players with only one or two valves in the amplifier.
10” 33rpm records were also made. These could contain 3-5 tunes per side and priced as a poor man’s LP. The format lasted longer in Britain than in the U.S, being used by Skiffle, Rock n Roll bands and comedy. “Best of Sellers” being an example.
During the ‘50s, the EP 7” 45rpm was released. This was an extended play record. The groves were closer together, so more material could be squeezed onto the disc, getting around 15 mins per side. The downside was, that the music recordings had to be ‘compressed’ more than normal, in order for it to sound ok. This resulted in a lower volume when played. Those with a budget Dansette, struggled to make a big racket.
By the late ‘50s, 78rpm records were being phased out. Although recordings of Hillbilly music for those in the U.S, down south, continued for a while, as they couldn’t afford a new fangled player!
It was normal for a record machine to have 4 speeds to cater for the different record types. Speeds were 78, 45, 33 and some 16 rpm. The latter slow speed was for records that were normally “talking books” and Language Learning. As the groove width for 78s and LPs (Microgroove) records was different, the pickup had 2 styluses. You would have to rotate a knob on the front of the pickup arm to select LP or 78. Playing a LP with a 78rpm stylus could be a bit messy, reducing the resale value of your LP!
Entonces, stereo came along…Next month. Apuesto a que no puedes esperar.