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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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21st May 2020, 4:03 pm | #1 |
Dekatron
Join Date: Jan 2006
Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,814
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Mystery Question about vinyl record players
I've been listening to LBC [London Broadcasting company] fo a year or so now [mainly because I accidentally found it on DAB]. The James O'brien Show on Thursdays features a "Mystery Hour" [last one of three]. Originally designed as an adult "ask or answer anything you've always wondered about" section, the current stay at home situation has led to a takeover by 6-11year olds phoning in with some surprising and amusing results. A ten year old boy who uses Spotify himself, whatever that is wanted to know why vinyl record players have two speeds ie 33 1/2 and 45? A chap rang in and appeared right at the end [maybe a Forum member even] and it was all a bit rushed. This is quite a big subject really and I thought it might not get a response at all. There has been much discussion about the speeds inc 78 and others, sometimes linked to the Film Industry on here, in the past and it's another resort to book Milner's "Perfecting Sound Forever" book.
I looked for an open thread to hitch a ride but the quite long one opened by by Panrock 10/11/18 "Why bother 33 and 45 RPM" [he left out the half a rev] was closed. Did anyone else hear the Broadcast? What did you think of the explanation. I'm not seeking to be critical-it was very short, at hand over time and being on any media is stressful. All LBC programs are on line for a week or so if you want to check it out. An 11 year old girl rang in to ask the origin of Phobias. O'brien attempted an explanation, got tangled up and said "Perhaps we need to hear from someone more intelligent than me?" His young listener said "Yes, that WOULD be helpful". Moral-never perform with children or animals! I wouldn't have rung in myself for a variety of reasons. Also my ancient clam shell phone doesn't seem to do the short line txts to commercial numbers. I shall ask about that in the "modern" tech section. Dave W Last edited by dave walsh; 21st May 2020 at 4:11 pm. |
21st May 2020, 5:19 pm | #2 |
Heptode
Join Date: Oct 2007
Location: Southampton, Hampshire, UK.
Posts: 816
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Re: Mystery Question about vinyl record players
It's 33 and a THIRD, actually - your turntable must be running fast!
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21st May 2020, 5:26 pm | #3 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,550
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Re: Mystery Question about vinyl record players
I'm sure there have been discussions on record speeds and how they were derived. Try a serach.
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21st May 2020, 5:47 pm | #4 |
Dekatron
Join Date: Jul 2008
Location: Kington, Herefordshire, UK.
Posts: 3,658
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Re: Mystery Question about vinyl record players
Briefly :
78 was arrived at basically by trial and error, being the least worst compromise between playing time and acceptable quality/wear. 33 1/3 started with Vitaphone film soundtracks and was quickly adopted by the US broadcast industry for programme transcription. It possessed the covenient properties of being easily derived by reduction gear from simple induction motors at either 50 or 60 Hz. A 16" disc at this speed with a coarse groove could comfortably have a duration matching that of a standard 35mm film reel at 24 fps. 45 was brought in by RCA to compete with CBS' LP. The concept was that of a 78 using a microgroove and pressed in vinyl. The size and speed of the disc could be reduced and the system was originally marketed with a quick change mechanism which operated in a few seconds for a (nearly!) seamless side-change. The mechanism needed a 1 1/2" centre hole in the disc to accomodate the gubbins initially, and that carried over into juke boxes. For extended works, the RCA system was a non-starter compared to the LP, but the 45 soon found its niche as the three-minute carrier the popular music industry wanted. There are plenty more ins and outs, but that's the bones of it. |
21st May 2020, 8:04 pm | #5 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Mystery Question about vinyl record players
There's little to add. As above we have covered this in depth. One day the 10 year old may find us and be able to satisfy his curiosity.
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