What's the arm like thing on old turntables?

February 19, 2007 6:37 PM

I've noticed on some old turntables there's a kind of arm-like thing that can be put above the disk, and it's not the reading head, it's smaller and seems to have a spring... What is that for??
posted by PowerCat to Technology (26 answers total)

I no longer remember how they work, but it's an auto-loader, so you can put a stack of 5-10 LPs on the player and let them spin one after the other.
posted by autojack at 6:40 PM on February 19, 2007

Often/usually used with stacks of 45s, I believe?
posted by wemayfreeze at 6:43 PM on February 19, 2007

Best answer: I remember how they work. Not intended just or primarily for 45s. These were only found on "automatic" LP players

The central spindle would have a little "tooth" protruding out one side; you'd stack extra LPs on the spindle, and they'd sit on that tooth. The extra arm held the stack level, otherwise the LPs would flop all over the place. When the tonearm would automatically return at the end of one side, it would trigger some kind of cam that retracted that tooth just for a moment, allowing the LP at the bottom of the stack to drop; the tonearm would then return.

Generally speaking, double-albums were pressed so that one disk had sides 1&4, and the other disk sides 2&3. This was done so you could set up sides 1&2 to play consecutively, then flip the stack and play sides 3&4 consecutively. Triple albums were set up similarly.
posted by adamrice at 6:51 PM on February 19, 2007 [3 favorites]

33's as well. There was one of these at our cottage - I remember the phonograph could stack 5 albums one after the other.
posted by seawallrunner at 6:51 PM on February 19, 2007

Here is a video that shows the mechanism. They had them on LP, 33 1/3 record players too.
posted by lee at 6:56 PM on February 19, 2007

One of the problems I faced with these stacked albums (33's) was that if you loaded more than a couple, when the later ones played, the turntable would slow down because of the weight and the music sounded slowed. 45's not as much.
posted by JohnnyGunn at 7:28 PM on February 19, 2007

You have your answer. I just wanted to say thanks for making me feel so damn old. ;-(
posted by tellurian at 8:15 PM on February 19, 2007 [3 favorites]

tellurian took the words right out from under my fingers!
posted by illek at 8:49 PM on February 19, 2007

Yeah, me too. This question made a lot of us feel old.
posted by litlnemo at 9:44 PM on February 19, 2007

Next they'll be asking about the funny holes in the dial on those old phones.
posted by JackFlash at 10:13 PM on February 19, 2007

I too was going to post how old this made me feel. Instead let me offer this anecdote. I was recently having a drink with someone who pointed out that they were born after R.E.M.'s first album came out.
posted by Slarty Bartfast at 10:21 PM on February 19, 2007

To actually add some content to this, I'll add that it was common to have an insert piece you would put over the thin 33rpm-style spindle so that you could play the 45s automatically as well. In the US, 45s haven a larger hole than 33s do, and so the automatic mechanism in the spindle wouldn't work without some modification.

One way to deal with this was to get a plastic insert that would go in the middle of the record itself, semi-permanently. Here's a pic. But the other option was to use a thick spindle adapter that generally came with the turntable, and had the automatic mechanism built in. Some are pictured on this page (scroll down).
posted by litlnemo at 11:17 PM on February 19, 2007

Dreadful things. There'd be a loud crash as one record dropped onto the next, and the turntable would bounce around madly. Often the top record would begin slipping irregularly - especially if you were mad enough to try the full stack of five or six records. Maybe I just experienced particularly bad ones, but I think most people gave up on using them after a couple of experiments.
posted by Phanx at 12:56 AM on February 20, 2007

They worked fine for the 78's they were originally designed for, because those are heavier. They were also made of shellac or bakelite, which tended not to warp like vinyl. OTOH they were brittle. I have heard stories about 78's breaking when the autochanger dropped them, though I never saw this happen. I did break three of Dad's prized "Here's Hooey" records once after lifting the stack off the turntable and carelessly leaving them on the couch :-(

On our old Collaro turntable, the little tooth didn't retract, as such. The spindle had a little step for the bottom of the stack to rest on, and the little tooth reached up a little under one disk depth into the bottom of the stack and shoved the bottom disc sideways enough to drop it over the step.

The coolest thing about that turntable, though, was the way it figured out what size records it was playing. Before dropping the bottom record onto the platter, the tonearm would lift right up to the height of the stack, then swing in until it hit the edge, then swing out again; and after the record dropped, the tonearm would position itself over the leadin groove for whatever size records were stacked up.

What made this extra super cool was the simplicity of the underlying mechanism, which was essentially just a big grooved cam and a slipping clutch. It was so much neater than the forest of levers under the BSR turntables of the same era.
posted by flabdablet at 2:09 AM on February 20, 2007

Phanx, I used mine all the time. :) Some turntables I had were touchier than others, though. Usually if you used more than 3 records weird stuff would indeed happen. But it beat having to run back over to the record player every 3 minutes.
posted by litlnemo at 4:29 AM on February 20, 2007

My father had a very good turntable that did this, but it did an outstanding job. You could load a number of albums (I don't remember how many) and it would work absolutely flawlessly, playing the whole stack perfectly.

It was a very clever device, and a truly superb player. I remember my father bought special diamond needles for it; he claimed they were better and didn't munge the record as much. No idea what the brand was, anymore. We had huge Bose speakers and a good receiver, and had pretty darn good music for the 70s and 80s.

How things have changed. Right now, I'm listening to my Squeezebox... I can easily flip between an Internet radio station (NPR's on right now) and my entire album collection, instantly. I can hit play and not touch it again for weeks. What a difference a few paltry decades make. :)
posted by Malor at 5:19 AM on February 20, 2007

In the US, 45s haven a larger hole than 33s do, and so the automatic mechanism in the spindle wouldn't work without some modification.

More like, everywhere in the world, some 45s have large holes and some don't, with big holes being more common on jukebox records in Europe - the two sizes are because RCA wanted their records to be incompatible with Columbia's, which lead to big hole records, standard hole records, and standard hole records with snap-out large holes (more popular in the UK than elsewhere).

The temporary adaptors are called 'spiders' (in the UK at least), but dome shaped ones that fit over the spindle are better for DJing - you can just chuck the record over the dome.
posted by jack_mo at 5:49 AM on February 20, 2007

I like how one of the tags for this question is "old". Yes, yes we are....
posted by echo0720 at 6:59 AM on February 20, 2007

I would like to say that I am 25 and have used this feature throughout my life, and as recently as last summer. The turntable my family had growing up did it with no problems, except that the needle wouldn't usually drop on the right spot initially.
posted by lampoil at 7:17 AM on February 20, 2007

There is an old urban legend among radio DJs involving one of these. The details vary, but basically, back in the day, some DJ landed a hot date with a beautiful girl but she only had time to go out with him during his late shift at the station. He couldn't get anyone to fill in for him so he had the bright idea of using the autoloader to his advantage. He stacked it with records and went to meet the girl, expecting to come back in a few hours before the last record was over. As he was heading back to the station with his date in the car, he tuned in to hear how it was going, and to his horror discovered that the record was skipping somewhere on the first side of the first record. Probably BS, but it is a funny story I was reminded of by this thread.
posted by chillmost at 9:23 AM on February 20, 2007

Ask Metafilter 2037: "What's that funny thing with all of the letters I see people pounding their fingers on in old YouTube videos?"
posted by Caviar at 12:11 PM on February 20, 2007 [1 favorite]

jack_mo, I guess that is right -- it's just that when I was buying 45s, the US ones I bought were almost universally "big hole" type while the UK ones were standard or snap-out. So I didn't want to be too US-centric. :)

This thread makes me want to get another turntable. I don't have a working one now.
posted by litlnemo at 4:25 PM on February 20, 2007

Heh. "The reading head." I too feel old.
posted by kindall at 12:20 AM on February 21, 2007 [1 favorite]

We had an autoloader turntable that worked well, at least for a single album of four sides. Even cooler, though not as functional, is our turntable that plays both the top and the bottom surface of the record.
posted by Mitheral at 1:23 PM on February 21, 2007

It was Malor's "special diamond needles" that tipped me over the feeling-old edge.

Malor, were those styli spherical, elliptical, or parabolic?
posted by flabdablet at 7:24 PM on February 21, 2007

Perhaps they were moon rocks.
posted by kindall at 1:51 PM on February 23, 2007