Idler Drive Turntables!
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- čas přidán 25. 08. 2024
- Inside the wonderful world of 70’s idler drive turntables and how they work!
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Them idler wheels they need to make more of for us folks who still rock the old 70s consoles! 👍🏻
Record-ology I use an emery board and sand off some of the motor shaft to slow the speed down. If you remove too much, take a little acrylic paint and paint the shaft to enlarge it.
I note that the unit was manufactured in England. Here in England we have 50 Hz AC mains. If you have 60 Hz AC mains, it would run fast. (That is, unless you have a unit that was designed for export and intended for 60 Hz.) In all probability, the design would be the same as for the UK market (except wired for your local voltage) and with smaller diameter drive shaft sizes to allow for the faster motor speed. Some motors had two 110 Volt windings that could be connected series or parallel to allow use at 220V or 110V, but as you say, the only way to change overall running speed is by changing driveshaft diameter.
The coil of wire on the 78 speed is normal. I've had a few ider drive turntables and they've all had that.
I have a Dual 1229 Turntable and I freaking love the thing! it's so simple and easy to use, easy to change speeds, and it has an auto return feature so i don't have to babysit my stereo! My Dual 1229 is awesome to use and I love the sound on it! its a vintage record player circa 1967, but I would buy it again and again and again! glad I have 2 of them in my collection. Very nice instructional video taking us under the hood of an idler wheel turntable. thank you!
Very cool!
It really is the crème-de-la-crème of idler-drive turntables! Peace.
I grew up with idler drive turntables (BSR & Zenith) The first time I saw a belt drive turntable, the nerd in me was amazed! 😂 And yes, all the idlers I had were made the same way with the coil of wire for 78 speed. They all had slight speed issues as well.
Having a changer like this one has its advantages. Older records were recorded at that "older pitch" as I call it. The same goes for tape machines. One interesting thing is I've even found variations between different BSR UA-25 models! Ones painted brown went faster, and ones painted grey went slower.I found that certain companies still used that faster speed to accommodate for people they were targeting that they knew had the older record players (like the budget labels made by SPC.) I've noticed it even on Blue Note reprints from the late 1980's made in France, like Bud Powell. One clue is you can time a song with a timer, if the song timing is listed on the record, and compare it. I'd LOVE to have one of those, especially a 4-speed. Happy record playing!
Thanks, Recordology, for providing us with a look under the hood of that idler drive turntable. It makes one appreciate the engineering genius behind such turntables back in the day. :)
Thank you very much!
Thanks for a very interesting video. I grew up in the late 70's and early 80's listening to records on idler drive turntables, BSR's and such like. I was always so fascinated with these turntables, how they worked and the awesome engineering genius of the mechanisms and how they were put together. Sometimes the idler wheel had some issues now and again but they were great turntables. Thanks for the memories.
Glad you enjoyed it
thank you very much for the helpful video, this helped me figure out how to repair my Invicta 1100 from 1972
Great to hear!
Love these changers...old school like me
Looks just like the mechanism in my 1973 Garrard changer. Mine plays a bit slow, but it is long overdue for maintenance. I enjoy your videos. From one "enthusiast" to another, keep up the great work!
Garrards are known for being slow, sometimes lowering the key of the music by a 1/2 step.
Thank you!
It looks very clean in there Recordology.always nice to see a well maintained and well cared for deck.idler wheel looks in good order.as long as its soft and not hard it should be spot on.
Thanks 👍
Another interesting and informative video from the fine folks at Record-ology. 🖐🙂👍
Glad you enjoyed it
Enjoyed seeing you 😉
Oh and a great show as always!this one is so much like a fidelity branded turntable I have here that is still in original box .
Thanks again!
The coiled wire for 78rpm is original.
The tape is likely original, or at least replaces the original. I've found it under the platters of my BSRs and my Magnavox. I think that old V-M changer on my shelf has it, too. It functions as a strain relief for those delicate signal leads.
The 33 rpm portion of the motor spindle (second 'step' from the top) looks like it's gathered some rubber material from the idler (that black band). That *WILL* cause a slight increase in speed. With the motor spinning, you can use a sharp knife (like an X-acto or one of those 'breakaway utility knives) to carefully carve that off. It won't fix the pitch completely, but it will help a little. THe more material that sticks to that motor shaft, the faster the record will play. It only takes a very thin layer to make the speed issue more noticeable. This is true of the inside surface of the subplatter, too, but your subplatter looks clean.
The coiled wire at the bottom of the shaft was indeed put there by the manufacturer. That's because the diameter of the bare motor shaft was insufficient to provide the correct speed for 78, so they had to 'build up' the shaft a little bit to correct it.
BSRs and Glenburns are naturally predisposed to running slightly fast. Yes, you can correct the speed by sanding down the motor shaft, but I do not recommend it because if you shave off too much it's not easy to add material. Put a couple of 'junk' records on the platter under the record you're playing, the additional weight sometimes helps correct speed.
Use a great deal of care if you're ever handling that motor directly. The topmost segment of the shaft (16 rpm) is very easy to break off or bend. Most people would not consider it a problem since the vast majority of the public have never even HEARD of a 16 rpm record, much less seen or owned one, but it's impossible to find a modern 16 rpm turntable today because the format has been defunct for almost 50 years. I bought both of my BSRs specifically because they had a 16 rpm speed.
Idler drive (aka 'rim drive' record players were the norm all the way into the 1970s, and for most folks they worked great Belt drive and direct drive have advantages over them, true enough, but idler drive was always simple, inexpensive, and relatively trouble-free. We went to belt drives because they became less expensive to manufacture and they did have an advantage that they didn't transmit motor vibration and rumble to the platter. Less vibration and consistent/accurate speed were supposed to be the advantages of direct drive, too.
Changing map to a 4 Pole motor might help
Reminds me of the way the Dual 1015 (original) was setup. When Dual did an update (1015(f)) they dropped the 16RPM, but added a pitch control that could be used to tweak the speeds.
Once warmed up (usualy about 5 minuteS) they were pretty well rock solid with speed. My 1015(f) has wow/flutter of 0.05% on all speeds.
Idler turntables are arguably the best out there when maintained. They are not as cheap to make as belt drive models though.
AC Voltage does not do anything as the motor speed is related to the cycles (60Hz or 50Hz).
I've heard people say how the diameter of the idler wheel doesn't make much of a difference, but I have to disagree with that. You're still changing the diameter of the wheel, it's just a slightly finer difference. I have a 50s Webster-Chicago record changer with an idler wheel drive that was going to fast. Obviously, I didn't want to shave down the motor spindle. So I increased the size of the idler wheel slightly with some tape(usually you glue a rubber band on the edge to prevent any noise, using tape and overlapping it will make a noise on every rotation. It's possible for it to be quiet; but it's pretty hard), cut off the access, and it corrected the speed.
Interesting to see an old device being so clean on the inside!
If it's an AC motor, the speed depends on the frequency of your power.
So if you have a 50Hz device and run it on 60Hz power, it will run too fast.
A can of compressed air to blow away dust should be used with caution:
If you accidentally blow dust into the bearings, it's a bit counterproductive.
Btw, a lighting tip:
Looks like I'm watching someone from Far Cry 5 with glaring eyes from the bliss chemicals.
The lighting you had previously, was definitely better IMO.
Recod-o-logy this is fantastic to show all about idler drive I too had a BSR playing too fast I checked the motor pulley at first I thought it was clean but I looked again it was slightly dirty so I used a bit of scotchbrite and used it to clean pulley there was some dirt on it ,I then checked the speed on 33 rpm which was running fast I used a strobescope on speed and lines were not moving and I checked at 45 rpm and the lines were still and not moving did the same thing on the Garrard TT I fixed it was running fast on 33&45 rpm but pulley was clean so I said what the heck I used very fine sand paper very fine tried it on the 34 & 45 both were fixed they both were running fast but after I did the sand paper trick it bought both speeds to be still when I check speed on both. the trick is to use Very FINE sand paper and touch it for a couple of seconds and just got to try and check speed for both 33&45. as I watched your vid I thought I saw some debris on your pulley but it could be lighting I know the scotch brite should work cause I use it a lot at my job for cleaning up and polishing my brass tools just trying to help JRo
Great info thank you!
Hi. Thank you for a great video. On the video when I watch it, It seems to me that there is some resedue on the 33 speed part of the motor shaft. Maybe a cleaning of it might help. All the best to you and have a great day.
Like most people, I enjoy seeing the guts of a product. You don’t see that everyday (though you could if you love to tear up your TT and put it back together again. I would say to that person GET A LIFE!!!).
I see several suggestions in the comments. What have you chosen to do about this problem? That would be interesting to see (video #4 coming up.....!!!).
I can always count on you to provide good content. Please keep it up!!!
Thank you!
My Dual turntable actually has a conical shaft. With a conical shaft you can make pitch adjustments by moving the wheel slightly up or down. Seems like the old Glenburn does not have this feature.
Oh that is interesting!
I'm working on an idler drive turntable that needs a new idler spring (that I can't find for the life of me)
It's a zenith F594W combo with an 8 track player
What about shaving off material on the inside of the platter? Maybe that wouldn't change the diameter significantly enough to make any difference.
Not sure though I think you are in the US and this can make a speed difference to your record deck especially the older models. The shaded pole type of motor used in many of the early decks was designed for 50 Hz electrical supply US is 60hz this does have a tendency to increase the speed.
Very good job!
Very detailed presentation.
You look like an expert!
Please inform. Where could I find those “orange in that case”rubber suspension pieces for the motor?
Great question! I am not sure where they came from unfortunately.
as the rubber wheel wears or shrinks, the speed will increase
That's not how it works. It's the speed of the motor and the ratio of the motor shaft size to the turntable rim that sets the ultimate turntable speed. Think of linear distance travelled by each part as it rotates.One inch of travel around the circumference of the motor (many turns) will be one inch around the circumference of the idler (less than one turn), and also one inch along the circumference of the rim (much less than one turn). This happens regardless of the exact size of the idler. Changing the diameter of the motor would change the linear speed in inches per second, affecting the turntable speed. Changing the diameter of the rim would change how linear inches per second along its circumference relates to the final RPM of the turntable, also affecting the final speed. But changing the diameter of the idler has no effect.
The diameter of the idler does affect the speed the idler itself turns at, just not the final speed. Another way of putting this may be that changing the diameter of the idler changes the ratio between the idler and the motor, but has an equal but opposite effect on the ratio between the idler and the turntable rim.
The above is true for single level idlers. Some idlers (RCA 45 players come to mind) have two different disks or levels, one that touches the motor and another that touches the turntable rim. If these age in a way that changes the ratio between the two disks' diameters, it will affect the speed.
No, the idler size is irrelevant. The size of the motor shaft is the factor. However, there is a grain of truth in what you say - the rubber idler, over time, eventually leaves deposits of rubber on the motor shaft, effectively increasing its diameter and causing the player to operate faster. I've opened up some record players from the 1950s and 1960s that were playing VERY fast to find the motor shaft covered with significant rubber deposits. Cleaned those off and replaced or restored the idler wheel, and the player's speed was pretty much dead on.
@@stevewahl5041 , size (diameter) is the speed. if you don;t believe me, shave some off the wheel and see what happens
If the subplatter rides on the rubber idler pulley, why wouldn’t increasing (or decreasing) the diameter change the speed? With a larger diameter idler, it seems to me that it would take the motor longer to make that idler make a complete revolution? I’m probably missing something
Does the gear on the turntable stem act as a direct drive to the table or does it facilitate the auto return function?
LIKE number 4 which is 3 plus 1 more. :)
the wire was put there when the motor was made
Those units are indeed sensitive to power at the outlet 50 Hz vs 60 Hz they will cause fast or slow conditions, in other words if the system was designed for 50 Hz and it is given 60 Hz it will run faster like wise if designed for 60 Hz and it is given 50 Hz it will run slower. This was built in to most reel to reel decks depending on location 50 or 60 Hz. A change of motor pulley would compensate for the Hertz variable. Some were changed electrically on the motor itself some had both pulleys built in and a groove change to the appropriate pulley would fix the variance. You maybe able to find the 60 Hz motor for it. Anyway good luck on that quest.
If he had a UK-equipped version wired for US mains, the speed difference would be radical - 20 percent fast, in fact.
exactly.....
i didn't know Glenburn made a 4 speed changer
Was it originally made somewhere with 50hz mains? That could cause the faster speed if you’ve got 60hz playing through a unit originally intended for 50
have you ever played any records by the "Platters",on those platters..i pretended to once,but it wasn`t great
I need to!
@@Recordology oh yes...i`m the great pretender..woaha woha...only platters record i know..lol
How about while the motor is rotating use a Dremel tool to lightly take off just a slight amount of metal of the shaft. Use a vacuum cleaner to pull away the dust while working on it.
If this were intended to be an 'audiophile' turntable, I'd say just use sandpaper or emery cloth and work very slowly, stopping periodically to reinstall the platter and test your progress, and be very, very careful indeed to not take too much off that spindle. Because if you take too much off, there's no easy way to recover. And finding a replacement motor for a four-speed unit is not as easy as you might think.
HOWEVER....,
This isn't audiophile gear by any stretch of the imagination, so let's put this in perspective. Minor discrepancies in speed are just part of their nature. If speed issues concern you THAT much, an LP120 or even an LP60 would be better choices, because those can be dialed-in without modifications.
I don't know but I would be concerned a Dremel tool may either work too quickly or make the sanding job uneven. A simple piece of ~ 500 grit sandpaper while the motor is running works well for me without adding wow/flutter. If you watch BSR repair videos you'll come across several variants on how to do this.
very good point
been long time and not up on somethings. But if the unit is for 50 hz that might be the problem I know in a jukebox you would use a pulley adapter from usa 60 to 50 . So that could be why it is a little fast. But let someone else that might know more chim in.
Another thing just to try check speed with a record or 2 on it and see if weight slowes it down. Other then that not sure. I just know I have fixed a lot of changers and they all have their own brains sometimes.
also to add looks like pulley 33 speed had rubber or junk build up. Try cleaning it with rubbing alcohol just dont get it on the rubber tire.
If the unit was built for 50 Hz, and played using 60 Hz mains, the speed difference would be ridiculous. Literally 20 percent faster. BSRs and Glenburns (along with several others) are noted for playing slightly fast, but it's like 1 or 2 percent, not twenty.
Techmoan discusses this in one of his videos. He imported a US Magnavox changer, and it played EXTREMELY slow. He had to hook it to inverter that suppled 60 Hz to get it to work right.
But given the fact that they are designed to play between 1 and 6 records automatically, it's likely that you're right about the additional weight of two or three records slowing it down a bit. I know the tone arm VTA is zeroed in to be 'dead on' with 3 or 4 records on the platter.
I wonder if the plastic turntable is subject to slight shrinkage over time. If so this could explain the speed problem?
Those changers were designed to play at a pitch of approx 2% fast. They felt that it added excitement to the music. Some radio stations today still play the music 2% fast.
Naw, the speed issue was noticeable (to a good trained ear) back when these units were new. BSRs were so commonplace and the slightly faster speed so prevalent, most folks didn't realize it.... and honestly, they probably would not have cared all that much if they DID realize it.
I noticed it because I had an open-reel deck that I used to tape songs off the radio. When I would later buy the records, it was fairly easy to compare the two and realize that the BSR was a wee bit fast. But it was still of very little concern.
That changer looks to have new motor mounts, and the o-ring [not "gasket"] is not original; nor is the modification to the 78 speed on the pulley [or "driveshaft" as you call it]. Idler drives were not just a thing of the 70's - they were made from the 1940's onwards. Apart from shaving down the pulley there's little you can do about the speed - they were set a bit fast because they were expected to slow down with a stack of records. Duals, some Garrards and other makes with idler drive had pitch controls. Idler turntable motors can be sensitive to power grid frequency which can vary. Garrard provided pulleys with slightly different diameters in North America to account for power variations across the grid. This is mostly undocumented. No such option with BSR/Glenburne changers I'm afraid.
cleaning the steps on the pulley should help teddy hashee also here on youtube has a video that shows him doing that
This sounds VERY interesting. From the 1940's, to 👎 now. From tube-type record players, to solid state. From my childhood, to 👎 now, ANY record player with an idler wheel (and, of course, a 120 volt, AC, direct-🚗 drive motor), is all the rage. There's something about the glow of tubes, the smell, and the sound of a rotten idler wheel tire (I guess I heard enough of this in my life, that I 👌 know what I 👍 like). It's annoying to a lot of people, but it's 👍 like a welcoming noise of 🏡 home. When ya 👂 hear this, ya 👌 know your turntable, or record player, is working (and, 👍 yes, needs service). This is a favorite amongst tube-type equipment (👎 not so much solid state,and I especially 👍 like console stereos that feature a record player). Be careful, especially if ya need to send and idler wheel off to be rebuilt. Just replacing the rubber tire alone, is around almost $35.00. Shipping is probably another $5.00. (roundtrip). I listen enough to 📻 Radiotvphononut's 📹 videos, that I 👌 know what I'm 👄 talking about. For profit reasons, this may, or may 👎 not work for ya. On all old equipment, 👎 nobody 👨 manufactures the idler wheels anymore. New old stock may be your best (or 👎 not) way to go. New old stock, I 👀 see as the next "aftermarket" for old vintage equipment. I 👌 know, sending those idler wheels off to be rebuilt, is expensive. Even if an idler wheel rebuilder is somewhere in your town (and I doubt that there is), chances are, it will be just far enough away to cost the same $35.00 to $40.00 in ⛽ gas, roundtrip. Sucks, I 👌 know. Same truth goes for CRT 📺 TV's (Cathode Ray Tube, or picture tube). Your friend, Jeff.