If I'm not wrong in calculating, 2um at 20 mm diameter pulley is 0.0001% or - 80db . that's acceptable
0.01% is 40db 🤔
6um over same 20mm diameter pulley should give 0.0003% or -70db, still perfect if it can be done in practice.
However, method I have chosen takes some time, than again I'm nt making series production but one off piece, so it is irrelevant cost - time wise.
6um over same 20mm diameter pulley should give 0.0003% or -70db, still perfect if it can be done in practice.
However, method I have chosen takes some time, than again I'm nt making series production but one off piece, so it is irrelevant cost - time wise.
Hi,
Last night I restarted my TT and have seen that paper strobe that I glued on the bottom of the platter slightly unglued on one spot, slightly touching optical sensor once every rotation.
I measured it like that by phone:
It is easy to see big change following exactly 1.3 second which is one turn for 45 rpm.
This phone app really gets things done , than I was wondering if there will be difference with stylus in groove and without it. If it is so sensitive it should capture stylus changes in friction too, This morning I removed paper strobe to free platter and this was set up:
As said, measured with stylus on record and without it, no changes to notice at all:
Last night I restarted my TT and have seen that paper strobe that I glued on the bottom of the platter slightly unglued on one spot, slightly touching optical sensor once every rotation.
I measured it like that by phone:
It is easy to see big change following exactly 1.3 second which is one turn for 45 rpm.
This phone app really gets things done , than I was wondering if there will be difference with stylus in groove and without it. If it is so sensitive it should capture stylus changes in friction too, This morning I removed paper strobe to free platter and this was set up:
As said, measured with stylus on record and without it, no changes to notice at all:
As conclusion, this App does all measurements that I need very sensitively. I can see even graph to analyze where any issue is coming from. A friend also used it on his TT, and results also there seem plausible.
Therefore I will stop playing with strobe and sensor, thing it is not worth it when this is easily available. Next will be test LP , with all variables included (LP, cart and arm).
Question; I'm thinking is it worth starting a thread to show benchmark of owners TT's by using this app? It is free to download and most people have better phone (with gyroscope), so it should be easy...
Therefore I will stop playing with strobe and sensor, thing it is not worth it when this is easily available. Next will be test LP , with all variables included (LP, cart and arm).
Question; I'm thinking is it worth starting a thread to show benchmark of owners TT's by using this app? It is free to download and most people have better phone (with gyroscope), so it should be easy...
Last 2 weeks I was rather busy with other things... Restarted TT after period it was resting, all works as it should, WOW by app 0.04% , slightly worst than when freshly oiled and 0.03%, but speed catches up 33.33 in few seconds, seems oil settled on right places.
Also visited recycling yard twice to trow my own garbage, both time picked an VCR from scrap , took motors out and returned the rest.
On picture is: left Aiwa and on right Panasonic VCR capstan motors, both from super economy plastic housing.
Left motor is almost identical to Phillips motor I installed and works beautifully, right one is very close to motors from professional betacam and digital video machines (again with ball bearings).
Anyway, properly recycling own stuff and by the way picking up old VCR , taking it apart and recycling again in pieces (eases job for people doing the job) is good strategy for me in finding TT motor..
Also visited recycling yard twice to trow my own garbage, both time picked an VCR from scrap , took motors out and returned the rest.
On picture is: left Aiwa and on right Panasonic VCR capstan motors, both from super economy plastic housing.
Left motor is almost identical to Phillips motor I installed and works beautifully, right one is very close to motors from professional betacam and digital video machines (again with ball bearings).
Anyway, properly recycling own stuff and by the way picking up old VCR , taking it apart and recycling again in pieces (eases job for people doing the job) is good strategy for me in finding TT motor..
Hi,
I used for my diy TT this kind of motor taken from an old 5 inch floppy disk. Torque is high, speed pretty steady. RPM around 300, need 12 V DC. Easy to implement in a TT.
Rgds
Adelmo
I used for my diy TT this kind of motor taken from an old 5 inch floppy disk. Torque is high, speed pretty steady. RPM around 300, need 12 V DC. Easy to implement in a TT.
Rgds
Adelmo
Hi Adelmo,
At beginning of motor seeking journey I considered HDD motors, stripped best candidate and drove it. While it is BLDC and it turns really smoothly, it is too small and to weak unless platter is really light and bearing loose.. Could be an idea to put 3 of them in arrangement around central shaft with common belt, or 3 separate belts, but I did not go in that direction. Nevertheless, as one unit turning several kg platter with drag in bearing, it is to weak.
You said that you made diy TT, speed is around and pretty steady, well that's not too articulate. If you wish show us what is done, This is great forum to be opened about own innovations, mistakes, learning and sharing. (Ok, I admit this was lame from me , but still it is ok).
Cheers,
Drazen
Hi Drazen,
Mine is not an innovation at all, it is dated at least 18 years when I made the TT and regarding the idea was taken by an English web : Origami that used brush less Floppy disk motor. The main difference I did was to use a bigger floppy motor, the one used for 5.5 inch floppy that is also brushless, but more powerful than smaller floppy motors. It has 2 bearings, but could be modified into bushes.
Sorry but I am not technical at all for electrical things, therefore in my execution I have used a motor as the one I showed in the picture, bonded the 3 belts pulley to it, incapsulated everything in a heavy steel case, used a standard 550 Watt PC feeder that delivery 12 V dc as PSU to the motor s PCB. My platter including the Puc it is over 5 Kg.
I do not have fine speed adjustment as I use only vinyl with 33.33 Rpm, therefore I have tuned the pulley diameter to achieve it. The electronic card of the motor keep the speed steady, the PC feeder delivery the 12 V Dc. Not the best but good enough indeed.
Best regards
Adelmo
Mine is not an innovation at all, it is dated at least 18 years when I made the TT and regarding the idea was taken by an English web : Origami that used brush less Floppy disk motor. The main difference I did was to use a bigger floppy motor, the one used for 5.5 inch floppy that is also brushless, but more powerful than smaller floppy motors. It has 2 bearings, but could be modified into bushes.
Sorry but I am not technical at all for electrical things, therefore in my execution I have used a motor as the one I showed in the picture, bonded the 3 belts pulley to it, incapsulated everything in a heavy steel case, used a standard 550 Watt PC feeder that delivery 12 V dc as PSU to the motor s PCB. My platter including the Puc it is over 5 Kg.
I do not have fine speed adjustment as I use only vinyl with 33.33 Rpm, therefore I have tuned the pulley diameter to achieve it. The electronic card of the motor keep the speed steady, the PC feeder delivery the 12 V Dc. Not the best but good enough indeed.
Best regards
Adelmo
Well, @Adelmo , this looks very very nice! I like view of suspension you made, even I at the moment don't see how it works. You also made own tonearm as it looks. Also like triple oring belt that will eliminate single oring issues...
If you have time and will, if I'm you I would make a thread about this project, it looks great! Seems you are more in mechanics than electrics, same here with me.
Motor drive is not very demanding thing any more thanks to @richb and his Supaspin, There are other solutions available here on forum, my opinion is that this is most elegant one. you don't need to be in depth to make it work, just assemble it and t works.
If you have time and will, if I'm you I would make a thread about this project, it looks great! Seems you are more in mechanics than electrics, same here with me.
Motor drive is not very demanding thing any more thanks to @richb and his Supaspin, There are other solutions available here on forum, my opinion is that this is most elegant one. you don't need to be in depth to make it work, just assemble it and t works.
HI Drazen,
You can find on 118 message of the : Post your analogue pictures here ...... thread what I posted time ago. Actually my floating TT decouple very very well, I can knock as hard as I can the plinth while playing music but nothing happens and music keep as normal. However if you plan to use a TA like the F.S. LT, in my opinion floating TT is not so good. Lately I no longer use the wood TA in the picture, I use a kind of clone of the LT tonearm, therefore to test it I used a bit modded Lenco not floating.
My floating unit it is made with mags, therefore since the the 2 repelling mags of set the shafts the rings keeps the mag s shaft centered.
Regarding the motor unit I also made an attempt using the fly wheel and 2 motors, but mechanically speaking was not lathed well as supposed to be and introduced vibration and W and F to the system, therefore I went back to the single motore and 3 belts. I still think if made well, was a good system that worth to use for belt drives.
Best regards
Adelmo
You can find on 118 message of the : Post your analogue pictures here ...... thread what I posted time ago. Actually my floating TT decouple very very well, I can knock as hard as I can the plinth while playing music but nothing happens and music keep as normal. However if you plan to use a TA like the F.S. LT, in my opinion floating TT is not so good. Lately I no longer use the wood TA in the picture, I use a kind of clone of the LT tonearm, therefore to test it I used a bit modded Lenco not floating.
My floating unit it is made with mags, therefore since the the 2 repelling mags of set the shafts the rings keeps the mag s shaft centered.
Regarding the motor unit I also made an attempt using the fly wheel and 2 motors, but mechanically speaking was not lathed well as supposed to be and introduced vibration and W and F to the system, therefore I went back to the single motore and 3 belts. I still think if made well, was a good system that worth to use for belt drives.
Best regards
Adelmo
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Hi Adelmo,
I have seen pictures, very nice again!
Also checked 5" floppy motors, they came in same varieties as VCR capstan motors that I use,all BLDC, in one case 24 to 36 slots and 16 magnets, and in other case slot-less 6 coils and 8 magnets. Same as my picture in #270 above. For some reason for now all slotless motors came with ball racers.
Do you have pictures of your motor inside, I would like to see.
Also did you measure W&F, results could be interesting if you did.
I see your sunspension now, very cool overkill 🙂. If (or when) I do new TT from scratch, this will be considered.
I have seen pictures, very nice again!
Also checked 5" floppy motors, they came in same varieties as VCR capstan motors that I use,all BLDC, in one case 24 to 36 slots and 16 magnets, and in other case slot-less 6 coils and 8 magnets. Same as my picture in #270 above. For some reason for now all slotless motors came with ball racers.
Do you have pictures of your motor inside, I would like to see.
Also did you measure W&F, results could be interesting if you did.
I see your sunspension now, very cool overkill 🙂. If (or when) I do new TT from scratch, this will be considered.
Hi Drazen,
sorry I do not have picture of the inside of the motor being a too old project. However these old Japanese motors were build with good quality including the bearings. Bearings, if needed, are not complex to be replaced by better ceramic bearings or bushes. At that time I had for free these motors as I took them out from wasted PC floppy disk, now seems hard to get them and costly when available, at least here. Pity as I liked them much.
I did not check the W&F, I checked the speed with a laser beam digital tachometer only and was pretty steady. I do not trust much these smart phone app.
Best regards
Adelmo
sorry I do not have picture of the inside of the motor being a too old project. However these old Japanese motors were build with good quality including the bearings. Bearings, if needed, are not complex to be replaced by better ceramic bearings or bushes. At that time I had for free these motors as I took them out from wasted PC floppy disk, now seems hard to get them and costly when available, at least here. Pity as I liked them much.
I did not check the W&F, I checked the speed with a laser beam digital tachometer only and was pretty steady. I do not trust much these smart phone app.
Best regards
Adelmo
Small contemplation on pulley and belt;
I have chosen thick flat belt and crown pulley for good reason, O-ring belt in V groove will make WOW directly by any imperfection in O-ring diameter, flat belt is to great degree immune on that.. Here is picture that explains.
However, using multiple O-rings, like Adelmo used 3, or a friend has 2 on his VPI Scoutmaster, greatly overcomes this issue by distributing diameter imperfections over few belts.
With polished crown pulley and flat belt (see post #256), I discovered that there is significant belt slip over driver pulley. It is solved by tighter belt. See my post #233.
V groove pulley with O-ring will have much less slip just because of geometry, but IMO multiple O-rings must be used to reduce WOW created by diameter tolerances.
Here is video showing proof that belt slips on driver pulley. I applied roughly same pressure on motor (no changes in speed) and on platter (visible change in speed). Only conclusion is that motor is in sync and rotates stable regardless of load, but belt slips.
It would be interesting to learn how to increase friction to crown pulley while keeping its precision (I'm thinking of etching in acid). Double or triple o-ring is alternative...
I have chosen thick flat belt and crown pulley for good reason, O-ring belt in V groove will make WOW directly by any imperfection in O-ring diameter, flat belt is to great degree immune on that.. Here is picture that explains.
However, using multiple O-rings, like Adelmo used 3, or a friend has 2 on his VPI Scoutmaster, greatly overcomes this issue by distributing diameter imperfections over few belts.
With polished crown pulley and flat belt (see post #256), I discovered that there is significant belt slip over driver pulley. It is solved by tighter belt. See my post #233.
V groove pulley with O-ring will have much less slip just because of geometry, but IMO multiple O-rings must be used to reduce WOW created by diameter tolerances.
Here is video showing proof that belt slips on driver pulley. I applied roughly same pressure on motor (no changes in speed) and on platter (visible change in speed). Only conclusion is that motor is in sync and rotates stable regardless of load, but belt slips.
It would be interesting to learn how to increase friction to crown pulley while keeping its precision (I'm thinking of etching in acid). Double or triple o-ring is alternative...
At beginning neither I did, but doing several crosschecks, it seems it works. Actual speed is not precise, but wow is very accurate. See my earlier posts here...
Your finger pressure on a small diameter motor is much less compared to the platter because of the size difference of the two discs. Leverage on the platter will be much more than on the motor pulley. But yes, I agree that it is highly likely that the belt is slipping on the motor pulley. Reminds of what happens to vacuum cleaner belts. They will slip on the shiny motor shaft rather than on the larger rotating brush shaft.
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