So, finally all the parts for the play are on the table. It took almost 2 months for OLED display to arrive. But its all here now, including first choice of candidates for motor:
Again so much thanks to Richard for designing RPI pico solution, so elaborated and thought thru! It was a breeze to solder components on such nice PCB.
In the meantime I also finished 3 channel analog amplifier for UVW motor drive and had lot of very useful discussions about MC preamp on thread linked above...
But, big but, now when it is all ready for play, in 2 days me and family are going down south for holidays, 3-4 weeks nothing will happen here from my side.
This time I'm not sorry to leave project collecting dust for a while, first we will be swimming in nicest part of Adriatic, second is I will do my 2 weeks of the most favorite hobby (sorry it is not audio) ; fishing on open sea reefs. Going out few miles away from nearest (completely wild and unpopulated) coast and dropping fishing line some 50 to 100 m down under your boat (mine is just short of 5 meter, smaller the better for me) is such great experience, eating the catch the next day just complements.
See you soon, gone fishing 🙂
Again so much thanks to Richard for designing RPI pico solution, so elaborated and thought thru! It was a breeze to solder components on such nice PCB.
In the meantime I also finished 3 channel analog amplifier for UVW motor drive and had lot of very useful discussions about MC preamp on thread linked above...
But, big but, now when it is all ready for play, in 2 days me and family are going down south for holidays, 3-4 weeks nothing will happen here from my side.
This time I'm not sorry to leave project collecting dust for a while, first we will be swimming in nicest part of Adriatic, second is I will do my 2 weeks of the most favorite hobby (sorry it is not audio) ; fishing on open sea reefs. Going out few miles away from nearest (completely wild and unpopulated) coast and dropping fishing line some 50 to 100 m down under your boat (mine is just short of 5 meter, smaller the better for me) is such great experience, eating the catch the next day just complements.
See you soon, gone fishing 🙂
Thank you, very kind 🙂 I'm sure it will turn out very good , all ingredients and receipts are there, now just to cook it 👨🍳
Hello,
Finally I put motor drive together. complete solution from Richard @richb works as breeze, fantastic PCB, software just drag and drop, instructions in detail and sense; all works from first attempt. I never used someone else's project, this is too easy 🙂
Thank you Richard!
The only thing I changed is instead OP2134 I used NJM4580 opamps, I had those in drawer, cheaper and also fit for purpose. On scope I get perfect 3 phase sine waves 0.12% THD and -66db THD+N, all super fantastic for the purpose!
Finally I put motor drive together. complete solution from Richard @richb works as breeze, fantastic PCB, software just drag and drop, instructions in detail and sense; all works from first attempt. I never used someone else's project, this is too easy 🙂
Thank you Richard!
The only thing I changed is instead OP2134 I used NJM4580 opamps, I had those in drawer, cheaper and also fit for purpose. On scope I get perfect 3 phase sine waves 0.12% THD and -66db THD+N, all super fantastic for the purpose!
Potentially very good news for all seeking good TT motor. I managed to run 2 BLDC motors, from picture in post #41 just above:
1. up left: drum motor from Sony pro digital HD tape recorder
2. and bottom right: capstan motor from very cheap Philips VCR
Observation for both:
Little obstacle is that non of these motors is self starting. Or manual wind up or frequency ramp up is necessary to get to sync speed. Solution is in progress.
In coming days I'll test other motors that I have and then take few best potentials to machinist to make pulleys, so I can run TT.
Motor No 1 above is still very difficult to find, but No2 ishould be easy to reclaim from scrapped VCR!
Until further progress, best,
Dražen
1. up left: drum motor from Sony pro digital HD tape recorder
2. and bottom right: capstan motor from very cheap Philips VCR
Observation for both:
- running torque more than sufficient, pressed with fingers: hard to change speed or to stop.
- vibrations barely noticeable: when holding running motor in hands just very fine vibration is noticeable
- noise is only heard by bringing ear directly to the motor
- Both motors run on very low voltage, from 1.3 to 2.5 VRMS allowing PS of 3x power ump at only 5 to 8VDC. Currents are however significant, in level of 1Amp and more, but nothing to worry about.
Little obstacle is that non of these motors is self starting. Or manual wind up or frequency ramp up is necessary to get to sync speed. Solution is in progress.
In coming days I'll test other motors that I have and then take few best potentials to machinist to make pulleys, so I can run TT.
Motor No 1 above is still very difficult to find, but No2 ishould be easy to reclaim from scrapped VCR!
Until further progress, best,
Dražen
Hi Ralph,
No, they are all permanent magnet synchronous motors, by default they are not self starting.
Hysteresis and reluctance types are self starting, but they are so difficult to find as they are out of production for decades....
These what I'm testing together with @richb on remote will be very good I think, with some care and more electronics behind.
No, they are all permanent magnet synchronous motors, by default they are not self starting.
Hysteresis and reluctance types are self starting, but they are so difficult to find as they are out of production for decades....
These what I'm testing together with @richb on remote will be very good I think, with some care and more electronics behind.
Dears, so I run some tests with different motors now when I have something to spin it easily.
First to mention that Im running 3 power amps with help of beefy Sony surround receiver. I made mistake by making 3phase power amplifier before choosing motor. I had to consider currents and voltages needed before, and each motor is different, more hungry on current than on voltage. Anyway I smoked my TDA2030 approach and will come back to it later.
Second, all these motors are BLDC reclaimed from something and they all have their own drive electronics attached to them. I did not want to use any of that electronics but to feed windings directly with 3 phase pure sine wave as I showed above, thanks to Richard.
Point is that it takes nerves and precision to get directly to the windings, in 2 cases I did not manage at all so motors remain un-tested for the moment.
Third, the sources for the motors were:
a) cheapest possible Philips VCR, plastic casing and buttons , later called Phillips
No 1, Phillips VCR capstan motor
No2: drum motor from same VCR:
b) Ultra professional HD digital video with 4x 192/24 audio channels Sony HDW-2000, over 50000€ machine, later called Sony
No 3; Drum motor from Sony recorder:
And No. 4 capstan motor from the same Sony:
c) From some medical machine I took peristaltic pump motor: Papst VDC-3-54.14 This is newer version of EBM Papst motors.
No. 5: modern Papst outer runner:
Finally, what is common to all these motors and why I selected them is:
1. They are all 3 phase synchronous motors with permanent magnets
2. They are all outer runners (aussenlaufer) types. Number 4 could call "pancake" motor as rotor does not "skirt" stator windings, it is just above them.
First to mention that Im running 3 power amps with help of beefy Sony surround receiver. I made mistake by making 3phase power amplifier before choosing motor. I had to consider currents and voltages needed before, and each motor is different, more hungry on current than on voltage. Anyway I smoked my TDA2030 approach and will come back to it later.
Second, all these motors are BLDC reclaimed from something and they all have their own drive electronics attached to them. I did not want to use any of that electronics but to feed windings directly with 3 phase pure sine wave as I showed above, thanks to Richard.
Point is that it takes nerves and precision to get directly to the windings, in 2 cases I did not manage at all so motors remain un-tested for the moment.
Third, the sources for the motors were:
a) cheapest possible Philips VCR, plastic casing and buttons , later called Phillips
No 1, Phillips VCR capstan motor
No2: drum motor from same VCR:
b) Ultra professional HD digital video with 4x 192/24 audio channels Sony HDW-2000, over 50000€ machine, later called Sony
No 3; Drum motor from Sony recorder:
And No. 4 capstan motor from the same Sony:
c) From some medical machine I took peristaltic pump motor: Papst VDC-3-54.14 This is newer version of EBM Papst motors.
No. 5: modern Papst outer runner:
Finally, what is common to all these motors and why I selected them is:
1. They are all 3 phase synchronous motors with permanent magnets
2. They are all outer runners (aussenlaufer) types. Number 4 could call "pancake" motor as rotor does not "skirt" stator windings, it is just above them.
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For the test in this moment I focused on few easily to observe characteristics:
1. Hear-able noise
2. Vibrations felt in hand when holding spinning motor
3. Can it be stopped by medium press of finger at spinning rotor
4. Does it heat up more than I would like while spinning
Here is table (being work in progress) showing some numbers observed:
To go straight to the point, and people looking for TT motor will likely love, is that No1; capstan motor from super cheap Phillips VCR is the king here so far. It spins easy and with confidence. Very low voltages are needed. Vibration in the hand is barley noticeable and with drop of engine oil it is silent completely at about 50cm of distance (for my ears and background noise)! This motor has very long shaft of 3,6 mm and bushings for bearings.
Worth notice is also that it likes higher voltage with higher frequency which is easily adjustable with genius drive from RichB
With 24 poles, speed of this motor will be 250RPM @ 50Hz (120xfrequency/No of poles). For my case when driven pulley is TT platter of 300mm diameter, that would call for 40mm driver pulley which is OK (pulley would be proportionally smaller for TT's where sub platter is driven). However it runs very smooth also on 90 Hz (450RPM) so I can reduce pulley size and have lots of freedom to play.
Some comments on other motors:
No2 and No4 I did not manage to connect yet, construction and assembly makes it very difficult to reach windings
No3, Drum motor from Sony pro HD recorder. This is also very promising , 12 poles it makes it very suitable (500 RPM @ 50Hz). It also very non vibrant when held by fingers. There is some noise but that is from spinning naked video head that I did not remove yet. However it has 2 issues:
- It is not from cheap and available machine, one could spend years looking for scrapped Sony HDW-2000
- It runs on very low voltage and high-ish currents, standard audio amp will have some challenges here
No5. new Papst synchronous outer runner is disappointment in every way. While it is by far most powerful here, has carefully balanced rotor and incredible manufacturing, it is noisy due its ball bearings and vibrant quite a lot. This could be improved with effort of changing bearings to bushings, but still this is unit costing several hundreds of Euro, if one can actually buy it. For sake of common sense , I drop it, especially since No1 exists everywhere for anyone who wants to find it.
1. Hear-able noise
2. Vibrations felt in hand when holding spinning motor
3. Can it be stopped by medium press of finger at spinning rotor
4. Does it heat up more than I would like while spinning
Here is table (being work in progress) showing some numbers observed:
To go straight to the point, and people looking for TT motor will likely love, is that No1; capstan motor from super cheap Phillips VCR is the king here so far. It spins easy and with confidence. Very low voltages are needed. Vibration in the hand is barley noticeable and with drop of engine oil it is silent completely at about 50cm of distance (for my ears and background noise)! This motor has very long shaft of 3,6 mm and bushings for bearings.
Worth notice is also that it likes higher voltage with higher frequency which is easily adjustable with genius drive from RichB
With 24 poles, speed of this motor will be 250RPM @ 50Hz (120xfrequency/No of poles). For my case when driven pulley is TT platter of 300mm diameter, that would call for 40mm driver pulley which is OK (pulley would be proportionally smaller for TT's where sub platter is driven). However it runs very smooth also on 90 Hz (450RPM) so I can reduce pulley size and have lots of freedom to play.
Some comments on other motors:
No2 and No4 I did not manage to connect yet, construction and assembly makes it very difficult to reach windings
No3, Drum motor from Sony pro HD recorder. This is also very promising , 12 poles it makes it very suitable (500 RPM @ 50Hz). It also very non vibrant when held by fingers. There is some noise but that is from spinning naked video head that I did not remove yet. However it has 2 issues:
- It is not from cheap and available machine, one could spend years looking for scrapped Sony HDW-2000
- It runs on very low voltage and high-ish currents, standard audio amp will have some challenges here
No5. new Papst synchronous outer runner is disappointment in every way. While it is by far most powerful here, has carefully balanced rotor and incredible manufacturing, it is noisy due its ball bearings and vibrant quite a lot. This could be improved with effort of changing bearings to bushings, but still this is unit costing several hundreds of Euro, if one can actually buy it. For sake of common sense , I drop it, especially since No1 exists everywhere for anyone who wants to find it.
Apparently everything takes time, I had to clean my workbench and many other things not related to this,
Test LP is ordered, but will arrive just end of next week, in the meantime I will finish the set up.
This is as it was, before:
Middle phase:
Finally managed to organize space, I figured the time is to work with TT, so why not to listen a bit, my favorite mini monitors also found space on the desk. After:
Test LP is ordered, but will arrive just end of next week, in the meantime I will finish the set up.
This is as it was, before:
Middle phase:
Finally managed to organize space, I figured the time is to work with TT, so why not to listen a bit, my favorite mini monitors also found space on the desk. After:
I finally opened my TT as for tests I will use it without chassis. Here is fresh picture of inside, some copper unglued and I see that sometime I replaced tantal + film decoupling capacitors with X7R ceramics soldered directly on PS pins of SSM2017. This is inside:
Tonight I made few preparations, installed TT without housing for ease of access and temporarily fixed preferred motor (No1 above, cheap Phillips VCR capstan motor). For the moment I keep original pulley and use round belt ( my preference is thick flat belt, but for the moment I have no pulley for it). It all runs very good, no problem to start and keep speed. Keep in mind that this is very small motor and my stone platter is over 5kg.
Just for tests I attached motor directly on the plinth. When finished this will not be like that, motor will be mechanically coupled to base.
Even in this set up motor is quiet enough not to show any physically noticeable vibrations.
However rubber belt is not as steady as I would like, for the moment that's ok I think, nothing is optimized.
Just for tests I attached motor directly on the plinth. When finished this will not be like that, motor will be mechanically coupled to base.
Even in this set up motor is quiet enough not to show any physically noticeable vibrations.
However rubber belt is not as steady as I would like, for the moment that's ok I think, nothing is optimized.
Than I could not resist and connected my original vintage Papst asynchronous motor (this is rewinding motor from old reel to reel tape recorder)
It runs also with new frequency driver. Motor is specified for 165V 3-phase, I run it at max what I can get from my power amps : 40VRMS 3-phase, and it runs so smooth , it is kind of stealth... cant describe in words...
Still considering to keep it, regardless it is asynchronous. Rich's driver has option for tacho and very easy speed correction.... I will try that too and might be speed adjustment here and there could be good compromise for incredibly silent motor.
It runs also with new frequency driver. Motor is specified for 165V 3-phase, I run it at max what I can get from my power amps : 40VRMS 3-phase, and it runs so smooth , it is kind of stealth... cant describe in words...
Still considering to keep it, regardless it is asynchronous. Rich's driver has option for tacho and very easy speed correction.... I will try that too and might be speed adjustment here and there could be good compromise for incredibly silent motor.
One more small success thanks to Rich: tested tachometer with ease:
I used CNY70 reflective optocoupler from Vishay.
On the platter I just glued a piece of black insulation tape and brought sensor close to it, works from first attempt. White stone is reflective enough, and black tape is black enough.
On technicalities; photo transistor is loaded with 4k7 and 10k as Rich recommended, photodiode is loaded with 390 Ohm over 5V which gibes her approx 10mA to work (5V-1.2V =3.8V / 390Ohm =approx 10mA).
So what Rich made is that only one resistor needed to determine current for photo diode is needed, plus CNY70... 👍
I used CNY70 reflective optocoupler from Vishay.
On the platter I just glued a piece of black insulation tape and brought sensor close to it, works from first attempt. White stone is reflective enough, and black tape is black enough.
On technicalities; photo transistor is loaded with 4k7 and 10k as Rich recommended, photodiode is loaded with 390 Ohm over 5V which gibes her approx 10mA to work (5V-1.2V =3.8V / 390Ohm =approx 10mA).
So what Rich made is that only one resistor needed to determine current for photo diode is needed, plus CNY70... 👍
After some more runs I can confirm that motor No. 1 (pictures above) is definitely capable to run 5-6 kg platter in very heavy (lots of drag) bearing . I don't have accelerometer but with my fingers I cant feel any vibrations or hear noise. Speed of motor itself is very stable, speed of platter has oscillations from 33.32 to 33.35 RPM, this however is related to sub optimal o-ring belt that Im using at the moment...
Yet another mini success:
- Managed to attach RPM sensor at the side of the platter so I can run records, it works. See small wise grip fixed by masking tape, that is holding opto sensor
- refreshed oil both in TT and in motor (my favorite oil can is "Racing Kettenspray" next to instruments, since I stopped enduro biking this leftover is lifetime lubricant for TT needs
- tightened drive o-ring belt
Thing is even more stable now, and dead quiet.
On instruments you can see:
Finally, in the middle of the picture is speed display, it slowly toggles between 33.33 and 33.34... This should do
Next is testing with test record.....
- Managed to attach RPM sensor at the side of the platter so I can run records, it works. See small wise grip fixed by masking tape, that is holding opto sensor
- refreshed oil both in TT and in motor (my favorite oil can is "Racing Kettenspray" next to instruments, since I stopped enduro biking this leftover is lifetime lubricant for TT needs
- tightened drive o-ring belt
Thing is even more stable now, and dead quiet.
On instruments you can see:
- on the right: 2.15V AC, that is 2.15VAC x 3phase running this Phillips capstan VCR motor easily. Even with such small supply it is not easy to disturb this motor out of synch
- on the left instrument is measuring voltage drop over 3 ohm resistor. To save amp and motor, I installed 3 power resistors value of 3 ohm in series with each phase. It shows 1,529 VAC, divided by 3 ohm gives 0.5 amp drive current.
Finally, in the middle of the picture is speed display, it slowly toggles between 33.33 and 33.34... This should do
Next is testing with test record.....