Post your Analogue Source pics here

Finally seems I manage to upload some pictures of my DIY TT with double motor and fly wheel, unipivot tonearm 12 inch.

Rgds

Adelmo
 

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Hi,

The plate that support the platter s bearing made as triangle it is floating by Magnetic Levitation. Inside each of the 3 the alluminum cylinder there are two mag repelling each other and keeping the platter floating. The mag repelling each other have the short coming to shift their center. The O Ring you pointed out ( one set for each of the 3 units ) keep the pivot of the mag centered.

Hope it is clear.

Rgds

Adelmo
 
I have not measured it but I think that there is close enough to zero resonances because the only contact between the platter and its bearing is the film of oil .Because it is a fully maglev bearing there is no point of contact to transmit noise.

The feet are interesting in that they are cups and spikes that are adjustable for height. The cup is the bottom element and it is that that I have sat on sorbothane pads 15mm thick.... it is the pads that do the damping..... I don't rely on the spikes for anything much.

I did use ( ebay ,Chinese ) maglev feet but , a ) I needed 6 of them to support the weight of the deck and , b ) I don't believe that they are in any way true maglev feet. They , I think , are magnetically assisted spring damped. They also only moved in one plane so were not really suitable to damp out the real world vibrations met by the deck in every day usage.

Hi,

Nice TT!!

Can you please tell me where you got the mag lev platter bearing. Also if possible the platter weight and magnets dimension.

Many tsk

Adelmo
 
Привет эдвард;
I like the way you think. I have just finished an SX 8000 copy. It is based on a meg-lev platter and a VPI motor. I am part way through making a Reed 3P tone arm. It can be seen on the left. See the YouTube

Cheers; Glenn

Hi,

Great work of yours!!!

Could you please tell me the platter weight and the 2 bearing magnets dimension?.

By the way, what kind of motor are you using? I understood is the same as VPI, can you tell me the type and brand?

Thank you in advance

Adelmo
 
Hi,

Great work of yours!!!

Could you please tell me the platter weight and the 2 bearing magnets dimension?.

By the way, what kind of motor are you using? I understood is the same as VPI, can you tell me the type and brand?

Thank you in advance

Adelmo

Hi Adelmo:

I have been working on a solution for suspending a plinth using maglev suspension for two years now to no avail. I never thought of o-rings. Brilliant! Mind if I borrow your idea? Nice work by the way.

The motor in mine is by Hurst and is used by VPI. It vibrates like a chain saw and requires a very heavy case. It's the PB series P/N 3203-001 They still sell them but they don't like to export. Got an American friend?...

I got the platter from ebay. No longer available I would guess the weight at 10 or so kilo. With a heavy platter the table weight can be less. The shaft is 9.97 mm. The rest is in the pic.
Where did you get your platter?

Cheers; Glenn
4953ab1d65178b98233c41526288fe9b.jpg
 
Hi Glenn,

Thank you for your information.

If the motor vibrate is not of my interest as I am looking for a silent motor. If a new motor do not vibrate I have interest in the future. At the present I am using a brushless motor taken from old floppy disk 5.5 inch. They have relative high torque and speed precision as well, outside rotor and 360 Rpm. They use 12 or 5 volts DC depending on the year of manufacturing. I took the idea from Origami, but I used the biggest available floppy motor, I suppose hard to find them now. As a feeding unit I use a normal PC feeder, I take out all the wires not needed and the cooling fan as well. Also for dimension reason and to have the feeding unit inside the motor case I trim the original case as well.

I do not mind you use the idea of the o rings for the mag lev, in fact some how is from AVID TT and should not be patent. However I use for DIY and myself only, not for sale or any profit.

The acrylic platter that is 47 mm thick x 320mm outer diameter was purchased from Germany 15 years ago when I made this TT from Scheu analogue but they do not sell it anymore. It was costly, not cheap. I think it is possible to get an acrylic platter from China, but I did not search well for it as my next project shall be based on a Lenco idle drive.

Best rgds

Adelmo
 
Hi Glenn,

Today I check my two motors RPM in an either unloaded and loaded by the 4.5 Kg fly wheel.

The RPM unloaded are 360.4 or 360 .5 RPM. Variation is just 0.1 Rpm.

In loaded state is the same, therefore happy to see that the torque should be enough .

Adelmo
 
To power these motors, I use a sine wave with the ability to adjust the frequency, phase and amplitude of the supply. At 33 revolutions, as a rule, the frequency is 50Hz, when the speed changes, the frequency, phase and amplitude change. When this is tuned, the motor spins smoothly and quietly.
 
Hi Alex,

Tks for the information but I do not know anything to electronic especially for these motors that have their own electronic controller.

Regarding the RPM at cold and warm bearing difference I have fitted in the bearing a heater and an adjustable temp controller with temp sensor.

Now in about one minute I got the 33.33 Rpm just heating the bearing around 29 to 30 Celsius. After that the bearing keep steady temp and also steady RPM.

I only play 33.33 LPs, but making a double pulley I could play also the 45 RPM record as.

I think a motor with fixed and steady 33.33 RPM is good as do not need to adjust but in reality follow the record speed need ( therefore late all the time correcting the speed ). But again I know nothing about electronic.

Now I get the wanted speed 33.33RPM almost immediately and the 2 motors and fly wheel keep pretty steady, 3 belt drives the platter I feel for the time being satisfied.

Now I need some cosmetic to fit the temp controller to the motor pod.

Tks n rgds

Adelmo
 
Thank you gentlemen for the information. Somewhere on this forum I recall reading about a signal generator that was sent though an amplifier to drive ac motors. I have a VPI motor controller that can be used if need be. I would to try something new with the stepper motors. I thought I saw one in your post.
Cheers; Glenn