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02-02-2006 Post mapped to one branch of Knowledge Tree
Romy the Cat


Boston, MA
Posts 8,790
Joined on 05-27-2004

Post #: 1
Post ID: 2015
Reply to: 2015
A longer turntable belt.

Hey, people,

dose anyone know where can I find, buy, steal or order the large size of rubber belts for turntable. I’m looking for regular black thin and light belt, but I was not able to locate any sourse that would will to go larger then 38”. I need ~57-59”. I am sure there are some commercial fields (robotics perhaps, conveyers of something like this) where the long belts are available.

Rgs,
Romy the Cat

PS: Please do not propose me the alternate belts: fabric threads, fishing lines, reel-to-reel tape, dental floss, nylon belts and etc…


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
02-02-2006 Post does not mapped to Knowledge Tree
Antonio J.
Madrid, Spain
Posts 269
Joined on 08-15-2004

Post #: 2
Post ID: 2016
Reply to: 2015
Re: A longer turntable belt.
What about cutting it from the inner tube of a bike wheel? Race bikes usually sport tubeless tyres, but there are some big wheels using those inner tubes. I guess the circumference would be quite close to what you need.

Regards.
02-02-2006 Post does not mapped to Knowledge Tree
George
Posts 26
Joined on 03-23-2005

Post #: 3
Post ID: 2017
Reply to: 2015
And only $10
http://www.turntablebasics.com/beltmodels.html

http://www.elexatelier.com/

My dealer had some belts made for me many years ago without too much trouble. The problem, to me, was that the ends were spliced together and one could feel a tiny bump. The belts I am using today, from a VPI table, seem to be "continuous cast."

O-rings would be another approach.
02-02-2006 Post does not mapped to Knowledge Tree
TonyB
Toronto
Posts 16
Joined on 04-14-2005

Post #: 4
Post ID: 2018
Reply to: 2016
Make Your Own
You can use O-Ring splicing Nitrile cord used to make large O-Rings. Spaenaur has a splicing kit or separate splicing cord (kit 805-457, cord 825-173). The smallest cord has 0.070" diameter. One would have to see if the splicing bump is a problem.

There also may be some information in Teres archives. I sort of remember that there was a source mentioned at that time, maybe even fro ground belt. Chris Brady or Thom Macris may know.

TonyB
02-02-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 8,790
Joined on 05-27-2004

Post #: 5
Post ID: 2019
Reply to: 2015
"Belt" quandary: two platters
OK, thanks guys, it looks as I have found the belts. Here is another quandary for you to contemplate. If I would like have two platters of identical diameter by different masses (let call it full-mass on right and half-mass on left) to be driven by one single motor then what you fell would be the most suitable configurations? I have my thoughts about it but I would be interested to hear yours...




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
02-03-2006 Post does not mapped to Knowledge Tree
Antonio J.
Madrid, Spain
Posts 269
Joined on 08-15-2004

Post #: 6
Post ID: 2020
Reply to: 2019
Drive the higher mass with the motor
and use its inertia as "idle wheel" to drive the lower mass platter. Something like B but having the motor moving the higher mass platter.
Knowing you I'm sure that as soon as you have the belts you'll try every single arrangement for best results :-)


Regards.
02-03-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 8,790
Joined on 05-27-2004

Post #: 7
Post ID: 2021
Reply to: 2020
A double deck Turntable

Well, the "idle wheel" and “inertia ballast” ideas I do not think would be applicable to this case. I forgot to mention that both platters have high mass (42 and 62 kg) and therefore the normal worries that might apply to the belt topologies are not an issues in there. Also, I actually “drive” my platters by the belts (although they are very-very light-tensioned) instead to set the belts “to slip”.  I less concerned about the isolation and stability of the rotations - with this mass it is not an issue but rather with a desire to find out which platter would be in a “better belt-condition and which set as “referenced”. In my case the platter will have different sound, different purposes and use different type of arms/cartridges.

Rgs,
The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
02-03-2006 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 256
Joined on 08-03-2004

Post #: 8
Post ID: 2022
Reply to: 2021
Re: belt slippage
Hi Romy,

What kind of bearings are going to be supporting 42 and 62 Kg quietly?
I remember a Swedish friend making a 75Kg gunmetal platter some years ago. Sounded very nice as long as the bearing lasted (which wasn't long!)

Would there not be a benefit in turning the flywheel much faster and using gearing ie a small pulley above to 'drive' the platter supporting the record (a little like what the guy in Greece did)

If you deliberately allow slippage, the benefit of having a second heavy platter is surely lost as its kinetic energy cannot be usefully transmitted (when required) to the disc playing platter.  The high mass, thread driven decks like the Melco relied almost entirely on the platters mass not the motor power or the rotational energy in any external flywheel.

If it's speed stability you're after, give up these rubber belts, get an SP10 Mk2 in a decent plinth and worry about something else!
02-03-2006 Post does not mapped to Knowledge Tree
Wojtek
Pinckney (MI), United States
Posts 150
Joined on 09-01-2005

Post #: 9
Post ID: 2023
Reply to: 2022
Re: belt slippage

A magnetic tape (VCR) seems to be in fashion in some circles ,as a rubber belt replacement .Doesn't stretch like rubber and you can glue the required lenght as you wish .Custom motor pulley is required .
   Guy , I have SP10 sibling; SP-25 in original obsidian base .How much inferior this deck is in comparison to SP10 and should I build better plinth for it or I should not bother.
Regards, W

02-03-2006 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 472
Joined on 10-29-2005

Post #: 10
Post ID: 2024
Reply to: 2019
a complex physics problem
 Romy the Cat wrote:
If I would like have two platters of identical diameter of different masses (lets call it full-mass on right and half-mass on left) to be driven by a single motor, what do you feel would be the most suitable configuration?


A presents complex torque issues due to the platter mass assymmetry
D, F have very small platter-belt contact areas
B, C, D, F appear to have the same impedence matching issues, topologically.
E is the most complex to execute, so there are more things to go wrong but it avoids these other issues.

 Romy the Cat wrote:
... what do you feel would be the most suitable configuration?


Suitable is not a very clear term.  Each configuration achieves different objectives.
A allows a good comparison of platters.
C, E allow optimization of platter 1's sound more easily (more variables)
E allows optimization of platter 2's sound more easily (more variables)

A very complex situation.  What you choose depends on what your objective is.  Ultimately, the result may still be a surprise, and I would not exclude anything on the basis of theories.
02-03-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 8,790
Joined on 05-27-2004

Post #: 11
Post ID: 2025
Reply to: 2024
Identical speed…

Thanks, drdna,

I personally inclined toward the BC scenarios. I’m thinking to hard-couple the platters using a fairly high force belt between the platters. It would allow handling the micro-playing sin the bearings and make the momentum (kinetic energy) of the tandem very much higher. Then I thought to drive one of the platters (I did not decided which one) with one light, “hanging” belt.  The D and F scenarios are fine but I am concern that with different massed the platter would have different coupling and different micro-slipperage. Still, I presume that with this mass that all would be completely not relevant to sound, wouldn’t it be? The only concern I have that the booth platters would have the identical speed…

Rgs,
Romy the caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
02-03-2006 Post does not mapped to Knowledge Tree
gurevise
Posts 1
Joined on 01-23-2006

Post #: 12
Post ID: 2026
Reply to: 2025
Re: some thoughts
A: Looks very ineffective to me.
B and C look too similar.
D, E and F: I don't think they effective enough.

I think B or C would be the most effective solution.

I would agree that platter that heavy would require very "special" bearing to last a long time. I would think bearing that can handle high mass would be very noisy mechanically.  

What's the goal of this topology?


Sergey
02-03-2006 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 472
Joined on 10-29-2005

Post #: 13
Post ID: 2027
Reply to: 2025
Variable speed simply
 Romy the Cat wrote:
I am personally inclined toward the BC scenarios.

C allows for manipulation of the Platter 1 bearing with different belt tension in a linear fashion that includes a potential nadir in friction. 

B will hold the bearing fixed in two dimensions with variable force in two dimensions.

 Romy the Cat wrote:
Then I thought to drive one of the platters (I did not decide which one) with one light, “hanging” belt


Driving the higher mass platter yields a more equal distribution of transmitted vibration to each platter.

 Romy the Cat wrote:
The D and F scenarios are fine but I am concerned that with different masses the platters would have different coupling and different micro-slipperage


The flywheel in F allows for equalization of tensions.

 Romy the Cat wrote:
Still, I presume that with this mass that all would be completely irrelevant to the sound, wouldn’t it?


I would be careful making any assumptions.  Use experimental evidence.

 Romy the Cat wrote:
The only concern I have is that both platters would have the identical speed…


E allows for different spindle diameters on the flywheel, which will change Platter 2's speed independently.

Regards,
Adrian
02-04-2006 Post does not mapped to Knowledge Tree
tokyo john
Narashino, Japan
Posts 30
Joined on 01-30-2006

Post #: 14
Post ID: 2028
Reply to: 2019
Re: "Belt" quandary: two platters
Hi Romy, I have not read all the threads, but I remember seeing a picture in a Japanese audio magazine of 2 Micros driven in the C configuration. In my mind they both looked like RX5000s, but maybe they were of different weights/materials. Regards, John
02-04-2006 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 256
Joined on 08-03-2004

Post #: 15
Post ID: 2029
Reply to: 2023
Re: SP-25 & SP-10 Mk2

Hi Wojtek,

 

I've only seen/heard an SP25 once and I wasn't able to judge how good it was as the rest of the equipment was unfamiliar to me. There is some information about the various Technics DD turntables here.

http://de.geocities.com/bc1a69/technics_eng.html

As I understand it the SP25 was half the price of the SP10 so I imagine some compromises were made in it's design/manufacture.  For some reason the Obsidian plinths are very desirable and valuable so remember that if you ever sell it. The plinth may be worth more than the SP25! I don't actually think it works very well.

I also found that the sound of the SP10 was affected by using the supplied rubber mat. I took it off and use a mat made of 10mm polycarbonate sheet which sounds much better in my system.
I use the Stirling Broadcast plinth.  www.stirlingbroadcast.net

I like the SP-10 because it's perhaps the only turntable I've heard which allows you to forget that you are listening to a rotating vinyl record. It also does not seem to add or subtract anything.

I don't think I could or would return to a belt driven TT now.

best regards,

Guy

02-04-2006 Post does not mapped to Knowledge Tree
George
Posts 26
Joined on 03-23-2005

Post #: 16
Post ID: 2030
Reply to: 2029
Off Center

In the traditional setup of a single motor and platter the motor is "pulling" the platter towards itself, setup D. Could this be of any concern? Supposedly one of the reasons Clearaudio uses 3 motors (other than to charge another $10K) is to keep the platter "centered" over the spindle with equal force from three equidistant motors.

Setup F does give better platter centering but here there is less belt contact. This might be a good thing in terms of minimizing vibration transfer but might be more susceptible to slippage.

George

02-05-2006 Post does not mapped to Knowledge Tree
guy sergeant
United Kingdom
Posts 256
Joined on 08-03-2004

Post #: 17
Post ID: 2031
Reply to: 2030
Re: Off Center
The multiple motor approach is more applicable when the platter/subchassis/tonearm is suspended. It prevents the motor pulling the entire suspended mass towards itself when the stylus tries to slow the rotation of the record. It also allows alot of power to be applied to the platter without compromising the function of the suspension system.

In a non-suspended TT of the type that Romy is proposing that is less of an issue although if it is intended to use and transmit the power of a large motor to these platters, an arrangement such as F will prevent lateral wear/friction/noise in the bearings supporting them. However the motor and free running pulley will each be subjected to a uni-directional lateral force and may, in time become worn and noisy. It is still the configuration I'd choose of these options though.
02-05-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 8,790
Joined on 05-27-2004

Post #: 18
Post ID: 2032
Reply to: 2031
3 motors and “F” configuration.

George,

I do not think that the 3 motors example of Clearaudio is applicable. Theoretically it correct and a single motor driving a platter coastally minor-swing it on it’s bearing. In realty the things are more completed. With enough mass of platter the force that yank the platter when the belt “drives” become negligible and is not sufficient enough to allow any platter micro-playing. Furthermore the Micro- Seiki player are not sitting on a bearing (Model 8000 has no bearing as all under bottom) but a cushion of air low pressure air that very effectually dump the micro-playing, permanently (sine the platter reaches the cruse momentum) reacting to the driving force that applied to one side of the platter. Even further, some the Micro 8000 motors tune themselves to the tension of belts. In real live this feature do not work with larger Micro platters as they, given their kinetic force are quite stable in this gyroscopic inertia.

Also, the Clearaudio is wonderful demonstration how ebon the conceptually proper theories might not have any relation to Sound. If you listen this 3-motor turntable by Clearaudio then you realize that the misery of their sound is far further then the amount of motors they use. To talk about platters star-driving in context of Clearaudio is similar with assessing a LF of an amplifier in context of mini-motors that have -3dB at 80Hz ...

I myself like the “F” configuration a lot and I do not care about the slippage. The slippage might be modified by approximation of the motor and the idle roll to the platters and changeling the angles with wish the belt attach them. I even thought to valance with these angels (by managing slippage) the differences in the TT mass and the differences in the platters inertia. I juts do not think that I would have enough room atop of my stand to organs the “F” configuration in a way as it should be.

Rgs,
Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
02-05-2006 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 472
Joined on 10-29-2005

Post #: 19
Post ID: 2033
Reply to: 2032
Also consider these configurations
 Romy the Cat wrote:
I just do not think that I would have enough room atop my stand to organize the “F” configuration in the way it should be.


Romy,  To be complete consider these configurations:

G:  This is the smallest in terms of space requirements.  Slippage can be adjusted by moving the rotors further from the turntables (North-South on diagram) or moving the belts to the opposite side of the rotors.  Assymetry of coupling can be adjusted by moving the rotors closer to either turntable (East-West on diagram).  The belt contact area is relatively large.

H:  The simplest symmetrical configuration that allows for the two platters to turn at different speeds simultaneously.  Assymetry of coupling can be adjusted as above.  Belt contact area is relatively large.

turntables.bmp
Adrian
02-05-2006 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 8,790
Joined on 05-27-2004

Post #: 20
Post ID: 2035
Reply to: 2033
“D” configuration.
 drdna wrote:
G:  This is the smallest in terms of space requirements.  Slippage can be adjusted by moving the rotors further from the turntables (North-South on diagram) or moving the belts to the opposite side of the rotors.  Assymetry of coupling can be adjusted by moving the rotors closer to either turntable (East-West on diagram).  The belt contact area is relatively large.
Yes, Adrian, the “G” configuration looks very nice but what you I need another tension roll? I presume tat if I position the more clear and further for one of the platters than I would be able to offset the differences of mass. I will start those experiments is a week and it would be fun to see hoe it all works. Still, the “G” configuration is an improved version of “D” configuration. It is OK in respect the belt-platter contact but it is not partially comfortable from the perspective of tonearms real estate. The tonearm that located on the left of the left platter (on place of the motor in the “D” configuration) of is never useful as when you lover the needle of this tonearm you can not see the grooves. In your “G” configuration the motor take place of one or two back tonearms that are very comfortable to use.  One of the objectives for this project is that I have a functional need to put more tonearm/cartridges into a simultaneous use.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
Page 1 of 4 (61 items) Select Pages:  1 2 3 4 »
   Target    Threads for related reading   Most recent post in related threads   Forum  Replies   Views   Started 
  »  New  Ultimate Turntable..  Two things....  Analog Playback Forum     172  317247  05-31-2004
  »  New  My Analog Playback: the fat lady has sung..  My analog setup update....  Analog Playback Forum     9  47229  04-04-2006
  »  New  Maria Callas’s Glory Days: Available in Europe..  Here you are...  Musical Discussions  Forum     3  17867  08-26-2007
  »  New  Micro Seiki SZ-1T..  I guess it's my own fault....  Analog Playback Forum     2  17009  06-10-2008
  »  New  The Foolishness of Analog People..  Late to the discussion but cannot resist...  Analog Playback Forum     56  211342  01-30-2006
  »  New  A turntable platter as a turbine?..  A turntable platter as a turbine?...  Analog Playback Forum     0  5885  10-27-2010
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