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.

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

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

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

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?

Romy the Cat wrote:

... what do you feel would be the most suitable configuration?

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

Romy the Cat wrote:

I am personally inclined toward the BC scenarios.

Romy the Cat wrote:

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

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

Romy the Cat wrote:

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

Romy the Cat wrote:

The only concern I have is that both platters would have the identical speed…

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

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

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

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.

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.