General Question about Belt Drive Turntables

[Mike Lavigne]

Just getting sources and speakers of the same floor helps a lot, mine are actually on 2 separate parts of the foundation and absolutely no connecting wood flooring.

using the Taiko Daiza's is essentially the same approach. various different impedance changes with some mass thrown in. 1.75 inches thick of solid Panzerholtz, then compressed closed cell foam layer, then a copper disc layer, then a Panzerholtz foam filled hollow footer.

every piece of gear has these underneath except my turntables, which have an additional Massif shelf with a ball bearing footer or 'plus' the Taiko Tana active system. and all the digital Wadax chassis also have the RevOpod decouplers, 32 of them.

all this on top of my solid wood Massif rack sitting on Nordost footers on 6 inches of concrete.

"takes a village"

 

[Balle Clorin]

Motor pod position has a significant effect on my belt drive Michell Gyro SE speed



Snapshot performance

 

[PeterA]

Are you using a stretchy rubber belt?

 

[Balle Clorin]

Yes this was with standard Michell belt, flexible yes. Seems kind of normal to me, tension is not high

Do not like the vibration I see, it can bee seen in the low level noise spectrum and as side bands

W&F

 

[Lagonda]

Yes this was with standard Michell belt, flexible yes. Seems kind of normal to me, tension is not high

Do not like the vibration I see, it can bee seen in the low level noise spectrum and as side bands

W&F

Looks like a badly machined pulley or bad motor bearing. I had that once on a Origin live pulley i enlarge the center hole on at home, had to order a new one and take it to a machine shop instead. I can recommend their belts too, made specifically after your own measurements in a special material. https://www.originlive.com/hi-fi/turntable-upgrades-modification/turntable-belt-upgrade/

 

[Balle Clorin]

Sadly my experience with OL is not as good as yours…. I think I better consult Michell.The motor is about 20years…

 

[Lagonda]

Sadly my experience with OL is not as good as yours…. I think I better consult Michell.The motor is about 20years…

I have gone trough maybe 5 OL belts, i really like the sound and have wondered why i have no static charge on my turntable lately, not noticing their claim of less static til i linked here today, the biggest hurdle was actually getting the size right, took a few tries. And one time i lost i nice chunk of hair adjusting the motor position, as my ponytail got snagged by the moving belt. A boxcutter close by ende up releasing me from my TT motor. I got lucky and did not mess up my arm, head or cartridge. You might need a pulley change for the Michell, they seem to use a round belt.

 

[Balle Clorin]

Your motor is too strong..

 

[Lagonda]

Your motor is too strong..

50 kg platter, tried a few different motors, from small to large, that motor sounds the best, with a wide leap in dynamics, tone and rhythmic drive ! You just have to keep your hair out of it.

 

[microstrip]

Motor pod position has a significant effect on my belt drive Michell Gyro SE speed

View attachment 143870

Snapshot performance

View attachment 143871

Unfortunately your data suggests a turntable with several problems, needing some care. The ClearAudio belt thickness is probably inadequate for the Girodeck pulley - it is the only reason I can understand why approaching the platter increases speed so much - the motor is synchronous. The side bands at 3050, 3100 , 3200 and 3250 show motor or belt problems.

Try using a variac lo lower the voltage supplied to the Michel transformer - as far as I remember it uses a 24Vac transformer, I had found in the past feeding the motor with a slightly different voltage reduced its noise. If problem of motor noise persists I suggest checking the dephasing capacitor.

 

[Balle Clorin]

Many thanks for your comments. This is a DC motor ..with original Michell belt.
I see a clear correlation between side bands and belt vibration . Playing a 3150hz and silent track with low noise floor and high resolution I can see the same frequency as in the side bands a noise peaks 100-200hz range. They are very much reduced and sometimes undetectable below the noise floor after belt service.
Then the visual belt vibration is also minimal.
Belt service = cleaning and applying talcum.

It would be interesting to make some “rollers wheels” support and dampen the belt in the gap between pulley and platter . Not sure how to implement that..

By the way belt/motor vibration noise is audible via a stethoscope held against chassis. But luckily nothing is audible at the speaker end, noise level is -60-80db below music/ reference level

 

[mtemur]

Dear @Balle Clorin,
In my opinion, there is nothing wrong with your turntable or its motor.

Lowering the motor voltage only works with AC motors. For AC motors, reducing the voltage lowers the torque while keeping the speed constant, as it is locked to the frequency. However, since your turntable’s motor is DC, lowering the voltage will decrease the speed.

The belt on your turntable is most likely sourced from Transrotor. If not, it is identical to the Transrotor mid-size belt. I recommend purchasing the Transrotor belt, as it is far superior to the Origin Live or LP Gear belts.

I have dealt with similar situations in the past, and in my experience, the following steps should help:

• Ensure the bearing is properly lubricated.

• Wash the belt with neutral hand soap and warm water. Clean the platter and pulley with IPA where the belt makes contact, and this time, do not apply talc to the belt.

• The pulley does not appear to be properly installed. You may have tightened the screw too much, causing an imbalance. However, this kind of imbalance can also occur after removing and reinstalling the pulley due to slack. I have even seen this issue on new turntables.

• Remove the pulley and clean both the shaft and the pulley. If there is slack between them, wrap a very thin layer of tape around the shaft to enlarge it slightly, ensuring the tape does not overlap. The goal is for the pulley to fit tightly onto the shaft by hand.

• If the pulley is correctly installed and perfectly centered, you should not see any difference in its position between when the motor is running and when it is stopped. Ideally, you shouldn’t be able to tell whether the motor is running just by looking at the pulley.
I hope this helps!

 

[mtemur]

By the way, the best approach is to use a stretchy belt to prevent motor vibrations from reaching the platter, especially a small-diameter belt and a high mass platter. This also allows for slight slippage, which helps reduce wow & flutter by minimizing motor control and speed irregularities from being transmitted to the platter.

Using a string provides even more slippage, which can help in this regard, but it is never as effective as a proper belt on dampening motor vibrations. This is why users of string drives often choose very thin, floss-like strings—to ensure sufficient slippage. Because slippage together with high mass platter helps to improve w&f and speed stability. In return start up and reaching 33.3 rpm speed takes long. However, string tension is incredibly important and very difficult to set properly.

Turntable designers who know what they’re doing incorporate ways to adjust tension correctly, like TechDAS, or use an additional pulley that presses the string with a spring, as seen in the Kondo Ginga. Alternatively, you can use a high-quality thin belt.

I know this because I’ve tested both methods. My turntable has a switch that allows me to use either a string or a belt. There are many things to consider about this simple looking situation.

 

[Lagonda]

By the way, the best approach is to use a stretchy belt to prevent motor vibrations from reaching the platter, especially a small-diameter belt and a high mass platter. This also allows for slight slippage, which helps reduce wow & flutter by minimizing motor control and speed irregularities from being transmitted to the platter.

Using a string provides even more slippage, which can help in this regard, but it is never as effective as a proper belt on dampening motor vibrations. This is why users of string drives often choose very thin, floss-like strings—to ensure sufficient slippage. Because slippage together with high mass platter helps to improve w&f and speed stability. In return start up and reaching 33.3 rpm speed takes long. However, string tension is incredibly important and very difficult to set properly.

Turntable designers who know what they’re doing incorporate ways to adjust tension correctly, like TechDAS, or use an additional pulley that presses the string with a spring, as seen in the Kondo Ginga. Alternatively, you can use a high-quality thin belt.

I know this because I’ve tested both methods. My turntable has a switch that allows me to use either a string or a belt. There are many things to consider about this simple looking situation.

What turntable are you using ?

 

[mtemur]

What turntable are you using ?

La Platine Verdier

 

[mtemur]

Here is an example of regulated string tension with spring loaded additional pulley. String is no knot, perfectly circular silk. Even the tonearm is proper, one of the best. IMHO it’s a much better match to this turntable than stock Kondo SME V-12.

 

[Lagonda]

La Platine Verdier

Great table !

 

[Balle Clorin]

• The pulley does not appear to be properly installed. You may have tightened the screw too much, causing an imbalance. However, this kind of imbalance can also occur after removing and reinstalling the pulley due to slack. I have even seen this issue on new turntables.

Thanks , did not realise the problem before making another slo-mo video today. By the eye alone I cannot see it. I’d never touched the pulley on this second hand TT. I have tried some other belts not from Michell, alternative belts were total fiasco dobling and tripling the wow. Never tried Transrotor. The belt I have now is NOS Michell originating from Japan. Far better than standard Michell belts.

 

[microstrip]

(...) • The pulley does not appear to be properly installed. You may have tightened the screw too much, causing an imbalance. However, this kind of imbalance can also occur after removing and reinstalling the pulley due to slack. I have even seen this issue on new turntables. (...)

This problem will probably show clearly in the wow and flutter spectra - measure the pulley active diameter and calculate the rotating frequency of the motor (per second) . Looking more carefully at it we see the side bands are not at 50Hz multiples, perhaps something like 45Hz. I was assuming a Michell with the old synchronous motor, the 50 Hz seemed obvious.

Eccentricity problems show easily in flutter spectra - I can associate any small peak in the A80 flutter spectra with a rotational part of it - it has many in the tape path.

 

[thekong]

Here is an example of regulated string tension with spring loaded additional pulley. String is no knot, perfectly circular silk. Even the tonearm is proper, one of the best. IMHO it’s a much better match to this turntable than stock Kondo SME V-12.
View attachment 144019

Thank you for the photo! I didn’t know the Gigna had that extra tension pulley, no wonder it came with the knotless string !