We all know the flat T/T belts are nearly used universally for belt driven T/T's. Most know of their big disadvantage, they stretch which induces speed incontinences. The answer for many is to use Mylar tape belts which do not but these are a little fiddly to make up.
So what if we combined the two. have a rubber flat belt on the inside with a Mylar belt stuck (adhered) around the out side of the rubber belt. Surely that would give us the best of both worlds.
Cheers
So what if we combined the two. have a rubber flat belt on the inside with a Mylar belt stuck (adhered) around the out side of the rubber belt. Surely that would give us the best of both worlds.
Cheers
Hi, yes I know about rtr tape, but that suffer's from the same problem as standard Mylar. Again Pain to make up & does not grip as well as rubber.
Cheers
Cheers
Something non stretchable glued to the outside of a rubber belt? Stop and think what happens as that rubber belt goes around the motor pulley. Still think this idea will work?
BillWojo
BillWojo
You are being OCD, measure it first.
The Japanese would have done something long back.
Thorens has the same size for all their models.
Idler type drives exist, no idea if belt needed.
And it is a common enough part, to be replaced periodically, why are you worried?
The belt needs to flex, and not stretch?
Only thing I can think of is a metal chain.
Try and get one, preferably in silver alloy, very conductive.
The Japanese would have done something long back.
Thorens has the same size for all their models.
Idler type drives exist, no idea if belt needed.
And it is a common enough part, to be replaced periodically, why are you worried?
The belt needs to flex, and not stretch?
Only thing I can think of is a metal chain.
Try and get one, preferably in silver alloy, very conductive.
Too many obsess over trivial things for no reason.
Must be something in the water.
The following is a additional information supplied to a very good report made about a replacement TT belt that is being trialled.
I would not know if it is on topic or off topic.
here's the measurements. ( same place from start of track, same up to speed time, same volume, same windowing, everything)
Lower signal level away from the fundamental, significantly lower at the motor rpm and 2x of motor rpm. narrower, straighter fundamental and much smoother at base of fundamental. That's clear indication of better speed stability and a reduction in transmission of noise from the motor (250rpm)
I would not know if it is on topic or off topic.
here's the measurements. ( same place from start of track, same up to speed time, same volume, same windowing, everything)
Lower signal level away from the fundamental, significantly lower at the motor rpm and 2x of motor rpm. narrower, straighter fundamental and much smoother at base of fundamental. That's clear indication of better speed stability and a reduction in transmission of noise from the motor (250rpm)
It's not quite that simple. Think of the belt/platter/bearing as a singler degree of freedom torsionally resonant system with damping. Because it's a good first approximation. The resonant frequency is determined by the platter moment of inertia and the belt compliance and damping is provided by the platter bearing lubricant and internal damping of the belt. For a given platter moment of inertia, a compliant belt will give a lower resonant frequency than a stiff one. Below the resonant frequency, motor speed variations are transmitted to the platter un-attenuated and above it they are attenuated at 6dB per octave. At the resonant frequency, they are amplified and their amplitude is affected by the amount of damping in the system. Normal practice is to place the resonant frequency somewhere where it won't be excited (with some reasonable damping), typically well below any frequencies that are generated by the motor so that they will be effectively attenuated. Re-engineering an existing system with a substantially less compliant belt may not give the results you expect.
If you really want to test this, take your tt belt, and apply a layer of scotch tape to the back or it. Did it help or hurt? You can peel off the tape.
The Measured Effects of the compared belts have been put onto another forum, by a individual who is a member of this forum as well and posts regularly.
Hopefully they pick up on this thread and can make more known about Mike's Belt, and if it to become a item offered for sale.
Hopefully they pick up on this thread and can make more known about Mike's Belt, and if it to become a item offered for sale.
Torque loading of the platter will stretch a rubber belt, reducing speed. Torque loading varies with current radius to the stylus, groove complexity, probably several other things. Using a stiffer belt and a heavier platter together can result in less speed perturbation without changing resonant frequency (assuming the bearing torque doesn't scale with platter mass and dominate over the stylus drag torque).
Lots of people seem to go for heavier platter and thinner rubber belt - this is not going to help with torque load, but will lower the bandwidth of the wow.
Adding viscous damped shaft coupler between the motor and pulley is probably a win too - don't think I've heard of this being done, but it might allow thicker belt without motor noise getting through.
Lots of people seem to go for heavier platter and thinner rubber belt - this is not going to help with torque load, but will lower the bandwidth of the wow.
Adding viscous damped shaft coupler between the motor and pulley is probably a win too - don't think I've heard of this being done, but it might allow thicker belt without motor noise getting through.
Hey DNic
It is kind of sad that no one read your post closely or could understand what you are looking for. If I read you post correctly you already know that tape sounds different belts most currently used. The Teres group was playing around with that 20 years ago. You might have been a part of that. I tried cassette, vhs, and 1/2, 3/4, 1 inch mylar tape. I also tried different splicing tape and angle cuts. I also used all different kinds of string, silk being my favorite. I also made various types of pulleys with different motors.
I never found a sweet spot. Adjustment seemed necessary quite a bit , tape splice would come apart after months of use. String was less of a hassle but maybe a little less solid. I also tried a rubber belt for grins and it was awful. Now it could have been it was pushing a 35 pound lead loaded aluminum platter.
So after reading alot about idlers I built a set which I could put on my motor pods so I could run it with tape or a idler pulley. About 10 min change time. This was a big win for me. More dynamic and full body sound without masking the detail. I used various types and sizes of orings and if one wears out pop on a new one and a quick grind, on a jig I made, and down the road I go.
Chances are you do not have a small machine shop so my solution for myself might be beyond what you want to do or can afford. Maybe a pre done solution for your needs is Galiber turntables in Colorado, one of the early participants in Teres group, was getting some high tech belts made for him. Might check him out. Not sure about your table and if sizing would be a issue. He should be able to tell you the sound difference between this belt and mylar.
Enjoy the ride
Tom
It is kind of sad that no one read your post closely or could understand what you are looking for. If I read you post correctly you already know that tape sounds different belts most currently used. The Teres group was playing around with that 20 years ago. You might have been a part of that. I tried cassette, vhs, and 1/2, 3/4, 1 inch mylar tape. I also tried different splicing tape and angle cuts. I also used all different kinds of string, silk being my favorite. I also made various types of pulleys with different motors.
I never found a sweet spot. Adjustment seemed necessary quite a bit , tape splice would come apart after months of use. String was less of a hassle but maybe a little less solid. I also tried a rubber belt for grins and it was awful. Now it could have been it was pushing a 35 pound lead loaded aluminum platter.
So after reading alot about idlers I built a set which I could put on my motor pods so I could run it with tape or a idler pulley. About 10 min change time. This was a big win for me. More dynamic and full body sound without masking the detail. I used various types and sizes of orings and if one wears out pop on a new one and a quick grind, on a jig I made, and down the road I go.
Chances are you do not have a small machine shop so my solution for myself might be beyond what you want to do or can afford. Maybe a pre done solution for your needs is Galiber turntables in Colorado, one of the early participants in Teres group, was getting some high tech belts made for him. Might check him out. Not sure about your table and if sizing would be a issue. He should be able to tell you the sound difference between this belt and mylar.
Enjoy the ride
Tom
That has been, and ALWAYS will be the issues with belt drives.
Wear, age, design, all take its toll eventually.
I never cared for belt drives, my first one was an AR XA... I sold it off quick.
And servicing hundreds of TT's in the shop reinforced my dislike for them.
Dual idler drives always pleased me, as do well-designed DD's
My Kenwood DD linear tracker (cheap) outdoes many esoteric fancy tables by a mile.
Can you use a polly v belt, but the plain side. These will have cords in them, I presume you can get them in smaller sections than washing machine belts. I guess you could also use the plain side of a small toothed belt, but even on the unused side the teeth could still induce some vibration.
Actually, there is an equation for the energy stored in a flywheel.
The purpose of the flywheel is to store energy and smooth-en out fluctuations.
Belt will not cause enough fluctuation in normal use, unless loose or whatever.
Again, I think everybody has not actually analyzed this problem.
The purpose of the flywheel is to store energy and smooth-en out fluctuations.
Belt will not cause enough fluctuation in normal use, unless loose or whatever.
Again, I think everybody has not actually analyzed this problem.
There are two flywheels; the plater and the motor, the motor may by small, but it's peripheral speed is most possibly higher than the rim of the plater. The cogging of the motor might not be too far away from the resonant frequency of the two masses and spring of the belt. Then you've got to make sure the belt doesn't act like a guitar string, who though gently turning a record would be such a complicated issue ?