Replace VPI TNT rubber belt with nylon thread

Auy one tired replacing the rubber belt with non-flexible nylon thread on TNT turntable?

What are pros & cons?

Any sound improvement?
If you're even considering this then you need to have a speed controller as well. The different diameter of the thread vs the rubber belt will result in a speed difference on the platter.

Basically you need a non-stretch string, nylon or silk seem to work best. You will probably need to give the platter a starting push with the string. The sound difference / improvement is very noticeable. Better PRAT and detail retrieval with the string. Notes seem clearer and unsmeared.

If you don't have a speed controller you could try putting something heavy and smooth up against the rubber belt where it comes off the motor spindle before it gets to the platter. You just need to touch it enough to damp those nasty vibrations travelling along it.
I agree with Ptmconsulting completely. I am using 0.004" nylon string with SDS controller.

It sounds more detailed and clearler. Bass seems better defined. Sounds like high frequencies are better defined. It seems to have less bass, but bass is better defined. If your system is bright in the beginning, you may not like it.

I am going back and forth with this and still trying to find which way is better in my system.
Thanks to both. Advice is very helpful.

I use non-flexible nylon string with speed contoller. I find the speed is 6% faster with the nylon string. For the sound, I find it cleaner with less coloration (or less rubber belt sound), tone is more natural, image is 3-dimensional, bass is better defined and improve tonal balance a lot. Exactly what Sojs commented. The background sounds quieter and darker, probably due to more stable speed and no motor vibration is being transferred through the belt to the platter.

But I get small motor noise comes out from the motor spindle. I don't know why. Is the tension too tight? Can this be resolved? Really apprieciate is Ptmconsulting or Sojs can give advise.

The string shouldn't be overly tight. Just enough to keep the slack off and make the platter spin. too tight and it seems to constrict and over-control the platter. Let the mass of the platter do its thing.
I have the TNT with the single fly wheel. Should I try replacing just the big band or both?
Do both spans. The short length between the motor and the flywheel likes more tension than the platter span. Heavy cotton or poly thread requires a bloodknot; thicker silk requires a loop knot with the knot positioned to travel on the outside of the span. It takes a bit of practice to arrive at the correct tensions, but once there you won't go back.
I own a VPI Scout and my dealer recommended replacing the rubber belt with a silk thread when I was buying it. Since I don't have a speed controller, would you say it'd be pointless to do it and better to stick with the rubber belt?
You can't do it without a speed controller. The different diameter of the string vs belt will result in a major speed difference.

Here's a link to an on-line vendor for inexpensive silk thread in any color you may want. I recommend size or 3.

Griffin Silk Bead Cord. Link below for online supply:
I have an SDS. Thanks for the link!
Can the silk thread be used on a TNT2 with 2 drive belts that only touch 3 points on the platter ?
There was some regular 100% silk in the house. Thin stuff s303. I tried this out of curiosity. I got it to spin but it was too slow even when turning the speed faster with the SDS. Any thoughts?
may someone explain me how the ends of the nylon stick?
What ever I tried I always had a compote at the end which I think its not right.
thank you
When you put the string on a VPI table, it sounds closer, but not equal to a rim makes the same kind of upgraded sound, cleaner, clearer, more tuneful bass, etc.
Just for kicks I went out and got some elastic thread, as my prevoius attempts to use silk and nylon thread resulted in lots of slipping.

Why do I even want to try this? Purely for said kicks. I'm just plain curious to see if I can actually hear any difference between that and my VPI belt; will something with less friction and surface area sound any different.

So, does anyone know of an elastic thread material that is the same tiny diameter as, say, silk or nylon thread ? (And don't say, "Yeah, man, it's called a belt.")

The 'table is a homebrew, with a satin-finished 70mm platter; the motor is from an older TNT.

I have been using unwaxed dental floss for a few months and belive it sounds better. I do have to have it incredibly taught, thougg. Starts up w/o help, speed is dead on and no surface noise. I should go back to the belt to do an A/B but sounds sooo good and such a pain...
See dougdeacon's thread on mylar. There can't be any comparison between the two.
Mylar tape (even without the special treatment I described on that thread) performs far better than rubbery belts, silk thread, dental floss, recording tape, vcr tape, spiderweb fibers or anything else we've tried.

BUT, the motor's capstan and the platter must be suitably sized and shaped. The tape we use is 1/2" wide. Most TT motor capstans won't accommodate that. The platter should have flat vertical sides, no grooves or other irregularities.

Additionally, the motor will need very precise levelling (paper shims work). This wide, dimensionally stable mylar tape is completely inelastic so it provides a direct mechanical linkage with no stretch and very little slippage - which is the whole point. However, this leaves very little room for deviations. If the sides of the motor capstan aren't precisely parallel with the sides of the platter, the tape will crawl right off the capstan in just a few revolutions. That usually destroys the tape (which takes an hour or more to make).

Superb motor/platter coupling, but not for the faint of heart or for those who aren't adept at twiddling! ;)
I've found that four drive belts improve sound quite a bit over the use of one. I use the VPI dual motor single flywheel drive station on most of my tables the 4 long belts fits nicely above the two belts from the motors to the fly wheel.

Good Listening

Alas, my VPI motor has a V shaped capstan, so silk thread is all I can upgrade to. No mylar for me. However, the silk thread is a substantial improvement over the original rubber belt.
Shameless plug alert.
I can source the capstan if you are interested.
Thanks Don, but I'm not sure I can actually remove my capstan from my motor. I've tried before and I really think it is epoxied on. My VPI motor is very old.

I'm afraid to do this properly I would have to buy a second motor, and I really am quite happy with the silk thread.
The old VPI pulleys were pressed fit onto the shaft. If you put your motor into a freezer, the metal motor shaft will shrink more than the delrin pulley, therefore, easing up the tension.
Ah... cryo treatment. Another great tweak!
Doug, what issues did you have with string drive silk thread and dental floss. Did you spend much time with either of those or was it quickly obvious vs mylar tape?

Thanks, TD
Years ago when the belt on my Aries broke I replaced it a double strand of 4 lbs test fishing line. I had to change the SDS settings but it runs like a champ. I have a super heavy clamp so I do give it a little push at startup.

Too lazy to try anything else...

You guys are describing why I gave up on belt-drive turntables entirely.

I don't understand your post. I set it up once over three years ago and a little push on a 1080 gram wright is no big deal. I not suffering at all, so what's your gripe and it's solution?

I have no gripe; as noted, I switched. I was only trying for a bit of levity. If you read what others have posted here and elsewhere about fussing with belts of various kinds, I hardly think you can deny that the belt per se is bothersome if one is a perfectionist. I do apologize, because my comment was OT.