2. analog
  3. 1215361521

Upgrade for users of 1/2" mylar belt

This thread will be of interest to Galibier, Redpoint and Teres belt drive TT owners, or anyone using or thinking of using a drive belt made from 1/2" mylar. The belt material of choice on these tables for several years has been the silver holographic mylar streamers from sources linked on the Teres and Galibier websites. This outperforms everything else we've tried but like anything it's not perfect - and we've now found something better.

One of the silver holographic mylar's assets can also become a liability. That metallic layer, when new, gives the belt exceptional "grip" on the platter and motor capstan. Minimal slippage on transients is one reason the material works so well. Unfortunately, that layer can wear over time, leaving a silvery gray residue and allowing performance to deteriorate. The only solution has been a good cleaning and a new belt. No big deal, but if there was a better or more stable belt Paul and I wanted to find it.

I'll spare you a recounting of our many experiments and jump to the good news: thanks to (yet another) brainstorm by my resident genius/partner, we've developed a belt that both performs better and lasts longer. I've held off posting until we were sure, but after 4 months of steady use Paul’s idea is still working perfectly. The only negative is that making this new belt takes an hour or more of work spread over two days, but to us it's worth the effort.

HOW TO MAKE ONE

1. Cut a length of the silver holographic mylar tape sufficient for your TT, plus 3-4" extra.

2. Remove the silver metallic coating off the backside of the mylar. Paul used an acid etching cream popular with stained glass hobbyists to dissolve the metal - safe, quick and easy (use skin and eye protection).

3. Rinse thoroughly under running water, inspect to make sure you got all the silver off, wipe and hang to dry overnight.

4. Splice as normal to make a TT belt, making sure you tape on the OUTSIDE (which will be smoother than the now bare inside).

5. As always, the best splicing technique is to overlap the ends and cut on a 30-40 degree angle. Apply 1” video splicing tape (*not* tabs) across the belt at the *same* angle and trim away the excess.


WHY IT PERFORMS BETTER

Unlike any plain mylar ribbon you could easily buy, the silver holographic streamer has an ultra fine texture embossed on the back side of the *mylar* during manufacturing (*before* the metallic backing is applied). Once the silver layer is applied you can't see this texture, but that's what diffracts light like a million tiny prisms to produce the shimmery rainbow effect. Stripping the metal backing away exposes this texture, which becomes the contact surface of your new belt.

Paul realized this texture must exist and then hypothesized that using it for the working side of a TT belt might provide more “grip” on the platter rim and motor capstan than either plain mylar (which is extremely smooth) or the metallic backing. He was right. This belt produces more lifelike dynamics, both macro- and micro-, than even a brand new silver holographic belt - which heretofore was the best.

WHY IT LASTS LONGER

Removing the metallic backing exposes bare mylar, which is much sturdier than that fine layer of metal. Under normal use and assuming no accidents, one of these belts should last many, many months, perhaps years, while delivering consistent performance. Ours is going into its fifth month with few visible and no audible signs of wear.

Different motor capstan materials might interact with this belt differently, but I urge anyone with a compatible table to give this a try. Like all our favorite little tweaks, we'd find it hard to go back.

A FEW TIPS

1. Clean any silver/grey residue from your old belt off the motor capstan and platter before mounting the new belt.

2. As many of us have learned, the more inelastic the belt, the more critical motor leveling becomes. That is truer than ever with this new belt. Getting the motor set just right is touchy. Take care that your new belt is riding level in the center of the capstan before you start to play. You don't want it sliding up or down and mangling itself.

3. Motor distancing is also more critical than ever. Since this belt will not slip *or* stretch, tension must be perfect. The right amount is just shy of the tension that would tilt the motor off its feet.

4. Depending on your climate, the belt can build up static potential during use. Not enough to spark, but more than enough to attract airborne dust. I dust the belt's inside with my CF brush after each side before stopping the platter.

5. With this or any belt, always start your platter spinning with a helping push. Just pressing the motor's ON button creates lots of belt-wearing friction as the rapidly spinning motor tries to drag that heavy platter up to speed.

It all sounds like a pain, and it is! But the sonic and longevity results are worth the effort.

Cheers,
Doug
dougdeacon
palasr
528 posts
 
Doug,

I think the Kapton belts run truer around the pulley, resulting in better overall speed stability. In general, any splice will result in some small runout error causing the belt to slightly oscillate up and down the face of the pulley - the Kapton belts solve this nicely. And while I don't have a table in front of me with various moduli of elasticity, I think Kapton is more rigid than Mylar resulting in tighter coupling, less stretch, less loss. Also, remember that we use totally different controller architectures, as well as pulleys, so YMMV. Finally, they couldn't make spliceless Mylar belts, or I would have compared both materials.

Dave4u,

Since I'm the one who began exploring the Kapton alternative, I used this company: Blue Lake Products (http://www.bluelakeproducts.com/). While I haven't done any follow up business with them, I also don't know why Thom didn't include them in his list, however knowing Thom, I'm certain he vetted all the suppliers in his list. You can certainly give him a call and ask.
thom_at_galibier_design's avatar
thom_at_galibier_design
729 posts
 
Hi all,

Thom here … I haven't logged much forum time in the past 18 months as the Eiger project has been all-consuming. I'll try to hit on a few salient points …

Doug: I agree with you about belt traction. Last year's new drive system employs a much higher torque motor (significantly so), and this permitted use of a much wider pulley (approx. 1.3" diameter for lower gearing). This had the effect of significantly increasing belt traction. We're still playing with alternate materials (current one is stainless, but we're playing with a two-piece assembly).

Palasr: the missing Blue Lake link was an oversight. I just updated the Drive Belt page you referenced above.

Audiotomb: Thanks for the kind words. I realize your post above is from January, and you likely read my newsletter from two weeks ago about the shift back to "plastic" (Mylar/Kapton) belts.

One of the benefits of customers like Palasr (who are inclined to experimentation) is that they keep you honest and frequently beat you to the punch (with the Kapton in this case).

I have to confess that I fell in love with these woven belts - especially due to their robust construction. I'm a big fan of "robust", but in this case, it was a bit over the top. I found that the increased mass was transmitting noise into even a Stelvio platter.

One thing to note about Kapton is that while sonically it's Mylar's twin (far more alike than different), it's much more durable than Mylar. As Palasr pointed out, they're the drive belt of choice for flight recorders in commercial aircraft (the "black boxes"), which is pretty much a "no fail" application. You can still put a "crinkle" in one of these belts if you're not careful when installing them, but apart from that, they show promise of a long life.

For anyone contemplating a belt change, take note of any change in thickness from your current belt because it will affect how fast your platter spins. Depending on your turntable's design (adjustability) and the thickness of your current belt, you may have to take this into account.
With the shift from the .035" fabric belts back to Mylar/Kapton (.002"), I had to update the support page with a calibration procedure for the controller - a whole page to tell you how to twiddle two screws.

This effect on platter speed is counterintuitive, but I can get into the physics in a follow-up post, if anyone is interested. I'll try to catch up on the last few years' posts in this thread as well, and may have more to say on this topic.

Cheers,
Thom
thom_at_galibier_design's avatar
thom_at_galibier_design
729 posts
 
I updated my support page based on feedback from my customers. I left all of the links on the Drive Belt page, but noted where some of the manufacturers have placed minimum order quantities.

I'll start inventorying them soon.

Cheers,
Thom
george_a
34 posts
 
I am very interested in trying Kapton belts.

I telephoned A2Z as listed on the Galibier site. They require a $150 setup charge and $800 for 10 belts. This was for seamless 2mil Kapton. They do not do 1mil Kapton. They said making true seamless belts is difficult, not to be confused with welding or splicing, which will leave a feelable join.

I telephoned Blue Lake but have not been able to get past the answering machine, so I requested a quote via email. Pulsar mentions his cost at Blue Lake was $50 a belt, but Galibier states they require a large minimum order.

I also requested a quote via email from Belt Corp.

Would love to hear from Pulsar or anyone else that has had experience ordering seamless Kapton belts.

BTW AJ Conti (Basis turntables) has some interesting information regarding his quest for the ultimate belt. He ended up grinding his own rubber flat belts to a thickness of 0.015" and a uniformity of 0.0001". He believes uniformity is the most important speed parameter and thinness is desirable for isolation. Sounds like Kapton should be even better.
thom_at_galibier_design's avatar
thom_at_galibier_design
729 posts
 
Hi all,

I've been too engaged with the Eiger to look into this. I suspect that these companies thought they were doing a one-off and made belts for a few folks like Palasar. Then, they started receiving a flood of requests and realized that these "ones-ies" were a distraction from their main business.

I'll look into quantity pricing in the near future. BTW, you want at least .002" thick. .002" works well, but even as durable as Kapton is (relative to Mylar), I'm curious about .003" thick belts.

I'd be tempted to reduce the width to keep the overall mass the same (energy transfer to the platter) - reducing it to perhaps .375" wide. With my wide pulleys (approx. 1.3" in diameter), there's plenty of pulley surface for traction - slippage reduction.

I'm not sure how this .125" reduction would work with a skinny pulley - the sort we used to use at Galibier. I'd be tempted to stay at .500" wide if I were running a skinny pulley.

AJ has some excellent information in his treatise on belts. Of course, he's looking to optimize what I view as a lossy system - a stretchy belt.

Now, if everyone made the same product, it would be a boring world, wouldn't it?

Cheers,
Thom @ Galibier
More to discover