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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
jfd01
32 posts
 
Well I finally opened last night my new bottle of Etchall to remove the silver layer of my mylar belt (Galibier Serac), following the procedure outlined above by Doug--except that I was working with an already-made belt. I then did several listening passes, with different LPs, alternating the "cleaned-up" belt and a brand new one with its silver layer still in place.

Here is the list of the recordings I used for comparison:
- Vivaldi, Four Seasons, Fall, 1st mvt, Kuijken and La Petite Bande
- Beethoven, String quartet op.127, 1st mvt, Quartetto Italiano
- Stravinsky, Firebird, Infernal Dance of all Kastchei's subjects, Dorati/London Symphony
- Mahler, Symphony n.7, beginning 1st mvt, Haiting/Concertgebouw

So, a good range of ensembles and recording difficulties. In all cases, most noticeable were:
more extension in high register; much tighter bass, with better pitch definition and spatial localization; better sense of perspective in depth; slight recess of mid-bass range, giving a somewhat better separation between instruments (this one threw me off at first because it sounded like less body; but after some time I realized what was being gained rather than lost).

This has got to be one of the most spectacular tweaks I've experienced recently!
Thanks Doug and Paul, for your pioneering efforts!
Cheers.
dougdeacon OP
3,338 posts
 
Thanks for the report Jfd01. :-)

Good job hearing through the trick of flabby mid-bass that gives an impression of body but masks the texture and overtones of real bass instruments. The greater extension in HF's is, I think, due to more stable platter speed and lack of slippage: the tiny waveforms above 15K are easily lost if everything isn't "perfect". Pitch definition is of course dependent on platter speed, and the more pitch-sensitive your ears the more critical this aspect of TT perfomance becomes.

When you said you planned to etch an existing belt (rather than unspliced mylar) I worried about the stability of the glue. No problems there, apparently?

dan_ed
2,451 posts
 
I finally got around to trying this over the weekend. This is a wonderful tweak and I give it the two key lime pie award! I believe this is getting us close to the realm of direct drive, at least as good as an idler.

My perspective on the improvements are similar but, since I listen to mostly rock (a little flab in the bass is not a bad thing), I thought I may have noticed things differently. But I've had some time to digest this overnight and I don't think I would disagree with anything anyone has posted about this new belt configuration. What I've noticed the most is the increase in micro-details. I'm hearing new sounds in the background and around the edges. Bells, wood blocks, chimes and such are not being smeared anymore so they come out to the front. The attack and presence of all instruments is greatly enhanced. I hate to use the cliche about veils being lifted, but there it is.

I found the process of etching the belt very easy. HINT, is it always the side that the mylar wants to curl to. The thought did cross my mind about trying this with an already spliced belt, but the worry of what happens to the splice tape prevented me from trying that. So I simply cut the old splice out and proceeded. This led to a belt that is about 2" shorter than what I normally use, and I'm left pondering if shorter isn't also better. This means that the wrap around the motor capstan isn't as tight so the belt runs smoother. There seems to be no chance of belt flutter with the shorter belt. With the increase in friction provided by the de-mylared surface I suspect that an even shorter belt may work better.

My belt may not be as tight as what Doug gets. I say this because I'm pretty sure I'm no where near tilting my Galibier's motor. I found that there is a point where an increase in tension causes a noticeable thump when the splice went around the capstan. So I backed off to the point where the splice was barely audible with no music playing. That should be good as I find the splices to relax a bit after running for several hours. There is still more tension than I ever ran with the stock mylar.

And that leads me to my only complaint. It is too bad that splice tape comes in beige and not clear! Watching that splice go round and round is disturbing, but I can learn to live with it.
jfd01
32 posts
 
Doug,
No problem with the splice so far. It hasn't moved.
Like Dan, I'm running the belt with a bit more tension than before, but not near the motorpod tipping point.

I also agree with the increase in micro-dynamics, as it dawned on me while listening to Stockhausen's orchestral piece, Inori (SWF Orchestra, DG). In this piece, Stockhausen created a "scale of dynamics" with 60 degrees, from almost silence to very loud (by varying the mixture of instruments and dynamic indications); there's also plenty of complex attacks and subtle resonances throughout to test the resolution of a system; and it's recorded with beautiful perspective in all dimensions. Plus, it's a great piece of music...
Cheers.
frank_sm
111 posts
 
I've always had problems with the belt "stretching" at the spliced area so that the adhesive area of the splice becomes exposed after only a few hours of playing. This exposed area becomes larger as time goes by and the larger it gets, the more noticable the sound as it passes by the pulley.
Is there a know splice material that outperforms all available? That is my main gripe with mylar tape, the stretching.
I haven't yet tried the method Doug outlined in this thread but I'd like to, only if I can find a solution to the stretching of the belt at the splice point. Any ideas?
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