Anti-Static Record Mat with Damping

Anti-Static Record Mat with Damping

Postby theeng » Sun Nov 15, 2020 5:15 pm

Note for those who go bare/topless, this discussion of a record mat is probably of little interest. I use a mat for the record and as much as protecting the platter (a Classic 2" thick aluminum)

Right to the point (discussion follows), I am testing a record mat material that is used for ESD Work Surfaces. The material is Bertech, ESD Vinyl Mats and Mat Kits, 3059 Series - https://bertech.com/wp-content/uploads/ ... t-3059.pdf. Amazon sells a 18"x24" piece for about $50 USD - https://www.amazon.com/Bertech-Three-La ... r=8-5&th=1.

The material is only 0.1" (3/32) thick but is 3-layers. The top is lightly embossed (gray or blue) vinyl that is formulated to be dissipative, the bottom is smooth vinyl that is formulated to be dissipative and the center is a conductive 'fleece'. The material is stiff (but not completely hard) with durometer of 85A so it has some damping, but can be cut with scissors. The center is electrically conductive. My platter/spindle is grounded (w/braided cable) to a wall outlet and with a DMM I measured 0.5-ohm between the conductive mat center and the wall outlet. But the mat surfaces being vinyl match the record material so static should not be developed, and any static on the record should be dissipated across the surface to the grounded spindle or through the top dissipative vinyl cover to the conductive center to the grounded spindle. Even though the platter shaft/spindle is grounded, any static charge that is conducted to the platter, the path of least resistance can be to the record if it is in direct contact (large surface area) noting that the platter bearing is lubricated which provide some insulation, and only the spindle is in direct contact with the platter. The top and bottom dissipative vinyl surfaces prevent triboelectric effect from the Aluminum platter to the record. And, any static charge that may be conducted to the platter from the EPDM rubber belts is dissipated by the mat to the platter spindle.

The mat material and use are not breaking any new ground; it just appears to be a good collection of anti-static and damping properties that follows previous practice.
Electro-Static Discharge (ESD) practices are pretty well accepted and widely documented. I address this in my paper Section VI and you can find lots of info on the web. The foundations of good ESD practices are ground all conductors and minimize insulating type materials. Unfortunately, the insulating vinyl record that is very negative on the triboelectric scale cannot be eliminated. There are any number of Triboelectric scales but the concept is materials with dissimilar charges in contact with each other can develop a static charge with the negative charged item collecting the charge. Buna-N or EPDM rubber in contact Aluminum ‘can’ be a source of static, and vinyl in direct contact with Aluminum ‘can’ be a source of static. As a general note, dissipative in ESD terms generally implies that static charge is dissipated slowly - generally within a few seconds. Dissipative surfaces are used to prevent accidental shorting of sensitive semi-conductors if they were placed on a conductive surface.

The article “Do Turntable Mats Work? You Bet!” in Audio Magazine June 1979 (download here - https://worldradiohistory.com/Archive-A ... 1979-06.pd ) goes into a good summary on the topic and no reason to repeat here and illustrates the flow of static charge and the benefits of damping.

The article “Phonograph Reproduction 1978” in Audio Magazine May 1978 (download here - https://worldradiohistory.com/Archive-A ... 978-05.pdf ) goes into some detail on static; what causes it and what does not – the needle in the groove was not source of static.

Some background:
For a couple of years, I was using a very thin (~1mm) leather mat – suede side-up/skin side-down that I cut from a remnant. However, I started to notice that side-two of the record was noisy and overall, the records were noisy. A quick check with a UV light showed my problem (see photo) – the mat was full of fibers and I suspect that once it had adsorbed - become saturated with fibers it began giving them back; and no amount of brushing or beatings was going to clean it. FYI – before this thin leather mat, I ‘briefly’ tried a store-bought thicker leather record mat – so much static developed that the record lifted the mat from the platter. So, the experience with the leather mat taught me I need to be more careful with cleanliness.

Earlier this year I tried the Technics/Panasonic mat PN RGS0008. This is a 3mm thick relatively soft rubber mat. It is likely manufactured from nitrile rubber (near neutral on the Triboelectric scale) because it did not attract dust/lint/particulate and any was easily brushed away. So, this mat met the cleanliness criteria. However, it so effected the acoustic performance that after a while I found myself listening more to my digital sources than my vinyl; and my vinyl source by design is supposed to be way better than my digital. The best way to explain the effect was that it softened and homogenized the music. It’s that soft focus that makes everything look (and sound) good; but takes away all the interesting details. So, damping by the record mat can have a profound effect. However, I now use this mat as a covering after play for protection from dust or any hard objects.

So, right now this Bertech, 3-Layer ESD Vinyl Mat, 3059 Series is kind of punching all my buttons – picture below (with 1mm thick leather washer to raise the record just a bit to get better clamping). Will it be as anti-static this winter when the humidity drops is TDB; but I like the acoustic performance so much, it’s a keeper either way. There are other single and two-layer ESD mats. Will they work as well – maybe? But, the Bertech, 3-Layer is unique it’s the only 3-layer and the only one I found that the surface is specified as being impervious to just about any cleaner so durability of anti-static properties should be very good. FYI – It comes rolled-up, and after cutting will take some time to fully flatten – I hastened the process with a Vinyl Flat at 110F; and I slightly undercut the spindle hole with a box cutter tip to make sure it had a good seal to the spindle. Also found that the mat makes a good base for the motor – just cut an appropriate circle or square.
Hope you find this of interest,

Best Regards,
Neil
Yeah – devil is in the details.
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Re: Anti-Static Record Mat with Damping

Postby jmcox » Sun Nov 15, 2020 8:14 pm

Hi Neil -

“The mat material and use are not breaking any new ground; it just appears to be a good collection of anti-static and damping properties that follows previous practice”.

The main take away (for me at least) from your post is an obvious one really - and I can't believe how lax I’ve been in that regard (!) - avoidance of dust and contaminants on the record surface left by the turntable mat itself.

But also this post is causing me to think about the various properties relating to static charge and dampening involving record mats. I have a few mats that I've used over the years, one of them being a product marketed by the name of “Mooo Mat”. Although it's not on my turntable currently, I did find the sonics pretty good - and in thinking about it the disparate properties (at least as advertised) of the mat might lend itself to the dual purposes of dampening and static charge avoidance (it was said that the natural cow hide itself had anti-static properties) - . . . Maybe ???
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Re: Anti-Static Record Mat with Damping

Postby theeng » Sun Nov 15, 2020 11:57 pm

jmcox,

There is some precedence with the acoustic performance of thin leather mats - https://www.6moons.com/audioreviews/hiraga/mat.html. As far as anti-static properties, leather is very dependent on hydration (moisture) status. The greater the moisture level which relates back to ambient humidity the better the static dissipation capabilities which favors thinner leather. Thicker mats which have a greater nap (on the suede side) can trap air and are always going to be more insulating. The Mooo Mat - https://www.musicdirect.com/analog-acce ... record-mat makes some claims that are a bit reaching, but the leather covering should have been very thin. As far as the anti-static treatment, this is generally accomplished by an additive such as a cationic surfactant that absorbs moisture from the air but these coatings are not permanent, can be ambient humidity dependent (often not so good <35%) and 'may' transfer. Otherwise, it sonics rated good - https://www.analogplanet.com/content/mats-unmasked.

I found that my thin dense leather mat (with no coating) mostly did not cause static - not sure of how effective it was at dissipating static; there were challenges in low humidity (<40%) and its damping would have been minimal. This 3-layer mat in some ways mimics the https://www.musicdirect.com/analog-acce ... latter-mat since the center conductive layer of carbon fleece can dampen vibration in a similar fashion while still being conductive.

Regards,
Neil
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Re: Anti-Static Record Mat with Damping

Postby jmcox » Mon Nov 16, 2020 12:58 am

"This 3-layer mat in some ways mimics the https://www.musicdirect.com/analog-acce ... latter-mat since the center conductive layer of carbon fleece can dampen vibration in a similar fashion while still being conductive."

:D

Coincidentally, that's what I'm using now . . . . . (the 3 mm version)
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Re: Anti-Static Record Mat with Damping

Postby Golear » Mon Nov 16, 2020 4:04 pm

Interesting article and material.

Static:
Very interesting info in the Audio article on static building up on both sides of the LP, and the side that is in contact with the platter gets its charge neutralized (if the platter has a connection to Earth) but the side that is being played does not! And that there can be static hotspots, and that this an affect the VTF!

So, drawing from the article, one has to rest the side that will be played down against the platter, and allow time for the static to discharge -- which can be a pain. This might point to using a brush of some kind -- either a separate one, or one integrated to the arm. A brush that is integrated to the arm might offer some opportunities for damping the arm. Or using the classic Audioquest brush on the side that's being played - not to clean it but to neutralize the static.

Or putting the LP in a "LP destaticizer". There was an "LP demagnetizer" for sale at a crazy price some time ago. This might have been some intentional obfuscation. I don't think it will be hard to put an LP into a destaticizer of some kind, would it? All we'd need to do is cover both sides with something conductive, that has a path to Earth. Extra credit: pass a high-frequency alternating voltage to both sides. Or white noise signal?

(I don't think I have a static issue with my LPs. It might be because of the relatively high humidity here.)

Damping:
The other part of a mat is the mechanical damping the LP and the platter. I guess this can be system-dependent. Very interesting options. I use two LPs as a platter mat.
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Re: Anti-Static Record Mat with Damping

Postby theeng » Mon Nov 16, 2020 4:56 pm

Golear wrote:Interesting article and material.

So, drawing from the article, one has to rest the side that will be played down against the platter, and allow time for the static to discharge -- which can be a pain. This might point to using a brush of some kind -- either a separate one, or one integrated to the arm. A brush that is integrated to the arm might offer some opportunities for damping the arm. Or using the classic Audioquest brush on the side that's being played - not to clean it but to neutralize the static.



Golear,

Audio June 1976 did state: "Interestingly enough, however, a high degree of conductivity in the mat will cause a migration of the charge between the upper and lower disc surfaces. This migration reduces, in large measure, the field on the upper surface." This may be weight dependent so a thicker 180 gm record may not work the same; nor will non-black records that have no carbon black pigment. However, the maybe 5-10 seconds it takes to discharge the record to the mat and then flip to play is probably not much different than the 5-10 seconds it takes for total time to use the brush - start turntable, grab brush, position & hold, put brush away.

Otherwise, the folks at the Vinylengine have found a cheap device that can quickly neutralize static charge - http://www.vinylengine.com/turntable_fo ... 593b933ec7 . I bought one - just in case - its so cheap - and I can always use it for just its intended function - https://www.amazon.com/RONXS-Upgraded-E ... 989&sr=8-1.

Regards,
Neil
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Re: Anti-Static Record Mat with Damping

Postby jmcox » Mon Nov 16, 2020 7:46 pm

Certainly more money, but I use one of these:

https://www.amazon.com/Furutech-Destat- ... s9dHJ1ZQ==
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Re: Anti-Static Record Mat with Damping

Postby Golear » Tue Nov 17, 2020 2:43 am

@theeng
Thanks. That Ronxs lighter looks very useful indeed.

Perhaps those of us who use the classic Audioquest brush should connect it to Earth, with a length of wire. That might be overkill but we're audiophiles.

PS: I just remembered, it wasn't an LP demagnetizer - it was a CD "demagnetizer".
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Re: Anti-Static Record Mat with Damping

Postby madrac » Tue Nov 17, 2020 7:32 am

I use one of those PC Deionizer fans to remove static from LPs. Don't recall where I got it - either Amazon or Ebay - for like $80.
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Re: Anti-Static Record Mat with Damping

Postby theeng » Wed Nov 18, 2020 12:20 pm

Golear wrote:
Perhaps those of us who use the classic Audioquest brush should connect it to Earth, with a length of wire. That might be overkill but we're audiophiles.



Golear,

FWIW - There are ESD anti-static carbon fiber brushes that are sold for industry that are designed to be earth grounded - complete aluminum handle with hole for ground wire and all carbon fibers are in direct contact with the aluminum handle. Cost is very reasonable - $24 for a 4" brush - https://amstat.com/anti-static-brush/ca ... r-brushes/, but I draw your attention to details that for static charge removal, the brush does not need to touch the surface and at best just kiss the surface.

One 'could' fashion a metal swing arm (with earth ground wire) with a 4" CF brush attached to remove static from the record, and then manually swing it away when removing the record - the brush would be positioned just 1-2 mm above the surface. In my mind this all too cumbersome, but as they say to each their own. There are similar type arms/brushes that ride the groove, but my opinion is that you want to stay out of the groove - you may remove the static charge, but the brush tips are going to sheer and leave debris in the groove. I have been researching the removal of particulate from surfaces, and I am just about convinced that for the small debris (<25 micron) that can deposit in the groove including diamond and vinyl dust - there is no way a simple dry brush is going to remove that debris. The attractive forces that hold the particles to the record vinyl surface are just to great to overcome with a simple soft dry brush.

So, I am taking a cue out of the technical paper THE WEAR AND CARE OF RECORDS AND STYLI, written by Harold D. Weiler, (Shure) written over 50 yrs ago - 1954. I am staying out of the groove. If I can establish a good clean surface and keep it dry and keep the top of the record surface clean, then the diamond/vinyl dust that will form from record play will be like very dry powdery snow. The stylus with its very high forces (1000's of psi/100's of G's) during play that can move the particulate will just brush them aside with no drag/effort and some will blow upward above the record and some will be pushed deeper into the groove away from the actual playing surface. But, if you use those wet pads as every play maintenance, then as Harold D. Weiler pretty much said - you risk developing an abrasive sludge.

Take Care
Neil
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