Some thoughts on dust covers

The he question is at what point do you replace the DC? After your listening session or during play?

Elliot is such a nice guy that he worries about my and your tonearms as much as he worries about his own. Elliot, stop screaming and come back into the room.

If you put together the paragraph that RB quoted from Antinn’s tome with the information that at least some significant fraction of dust is dead skin cells, you might surmise that although dust contains dead skin cells, they are not prone to lodging in LP grooves.

Dwette , yes I thought $60 was too much but I was in a mental hurry. “Double IPA”? My son in Tokyo loves IPAs but can’t easily find them there. I don’t love IPAs, on the other hand. I do need two more platter covers, so thanks.

You can buy lucite platter covers that have a hole for spindle and handles for lifting and placing for about $60 each, somewhere on the internet. They protect the platter nicely.  

These days, I advise wearing an N95 mask in any airport and on any airplane. You not only reduce your chances of COVID but also influenza.

Sadly, undecillion hadn’t been approved during my clinical training years. Then I went into the lab and never came out.

Undecillion is also used when penicillin doesn’t work.

Googled "what is the composition of dust".  Found this on the Martha Stewart page: "But there is one important myth to bust: While dead skin cells certainly do make up part of the dust in our homes, it's not as big of a portion as you may think. Sean Parry of Neat Services notes that people often assume that more than 50 percent of dust comes from dead skin, but in reality, "most of that is carried away by water when we bathe, ending up not on our floors, but in our sewers." '

I have no dog in the fight.  I am a dusty nihilist.

I can't resist. Too much idle time. The equations of Newton and Coulomb are quite adequate for considering the situation at hand.  You used their constants yourself as a basis for your statement about the relative magnitude of the two forces. No need for a unified theory here, which anyway does not exist. The reasons that your blanket statement about the relative strengths of gravity and electrostatic charge does not hold water are at least two-fold: (1) The units of the gravitational constant and Coulomb's constant are different. You cannot just assume that a numerical ratio between two different quantities is meaningful without considering the units (apples and oranges), and (2) in one case the objects are considered only for their mass (Newton) and in the other case the objects are considered only for their charge (Coulomb). I would say yes, in some cases the ES force can be greater than the gravitational force.  In other cases, no, gravity dominates.  It depends upon mass vs charge. One other difference between gravity and the ES force is that gravity is generally a force of attraction between two objects, whereas the ES force can be a force of repulsion, when the charges are alike in polarity, or attraction, when the charges are opposite in polarity. (Yes, I know about the question of whether the reason the universe is expanding means there is a repulsive form of gravity caused by dark matter, etc. But that is not an earthly problem.)

RB, to the question contained in your last paragraph, my current opinion, open to change if presented with contrary data (not a “belief”), is based on my data, the testimony of another Forum member who’s done the experiment many times before me with his own meter, and on the Shure Corporation white paper. You can buy a decent ES meter on eBay for less than $200. Why don’t you buy a meter, make some measurements, and then we can discuss. Don’t come to me with “Google AI” and no actual data or a reference to someone else’s actual data that is publicly available. The concept that the diamond on vinyl causes static charge is repeated over and over again in advertising for anti static devices, in audio forums like this one, etc. So it does not surprise me that Google AI believes it. I insulted you earlier,so I’ll forgive you for insulting me. If you want to go into detail about ES force vs gravity force, probably that would bore everyone else. But it’s not relevant.

Wyoboy, sorry I over-reacted.

The ES force is determined by Coulomb’s law, which like Newton’s equation for the gravitational force is an inverse square law. Both forces are inversely related to the square of the distance between the two objects under consideration . The difference is that the ES force is directly proportional to the product of the two charge quantities, where gravity is directly proportional to the product of the two masses. So I couldn’t make sense of that flat statement.

Richard, please get over yourself. I did believe what Shure wrote because of who they were, a company with high integrity and a scientific approach that they adhered to by backing up the majority of their information with decent experiments and by reporting the data therefrom. Did you read the paper? I actually bought the meter not only to do the experiment but mainly to measure the charge on my ESL diaphragm in the first place. So since I already had the meter, I used it for the purpose described, with results described. If you doubt me, buy or borrow a meter and do it yourself. But don’t infer I’m a liar or that Shure corporation are unethical. I also have to ask what would be my motive to deliberately post false information here? It makes no difference to me whether the stylus does or doesn’t cause static charge. I think what’s going on here is that you hate being corrected. Believe me; no one cares.

Other reasons I bought the meter. (1) it seemed like a cool thing to have, and the other guy on this forum who did the same experiment many times with the same results told me where to get it. I have a weakness for gadgets, and 2) I’m a scientist and insatiably curious.

Dover is correct that Shure do not describe the experiment that led to their saying static charge due to the stylus is negligible. My own frustration with that lack of detail is what led me to buy a static charge meter and do the experiment myself. The meter also shows me the zerostat works.

Dear RB,

Googles AI is full of.... baloney as regards bullet number one, and the whole business of AI is scary, because we tend to believe ""AI" and AI is nothing but a computer that scanned a bunch of opinions put into print by humans, and humans are still faulty.  Shure did the actual experiment.  I repeated it and so too did another person who regularly posts here.  He and I got actual results that agree with the Shure publication.But like I said, do whatever you want.

"The human body is normally a great drain for static."  Where do you get that? Static charge is nothing more than an imbalance of positive vs negative ions sitting on the surface of an object. In other words, it's a phenomenon of surfaces. So it is probable that if your body is charged up, because for example you are wearing leather soled shoes and you walked across a wool carpet before touching your LP, you might charge up your LP the instant you touch it. (Let's say your surface becomes negatively charged and touching the LP pulls positive ions off the vinyl surface to neutralize your own body surface, leaving negative charge on the vinyl. Vinyl is near the bottom of the triboelectric table [see for example the article on the triboelectric series on Wiki] and dry skin is at the top. This means skin "wants" to give off charge to vinyl.  There is much that is unknown about the electrostatic charge phenomenon, and the triboelectric series and table are only crutches.)

Your "TAS-recommended" AudioQuest carbon fiber brush is nice but far far from a perfect guarantee of a charge-free LP; I own one and use it before every play while grounding myself. It does not work all that well to prevent static charge build up, which in the case of vinyl is an excess of negative ions on the surface of the LP.  Of course, pulling an LP out of its paper sleeve is another important cause of the static charge on LPs, as I mentioned 3-4 posts ago; it's what I did to create a positive control for my experiment to see whether the zerostat worked and whether the stylus tracing the LP is a cause of static charge, trying to repeat the Shure experiment. The speakers in my basement are Beveridge 2SWs. You can categorize them as "electrostatic" but in fact they are a unique design in that there is no charge on the membranes in the resting state.  There is no external high voltage bias supply as for every other ESL.  So, no dice. On the other hand, the Sound Lab 845PXs in my living room are conventional ESLs, and yes there you have to be wary of their collecting dust on the diaphragm. "Shredded skin" does not strike me as an important cause, if it is any cause at all, of dust, unless you keep 30-40 people in your listening room. Maybe you were trying to be funny.

Wyoboy, I feel compelled to correct incorrect information that falls within my range of knowledge. Ideally, the information on this site should be as accurate as possible, because some of these posts are read and believed by newcomers to the hobby. For example, that is why I posted to correct RichardBrand’s statement that the stylus rubbing on vinyl causes static charge. You can call me a pedant or some other pejorative term because of my compulsion to be an intellectual policeman. Maybe I deserve it. I don’t claim to be infallible, and I always welcome correction; I have certainly been wrong many times; I only know that because others have seen fit to correct me. But that way, I learn too. The question for me is why do you care whether or not I post here?

dwette. I too use lucite (acrylic) dust covers that just cover the platter surface, like yours, on my Technics SP10 Mk3 and on my Denon DP80. My Kenwood L07D was sold new with exactly that type of cover, and I use the original Kenwood version on my own L07D. I need two more, one for my Victor TT101 and one for my Lenco. They are in my basement system. For some reason, the finished room area in my basement is amazingly dust free, maybe because the few windows down there are sealed shut.

"Prima facie it seems that when you played your record, it doubled the charge" First, 0.1kV to 0.2kV is a range where the meter is not very accurate and readings are not very repeatable.  The meter never reads zero, for example. So the difference between the two readings may not even be statistically significant.  Second, like I said, it is much more likely that my touching the LP had more to do with the difference, if it was even real. Third, such a low amount of static charge is inconsequential even if real. The problem we are addressing has to do with charges far in excess of 100V (0.1kV). 10kV (or 11kV in the specific case I noted) is 100 times higher 0.1kV. Do you have a background in this field, or are you a physicist or other scientist? If so, feel free to point out the error in my thinking. Since you don't have access to my meter, you could not have known its quirks, so I don't mean to criticize you for that.

I don't know why you compare "electromagnetic force" to gravity. First, the magnitude of the difference as you express it has no meaning unless you know the relevant parameters for the source of the EM force, in the case of EM, and the sizes of the objects that experience gravitational attraction and the distance between them, in the case of gravity. But also, electrostatic attraction is not identical to electromagnetism. The point about the Zerostat is only that if used properly it will reduce the charge to a harmless level. And it costs a lot less than most of the modern alternative gadgets.

Some flat earthers maintain that what we experience as gravity is due to electrostatic attraction. They have to resort to such an explanation, because if the earth were flat, it would not be massive enough to account for the gravity we do experience.

In my informal "experiment", I first yanked an LP from its paper sleeve (in order to be sure it got charged up) and measured the charge on one surface, 11kV.  Then I treated that surface with my 40 year old zerostat and measured the same area again, 0.1kV.  Then I played the LP and measured the same area yet again, 0.2kV.  That is the definition of "negligible".  And the very small increase in charge density may well have been due only to my handling of the LP after playing it. However, you are not alone in your previous belief that the diamond stylus rubbing on vinyl causes static charge.  Several makers of the very expensive static charge removal devices (not the relatively cheap Zerostat) parrot this belief in their advertising brochures.

Stylus rubbing on vinyl is not a cause of static charge. This was shown by Shure Corporation in their published white paper on static charge. I and some other guy here who also owns a static charge meter have repeated the experiment with the same result. No cigar on that idea.

My position has been stated twice already. I use no dust cover during play; I completely remove the cover, if the TT has one. But I advocate that each of us should make his or her own decision. My practice is based on my listening tests and my subjective opinion of what sound best. I do agree it’s a fine idea to cover the TT when it’s not in use. For the past many years I’ve had 5 TTs up and running with 6 different tonearms and cartridges, 3 TT s feeding one system and two TTs feeding another separate system.

I guess that is "yourlogic".  Unfortunately or fortunately, we are not all living in Fuller's geodesic domes. Another prediction of his gone awry. But it interests me that you can read what Elliot wrote about dustcovers vis a vis turntables and in any way conform that thought with Buckminster Fuller's thoughts on anything. The only way I can see that parallel is if you take the dust cover as a modern innovation, which of course it is very much not.  Far from it. It is rather more accurate to say that progress in turntable development has included the gradual elimination of dust covers.

Not that I care much, but what do the last few posts have to do with dust covers?

The zerostat works, but what it does is to reduce static charge, not magnetism. Static charge develops on every LP when it is handled because vinyl is one of several materials that easily accumulates an excess of negative ions on its surface.  The magnitude of the negative charge can be great enough to dramatically attract the cartridge, increasing the effective vertical tracking force of the stylus on the LP, causing distortion and even damage. This of course is a pull on the cartridge in the opposite direction from what you observed with a lucite dust cover that got charged up and then discharged.  In that case, the charged cover was exerting an upward force on the cartridge. LPs get charged up when you remove them from a paper sleeve or when you touch them with your finger tips after walking across a wool carpet, for examples.

I don't know why I keep posting on this, because it is one of those questions where every one of us is already convinced of the efficacy and rightness of his or her current practice.  We are all pretty much old farts and set in our ways.  Suffice to say, what I have already said, anything anyone else wants to do is fine with me.  I am operating based on my own past experiences, and so probably is everyone else. But please please don't accuse others of (1) not having a system good enough to hear what you hear, or (2) being a Philistine and so able to tolerate the horrible problem that you have seen fit to prevent.

Like Bill mentioned in his OP, of course there is such a thing as acoustic feedback that could in the worst case affect the cartridge, but the cure for that is to move the TT or the speakers so as to prevent the phenomenon. Furthermore, as I mentioned earlier, acoustic feedback of sufficient magnitude to affect the cartridge is also going to energize the massive undamped dust cover with possibly worse consequences. No experiment is necessary, ltmandela.

To my reading of it, the OP is not asking a question; it makes a statement.  To wit: "So the often offered extremes:  a) Always play your records with the dust cover down, or b) put the dust cover away in it's box and never use it, should both be recognized for what they are are - not solutions at all.  First principles:  Identify the problem(s), seek solutions and alternatives, prioritize."

That reminds me of Mike Myers SNL character, the lady on the apocryphal NYC radio show, "Coffee Talk", who would pose an issue without an opinion, and then say "Discuss". Predictably, that is what has happened here. Bill left off the obvious third option, which is to use the dust cover only when the turntable is not in use, and that too has been discussed. I wager no one's opinion has been changed.

I think you’ve made your position clear. “Exposing the record for the least amount of time is paramount “, for which you awarded RB one point, to zero for all other opinions. So what more do you want on this boring subject?

Elliot, I don’t think I’ve ever seen a square-shaped flat screen TV before now. Happy new year.

So I have a question for those of us who advocate using a dust cover during play, for the primary reason to avoid the accumulation of dust. (The acoustic argument is different, I think.)  Let’s assume we all agree there is some sense to using a dust cover when the TT is not in use. Presumably, that keeps the area under the dust cover free of dust during those periods. Furthermore, when you remove an LP from its sleeve and place it on the now uncovered dust free platter, we can have reason to believe that the LP playing surface is also free of dust, relatively speaking. Then most of us use some sort of record brush prior to play, and some of us take steps to reduce the static charge on the playing surface, which would go further to delimit the possible accumulation of dust during play. Moreover, it takes about 20 minutes to play one side of a 33 rpm LP, so the net exposure time to the environmental dust is about that long. Do you in the dust cover user during play camp suppose that in the course of 20 minutes, the LP could possibly accumulate enough environmental dust to cause ticks and pops (presumably that could only affect the innermost grooves, since they would be exposed longest to the air before being "read" by the stylus) or to otherwise damage the LP? Even accounting for the fact that when you set the stylus down on the outermost grooves, the LP is likely to be "clean"? And finally, what do you think happens to dust in the air that you trap over the LP surface, by the very act of using the dust cover? At least with no dust cover, the airborne dust has a chance to pass harmlessly across the LP surface and land somewhere else. Once the dust cover is placed, the airborne dust has nowhere else to go but the LP surface.

The ELP is not immune to dust, IIRC. TJ, if you want to come over and digitize my 3000 LPs, you’re welcome if you bring the necessary gear.

.."My deduction was that ambient sound feedback from the listening room and speakers is significant and audible.."

But it's fair to say that you don't stomp around and shout out while actually listening to music. Nor do you use a buzz saw, etc. Chances are you are sitting quietly when listening to music, so your experiment only demonstrated what we already know, that a cartridge is a transducer and as such can act weakly as a microphone, converting ambient sound wave energy into an electrical signal just as it converts wiggles of the stylus into an electrical signal. Now consider the opposite case which very much does pertain to the actual use of a cartridge: Have you ever stood near your TT and heard low level music signal emanating direct from the headshell? Most of us have observed that phenomenon.  When you play an LP with the dust cover lowered, it is possible that the low level music signal emitted directly from the cartridge can bounce around the inside of the dust cover  and feed back on the desired work of the cartridge, causing distortion.  Also, ambient sound in the room, minimal though that may be, will cause the dust cover itself to vibrate, since its horizontal top surface is like a drum skin. That too can be picked up by the cartridge.  In any case, whether these issues play into it or not, I hear what Noromance hears, and I concluded long ago that I don't want the dust cover anywhere around the TT when I am listening. (Raising the cover on its hinges also has its issues, since then the cover presents as a sort of reflector.) But I still recommend that you decide for yourself.

There is no correct answer. No corporation or engineer can give you the correct answer. Do what makes you feel good, but I’d advise against scolding others who do not see the issue in the same light as you (meaning any of us).

Here comes a bunch of comments and testimonials about dust covers, up or down, good or bad. I only suggest that each individual needs to try it both ways (or each of the 3 possible alternatives, up, down, or off the turntable during play). As I’ve written many times, I am in the last category based on listening tests, a purely subjective judgement.