Some thoughts on dust covers


Over the course of time there have been many discussions concerning the subject of dust covers.  They tend to revolve around the central question:  Should the dust cover be down or up while playing records?  Some of these discussions have been nasty, consequently I have refrained from participation.  It is hoped that I can provide some common sense that was given to me by someone of unquestioned authority many years ago.  During college and after, from 1970 to ~1980 I worked in HiFi retail, selling high end lines of audio equipment.  One of these lines was Thorens.  Sometime around 1977 or 1978, if memory serves, Thorens introduced their new TD126, as a top of the line TT with their own arm and I sold the first one at our store to very good customer.  He came back very unhappy after the first night of frustration with it.  The problem was that with the dust cover closed some of his favorite records were hitting tangentally on the very back were the platter came closest to the dust cover when it was in the closed position.  I called the manufacturer's rep and he set up a three cornered phone call with himself, the Chief Engineer of Thorens at the time, and me.  I don't recall the man's name, but it doesn't matter, it is what he said that matters, then and now.  The Chief Engineer explained that the problem was caused because the hole in the offending records was slightly off center so there was an eccentricity as such a record rotates about the spindle.  The solution was simplicity itself, the dust cover should be removed always when playing records.  That the intent of the cover is to protect the turntable when not in use.  I pointed out that we lived in a semi-arrid environment (San Diego, CA) which is dusty to which he replied that if the environment was too dusty for records it should also be considered unhealthy for people to be breathing the air.  He recommended are filtration, not dust covers to address environmental concerns.  The rep asked about air bourne feedback from speakers and the Thorens guy laughed and said that if that was a problem in a given system, relying of the dust cover was a very flimsy and ineffective solution and that proper measures should be instituted to provide meaningful distance and isolation to ameliorate the problem.   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.

billstevenson

Since when are we taking anything Google's generative AI has to offer as an authority?  Frankly lewm's reference to the published work of Shure years ago is an established, credible resource and those who disparage it must be doing so only because they have not taken the time to read it.  Shure's published work has always been of the highest order and commands the respect of the entire industry.  This is not a fly by night outfit only out for the fast buck.  Google on the other hand...give me a break.  After we get done talking dust covers to death, if anybody is left standing let's talk about the good old Dust Bug!  :-)

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.

 

I read up about the Wilson Benesh GMT One System turntable, which weighs almost half a ton and uses lots of materials science, university types and research grant money to minimise unwanted resonances. This behemoth does not have a cover, although it costs house-money! Obviouly they don’t worry about airborne feedback, or dust!

Can't trust reviews or media - the GMT has a very nice integrated hinged dust cover. Ideal for those who can't afford hepafiltration systems for their home/living room.

 

 

@billstevenson 

Since when are we taking anything Google's generative AI has to offer as an authority?  Frankly lewm's reference to the published work of Shure years ago is an established, credible resource and those who disparage it must be doing so only because they have not taken the time to read it. ...  After we get done talking dust covers to death, if anybody is left standing let's talk about the good old Dust Bug!  :-)

I did take the trouble to find and read thoroughly the Shure seminar articles.  Have you read them?  There is absolutely nothing about styli causing static except that throwaway line that it is negligible.  No experiment, no discussion, no measurement, nothing.

Generative AI uses large language models to make inferences.  Most likely Google's includes everything you have written on the web, and weighs it against what everybody else has written.  I find it both credible and fascinating.

My dust bug has gone missing, but the base is still stuck to my Garrard 301. I recall it quite audibly played what was coming up on the record, but have no idea why they fell out of favour.

@dover 

Thanks - I have asked Wilson Benesch for a copy of the 'white paper' mentioned in TAS's review, but it is not finished yet!