2. analog
  3. 192567-1647

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
mylogic
35 posts
 

I believe the previous post is hi-jacking this debate.

I thought we were talking about turntables cover on or off?

 

Anyway, back on track please…..

 

oldaudiophile, you are a kindred spirit. I believe entirely what you say. I replied to the original poster without reading all through the other replies. I did not ‘hack’ your opinions but we are of the same old school l believe. Yes Thorens did a public relations job on that complaint about the cover being too small and unfit for purpose.

 

l am in the UK and Thorens dominated mainland Europe in the 70s and 80s (not UK which was Garrard territory). I am very familiar with Thorens turntable owners in that period and spent many evenings music listening with their set ups. I can never recall any manuals stating remove the covers ever! Unless someone bought a chassis deck to install on a hi-fi bench then the cover on or off issue may have been different.

Hi-fi has become a bit of a home living statement now so it must be always on show. Now it’s all about design over aesthetics and manufacturers today have abandoned in most cases the use of turntable covers.

 

 

 

 

 

 

 

 

dwette
186 posts
 

@elliottbnewcombjr 

I use a center weight and peripheral ring on my Clearaudio Innovation and they work quite well. However, the turntable is designed for them I also use Clearaudio's versions so they fit and do the job perfectly.

mylogic
35 posts
 

Elliot your bias compensator is way off….

This thread is about turntable covers … on or off!

richardbrand's avatar
richardbrand
240 posts
 

As a record rotates, the air closest to the surface gets accelerated towards the periphery, drawing a steady stream of air down around the spindle. So reduction of air-born dust suggests closing the dust cover during play.

A dust cover also acts a bit like closing a window, and it will attenuate external airborne vibrations from reaching the cartridge.  My Garrard 301 table is in the same room as my speakers, which are either dipole Quad electrostatics or KEF Reference 1 with rear ports.  The dustcover is an acrylic affair made by SME and is voluminous with plenty of space.  I am very surprised that the sonic effect of closing my dustcover seems to be subtle to non-existent, at least to my ears.

Obviously, there is acoustic output from the needle / cantilever which is partly airborne and partly transmitted through the vinyl record, I am using a 5-mm Achromat to absorb record reflections and transmission to the platter, which leaves those airborne sounds we can just hear if we are close enough. They will reflect internally from a lowered dustcover but I would have thought the sound level would be far less than the speakers generate with the lid open!

So I put the lid down unless i forget!

lewm
13,208 posts
 

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.

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