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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
drmuso's avatar
drmuso
114 posts
 

Having seen how dust accumulates on a de-staticized LP even with a dust cover on, I would never play a record with the dust cover off. I have a HEPA air filter in the room with the turntable, and I don’t think that completely eliminates accumulation of dust--I think it comes off clothing I wear and from the HVAC system if it is on while playing a record.

I suspect that any difference in sound quality would be negated (for me) by any additional tick noises that added dust would cause, possibly permanently. The three turntables I’ve used in the last 50 years all had dust covers that could be placed down while playing records. My turntable is a SOTA Star Sapphire, and I suspect the vacuum holddown reduces vinyl resonances so that the dust cover wouldn’t make much of an audible difference, but I’ll admit I haven’t even made the comparison. I will, just out of curiosity, with some record that I don’t care much about.

bigtwin's avatar
bigtwin
1,221 posts
 

For what it's worth, I have the Rega P8.  The dust cover supplied by Rega protects the unit while not in use, and is designed in such a way it can't possibly be used while the TT is in use.  I hope Rega knows more about this issue than I do, and will defer to their judgement.  

ltmandella's avatar
ltmandella
166 posts
 

Regarding ambient sound feedback:  I did an experiment one time in my listening room, with my RT-909 tape recorder and my Music Hall MMF-7 TT (project OEM tonearm).  The cartridge was a higher end GRADO.

I started the record playing, recording into the RT-909.  After the record play was about 1/2 way of the LP, I unplugged the TT BUT KEPT THE 909 TAPING.  So, the needle is sitting motionless in the groove of the motionless LP, with the RT-909 continuing to record the cartridge output.

They I walked around the room, clapping, shouting, humming, singing, and even stomping a couple times, all at various amplitudes.

You guessed it: when I played the tape from the "non playing" sections back, I heard many of the clappings, many of the shouting, some of the higher amplitude singing, and all of the stompings.

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

lewm
13,150 posts
 

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).

noromance's avatar
noromance
9,856 posts
 

I don’t use covers on my turntables. But I used to run a Linn LP12 decades ago. I did some experimenting with the lid up and the lid down. With a blindfold on and my partner gently raising and lowering the acrylic, I could hear the lid going up as a veil being lifted, literally freeing the music. Lid down, music became closed in. Same drill with covers on small signal tube amps. 

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