That’s what she said.
57 responses Add your response
@lewm , the sub chassis, a 1" thick aluminum plate is hanging from 4 dampened springs that are attached to the underside of the plinth (Sota calls it the cover) top surface. The Three adjustable feet are threaded to posts that travel through holes in the sub chassis and also attach to the underside of the plinth upper surface. Nothing touches the sub chassis but the four springs, the main bearing and the tonearm board. The duct cover is hinged to the back surface of the plinth (cover). As supplied by Sota there were two rubber pads on the front upper surface of the plinth that the dust cover rested on. I did not like this arrangement as it left an open slot of about 1/16th inch all the way around the turntable. Fortunately, the dust cover hinges are adjustable. I removed the rubber pads and applied 1/4" wide, 1/16" thick heavy felt strips all the way around turntable and adjusted the hinges so that the dust cover sits flat on the felt completely closing off the upper chamber of the turntable. The sub chassis is further isolated from sound by the skirt that I made which closes off the bottom chamber of the table. There just happen to be two pictures of the table on my system page. The picture without the maple skirt shows the table as supplied by Sota with the two rubber pads at the front corners. The picture with the temporary maple skirt show the table with the felt gasket on the sides. The felt is brown so you have to look closely to see it. I had yet to install tthe felt along the front and back. When I get a chance I'll take a picture of the table as it is now. I'll also run another sine sweep with the microphone under the dust cover to see how much quieter it is. I just have to figure out how to get the mic's cable in there without breaking the seal. I'm hoping to get another 5 dB of attenuation, maybe more? Whatever, the turntable sounds great. |
There doesn't seem to be much concern about the dust itself-- which is bad for your turntable-- it gets everywhere-- and bad for your records. It gets in the grooves, creates ticks and pops that are not always easily removed with cleanings. Some turntables should be used with the cover completely removed while others, like a SOTA Star Sapphire are designed to work with the cover on and closed. So like most things audio-- it just depends. The least good thing to do is leave the cover on and up during playback. I use a fine quality paintbrush to dust off the platter between plays, and the plinth every few days. Dust accumulation is bad for your gear. |
Mijo, I am trying to understand the structure of your Cosmos. Am I correct in thinking the cover hinges to the rear of the wood that forms the visible outer appearance of the TT? And you’re saying that the wood plus dust cover are isolated from the works by the spring suspension? If I’ve got it right, doesn’t the peripheral edge of the lucite also contact the wood, on at least 3 of 4 sides? Or is there a spacer that keeps them apart? |
A proper dust cover is a big plus for a turntable both sonically and for protection for records and tonearms. What is a proper dust cover? @herbreichert has notice no problem with his Linn. @fbgbill I do not know if you think a Sota Cosmos is a high end turntable but it does have a dust cover and like Herb's Linn the Sota's dustcover is isolated from the turntable, tonearm and cartridge which are floating on a separate sub chassis. That is the most important criteria for a proper dust cover. It can not directly transfer vibrations to the working parts of the turntable. Used like this a dust cover actually improves the sound by attenuating the sound that gets to the cartridge like wearing ear muffs. In a system with Electrostatic speakers the improvement in detail is noticeable. This leaves a lot of turntables out in the weather but, there is a solution that can be used with any turntable. You have a baseplate made that is larger than the plan view of the turntable to which you can hinge the dust cover. The baseplate could be made out of wood, acrylic or even granite. There are plenty of companies that can make a dust cover of any size. You place the turntable on the base and the dust cover closes over it. I'm surprise there is not a company that makes the whole rig. I am not the only one who thinks this way about dust cover. In an email conversation with Mark Dohmann he related that he was working on such a dust cover for his Helix turntables. @jagjag , unless you live in an industrial clean room there is no such thing as a dust free environment. Another issue is there is no such thing as a static free record. There is always a slight charge on records. Even if you ground out the record with a dead short within a short period of time the record will develop a charge. Why? The paper label and PVC are at opposite ends of the triboelectric series. Electrons migrate from the paper label to the vinyl giving the paper a slight positive charge and the record a slight negative charge, more than enough to collect dust. During play the record also develops a little more of a charge. |
soko, I don't agree with your interpretation. There was a time in the history of audio per se as a hobby, let's say since the mid-60s, when the dust cover was an expected part of a turntable, and many manufacturers provided a hinged attachment for convenience. I never took that as an indication that the manufacturer was recommending anything. It was just a feature that might seduce a buyer. In many cases, where there is a hinged DC, the hinges are designed such that the cover can be totally disengaged from them to allow for their complete removal. I wouldn't over-interpret that, either. |
If the manufacturer provides a hinged dust cover, they must be saying down when playing. A non-hinged one or one like my Rega P8 is saying off when playing but on when not to keep dust off. Some like the big ones over everything not hinged to be on while playing that don't touch the plinth or base which might be better at eliminating air borne vibrations and accumulating dust while playing, but what a pain moving them on and off when flipping a record - double worse for 45s. Unfortunately in our hobby there is no perfect solution....to anything. Just keep trying to get as close as possible. |
I’ve got a digital VTF scale, and I do have the dust cover from my Victor QL10. It sits on the floor under a table near the QL10, but for me there are other more major reasons why I don’t use dust covers so I won’t be participating. Moreover, it is clear to me that you would have to do something with the dust cover in order to build up a charge on its inner surface. I am not sure what that is, short of rubbing it with a cloth or something of that sort. Anyway, I could not care less. On the other hand I believe those who report a difference. I don’t know how you interpret those posts, but obviously we disagree on how to interpret them. If you would prefer to think the score is nil, then it is nil divided by nil, and we all know what that is. |
I've just re-read the thread and as I thought, no-one said they had measured a difference in VTF. Two said there might be a difference. So far then the score is nil posters have measured any difference. We've all got those digital scales, so why not get down to it - a minute or two's effort. I would certainly try, but I don't have a dust cover. The subject is interesting because this is one pretty stupid tweak where a scientific measurement can easily be made, and proven by weighing with cover off and then doing it again to test the scale is true. I'm putting my money on 'no difference'. |
| Post removed |
HI As with most things in life the answer is……it depends! I have a VPI HW 40 with a dust cover and it works and sounds the same with the cover up or off. If you want that extra bit of assurance that the dust cover won’t negatively impact the sound, you could attach a piece of bubble wrap on the underside of the cover and away you go. My VPI HW 40 is used with a Kisiki Purpleheart and Sutherland phone stage. Cheers Jerry |
It is true the cover may transmit air-borne vibrations to the stylus/disc interface. But it may also be true that it shields that interface from those vibrations by acting as a a barrier whose micro flexures absorb them. Anyhow my TT has no cover so I can't hear it. Plus it doesn't seem to become inordinately dirty. I think many audiophiles over-analyse. That is ANAL ise.
And hands up please anybody who has observed any tracking weight variation at all with lid up or down using an electronic scale that measures to 0.01 gramme?? So let's kill that one right off. |
I think with a fully suspended table like a Linn LP12 the dustcover is less likely to color the sound, but with a non-decoupled plinth it’s much better without the cover or at least with cover up. I have seen the static attraction effect at work myself so that’s another reason to go up or off. My WTT/TA has an unhinged “cake cover” so it gets removed for playing every time. I once had a Technics SP12 with a heavy rubber plinth and the dustcover really degraded its sound quality when down. |
My rega RP8 has a surround support and dust cover... After 3 years I removed everything bar the Skeleton inner. Sounds much better... So was looking for large perspex cover for dust protection when not used... But just ordered a michell uni which is sleek and minimal Will work for a lot of smaller decks like Kumzi rega michell
|
I have a Sota Comet I bought used and the dust cover is more or less an afterthought, and looks like it, something they started making because there was a demand for it. There are holes for hinges in the back of the plinth, but it's clearly never had hinges on it. I take the cover off and set it aside while playing records. |
Don’t have, and don’t use a dust cover. Will likely get one made for my TT to keep the dust off when not in use, but seeing as how it is used daily, it will be spending the bulk of its time stored near by. Suspect if I get one made, it will be used if I go away for an extended time.
A friend of mine leaves his on all the time, which is easy as it is hinged. Opens it, puts a record on, closes it. Seems to me, as the price of a TT goes up, the presence of a cover becomes a rare thing indeed. Especially one that is hinged. Can’t think of a single ultra high end TT that has a hinged cover? Would love to know if there are any? |
People spend tons of money to reduce any adverse effects on their turntable caused by vibrations. Removing the dust cover while playing a record is probably the cheapest way to reduce microphonic vibrations that will cause distortion in sound. Some cheap turntables with cheap cartridges may not make much difference with or without a dustcover because the sound is already pretty bad, but very revealing high quality cartridges may suffer from such vibration especially when you listen to music loud with the dustcover up. The dust cover will pick up the sound wave, however small, which may well cause vibration. |
Fascinating. I would not have thought the attraction would be so strong over what would typically be the ~6-inch distance or so, between cartridge and dust cover. So ES on an LP can spuriously increase VTF and ES on the dust cover can lower it. If you're lucky, the two attractions are equal and there is no change in VTF. So one other solution is to rub up your LPs with a wool cloth before play with the cover down. |
Cleeds, now that is a new one to me (dust cover reduces VTF by electrostatic attraction). How did you figure that out, given that you can’t measure VTF with the cover down? Or I guess you could, by raising and lowering the cover with the scale in place that you could read through the transparent cover. |
