Some thoughts on dust covers

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.

I have a Rega P6 with a dust cover. I have always used it with the cover up for no particular reason. Convenience maybe. Reading these posts I went up to do an experiment to see if I hear a difference. I was gonna try cover up, cover down and cover off the plinth with my best quality records. I dropped the needle and NO LEFT CHANNEL! Turns out the amp picked that day to crap out. It's under warranty so I'm sending it off to Focal Naim for repair. I'm still gonna do the experiment but it's going to be awhile. I doubt my set up is detailed enough to hear a difference.

@lewm

"Dover [actually richardbrand] 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."

So you did not really trust the Shure ’white paper’ you quoted to support your erroneous assertion! That’s quite an admission from somebody who claims to want the information on this site to be as accurate as possible. According to your posts, you had a residual voltage of 100-Volts after Zerostat and 200-Volts after playing, but you have not stated what meter you used or its repeatability.

This is what the Shure seminar actually published on methods to reduce static. My highlighting and [comment]

There are four systems available:

1. Sparking

2. Ionization

a. Active - ac powered, hand powered, radioactive

b. Passive

c. Contact

3. Conduction

Sparking is an automatic mechanism which, as we have seen, limits the free air voltage to about 30,000V and the threshold voltage of a pickup to 4,200V. However, the residual voltage is still high enough to cause all the observed problems and the effect is only included in the list for the sake of completeness.

Ionization, or the production of charge-carrying atomic particles, is a particularly effective way of neutralizing charges. A system similar to the arrangement used to charge records is commercially available for destaticizing photographic film. This system uses an array of multiple points covering both sides of the record simultaneously. Its operation floods the record with positive and negative ions alternately and "washes out” any initial charge on the record. This system is the most effective of any available, but it is expensive and the high voltage construction and safety requirements make it difficult for the home constructor to duplicate.

Another form of active ionizer is in the form of a pistol-shaped, device, which produces positive ions when the trigger is pulled, and negative ions when the trigger is released. This device is effective for large charges, but it is hard to avoid leaving residual charges on the record since there is no way of detecting the zero charge condition.

The third form of active destaticizer uses radioactivity to produce positive ions. This type of device is limited by safety restrictions to a rather low level of ionization and, hence, will deal with mild charges but requires a long time to affect strong charges.

The passive types of destaticizer have used bundles of wire and tinsel, passing over the surface of the record. These devices promote ionization because of the voltage gradient which a charge induces in the vicinity of a point. This arrangement is self regulating, since the ionization is proportional to the charge which produces it. However, in its usual form, the effectiveness is limited by the sharpness of the points available.

This limitation can be greatly diminished by using carbon or graphite fibers which have a diameter of .3 mil, and which must have an effective radius at the cut-off end much smaller than that. A destaticizer using these fibers will be considerably effective even if the fibers do not touch the surface. The difference between a contact mode and an ionization mode is hard to distinguish, but we regard actual contact as the distinction. Since charges have no nobility [I think the author meant mobility], it is necessary to touch each and every point on the surface to discharge it. Here again, the carbon or graphite filament is superior to other types. A wipe with a grounded carbon filament brush can reduce the charge on a record to negligible proportions

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.

"About 1,000,000,000,000,000,000,000,000,000,000,000,000 times different! "

This just in!

For the curious tuning in, that ludicrously large number is One Undecillion.

And now back to our regularly scheduled program: ’Battling Eggheads... '