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Back To Static!

We had a long discussion on the possible causes of static electrical charges on records in another thread. We just had a real good cold snap in New England dropping the humidity to under 20% so I was able to run a set of qualitative experiments documenting some surprising results that I hope will clear up a lot of the mystery and help people contro static charge and the accumulation of dust on their record. 
Static field meters are expensive.  The cheapest one I could find cost $260. I had to find a more sensitive way to measure static as it became apparent that using your own hair is very insensitive. Studying the Triboelectric series I noted that polypropylene is at the opposite end to PVS.  I have polypropylene in the form of suture material, the blue thread that many of you have seen. I tied a length of 6-0 Prolene  to a wood dowel and it worked beautifully. The PVC attracts it like a magnet and the Label repels it. It will pick up very small charges that otherwise go undetected. I can now define four conditions; No charge, Light charge, Charged and Heavily charged. It turns out that completely discharging a record is not easy. The label will actually donate electrons to the vinyl over time reaching an equilibrium point. Totally discharging a record required using a Pro-Ject conductive record brush wired to ground. If I suspend a discharged record (no thread activity) by it's hole within 30 minutes it will develop a slight charge (vinyl attracts the thread, label repels it). This will appear to us as an uncharged record. 
Does playing a record increase the static charge?  Yes absolutely, and the charge is additive. Playing the record over and over again progressively increases the charge from slightly to heavily charged. 
Does how you store the record effect charge? Yes absolutely. Records stored in MoFi antistatic sleeves come out with the baseline small charge. Records stored in paper come out with a noticeably higher charge. These are records that have been totally discharged prior to storage. A record that is charged when you put it away will come out at least as charged even if you are using anti static sleeves. Do conductive sweep arms work? Sort of. If the sweep arm leads the stylus charge will still accumulate. The brush has to track with the stylus. 
Unfortunately, I could not get hold of a Zerostat to test it's effectiveness. Regardless, a charge will accumulate with play.
The single best way to totally discharge a record is a conductive brush wired to ground. Just holding it will not work as well. The impedance of your tissue is in the megaohms. You want a dead short. Even so, a small charge will accumulate over a short period of time. The safest assumption is that there is always a charge on the record attracting dust. So, don't leave records out for any period of time. In regards to the hot topic of dust covers, a properly designed Dust cover does not affect sound quality. If your dust cover does effect sound quality in a negative way then you have a choice between sound quality and dirtier records. Your records, your choice. 
I would love to be able to stage voltages. If in the future I manage to come up with a static field meter I will repeat all of this in a quantitative way. Humidity is a huge factor. Those living in more humid environments have less trouble with static accumulation. I suspect everything occurs in like fashion just the voltages are lower. Lower to the point that they do not need any device to lower the charge?  I don't know. 

128x128mijostyn
mijostyn's avatar
mijostyn OP
8,570 posts
 
I hate to be a PITA but this is heading off topic. Mats will never entirely discharge a record as the side that was played last will always have a charge unless you purposely discharge it. Electrons do not like turning sharp corners. I do believe that the charge will equilibrate over both sides eventually. I should try and test for that but it will probably require a more sensitive measuring device.
It is important I think to avoid the worse case scenario which is records stored in paper sleeves and played repeatedly on an improperly grounded turntable in low humidity conditions. The single best way to discharge a record which should be done before and after play is with a conductive brush wired to ground. For this project I used a Pro-Ject brush
drilled a small hole in the metal casing and attached a 24 gauge wire with a sheet metal screw. This is a very simple project (again) and requires only a drill and bit. Another approach is to use a conductive sweep arm wired to ground which is just a miniature version of the above.
slaw's avatar
slaw
22,042 posts
 
Thanks for you compliment @antinn ,

I’d hope members would look through all my posts to see I’ve been a (try for myself before posting) person.

Your mat postings weren’t reviewed, however, because of your history, you are taken more seriously than I am. I understand this, yet in the end, it all comes down to the end users’ sound. This is where we all meet, and this is ultimately the most important thing.

Look forward to another member here posting thoughts on the MyMat system very soon.

Steve
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lewm
13,296 posts
 
Mijo, what happens with the label-less LP?
mijostyn's avatar
mijostyn OP
8,570 posts
 
@lewm , I have not had the chance to deal with it. I am in the process of building  a bar and built in cabinet and am up to my eyeballs in sawdust not to mention I have no turntable at the moment. I will get around to it.
antinn
408 posts
 
@mijostyn,

In my travels I can across this paper - Microsoft Word - SEALEZE_WHITE_PAPER_Final dam.doc.  My takeaway is that even under ideal application & use (i.e proper grounding) brushes are not that effective in removing static.  

Recalling the article - Phonograph Reproduction 1978, James H. Kogen, Audio Magazine May 1978 ( Audio-1978-05.pdf (worldradiohistory.com) that goes into some detail on static; what causes it and what does not (the needle in the groove was not a source of static). The article indicates that static is not uniform, but exists as islands on a record. Additionally, once the static gets high enough to discharge to the cartridge it only reduces to about 4200 volts. A static charge on the record of 4200 volts will not create noise by itself, but it can by electrostatic attractive forces cause a transient increase in cartridge VTF as much as 0.375 grams leading to distortion and premature wear.

The implication is that a grounded brush can reduce static from a record to below audible (static discharge noise) but not low enough to eliminate the secondary effect of increasing VTF.
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