Can Externally Applied Static Damage MLs?

[Victor]

Reason I ask this question is that I was about to cover my Vantages before decorating the house. In order to protect my speakers from dust I procured some king sized clear plastic bags to cover the stators with...

Then it suddenly occurred to me that the plastic bags when opened contain a massive static charge? If these are applied directly to the Stator when the Stats are disconnected from the Mains, can the High Voltage Power Supply be damaged ???

The other question is, can the external static source leech away any of the conductive coating or damage the membrane by discharge?

Feedback much appreciated.

Victor.

 

[lhpcope]

I use the big 55 gal bags regularly to cover my MLs. Yes they do have some static associated with them when new but no issue yet

 

[Victor]

Thanks LHP...

Given that the Electronics industry is paranoid about Static contact with SS devices such that manufacturing staff are forced to wear earthed bracelets when handling semiconductors it makes you think about the opportunities for casual discharge onto your MLs (synthetic clothes, carpets discharging using you as a path etc.) The possibility of a Stator suddenly going from 0 to 30kV and back to zero again made me wonder...

The fact that the Stators are connected to a transformer doesn't inspire confidence either as there is sure to be a direct link into the electronics?
This could be scaremongering but interesting to know what the Forum thinks?

Victor.

 

[JonFo]

Hi, I would not think there is much risk of Static discharges hurting the stators or the Diaphragms, as they normally withstand up to 5,000 volts.

The step up transformer is pretty solid, so that’s not too big a concern.

ML models with built-in active electronics (powered woofers etc.) *might* be more susceptible, but hard to say. Those electronics are pretty isolated from the panels due to the high-voltages normally associated with them anyway.

The other question is, can the external static source leech away any of the conductive coating or damage the membrane by discharge?

Huh, nope, not that I can think of. That conductive metallic coating is vapor deposited on the Mylar and is bonded pretty well. Unlike old rubbed graphite approaches (or hobbyist solutions), the materials used by ML in the last decade are quite durable.

My recommendation would be to just put the bags on and take them off slowly to minimize static build-up and discharges.

 

[OldMonolith]

I would expect the risk to be to the bias supply diodes. I don't think that a pulse on the panel would be likely to get too much of that energy to the PS though due to the extremely short nature of it. Guessing though...

PS do have issues sometimes, but they are hooked to the power line a lot of hours!!

OldMonolith

 

[Victor]

Hi Jonathan/OldMonolith,
Good answers guys....
Certainly I don't remember seeing any warning messages in the ML FAQs about this effect (and to be honest, ML deliver them in plastic bags - usually with the speaker's veneer protected by a soft paper cover)

It looks like the best advice, as a precautionary measure, is simply not to use polythene or retain the original paper covers ?

Victor. :music:

 

[Victor]

...Oh...and don't touch 'em when you're wearing clothes...

 

[lhpcope]

Does anyone have a schematic diagram that could be analyzed for this sort of thing? And while the new bags do stick to my stators I have never seen or heard a discharge.

 

[Victor]

Which MLs do you use by the way LHP ? Active or Passive ?

 

[danman]

Don't most models have stand by tramsformers? If there is no current when removing the bags I would think there would be no problem.

 

[urskog]

Seems to be a lot of uncertainty and doubt here so I would say the best course of action would be to email someone at ML directly and ask, if anyone knows it should be them.
My gut feeling as an engineer says that it probably isn't a big risk involved but its better to ask the people in the know

 

[lhpcope]

Which MLs do you use by the way LHP ? Active or Passive ?

I have Prodigies. No on board amps here.