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Old 21st June 2011, 10:04 AM   #1
tyu is offline tyu  United States
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Join Date: Jul 2009
Default A MUST DO To All ESL

Mr West Has It

The actuating force in an electrostatic speaker is created by the interaction of a constant (unchanging) charge placed on the membrane (by the bias power supply) and the signal charge placed on the stators (by the audio amplifier). The membrane is specially treated so that its surface is electrically conductive to enable it to accept an electrical charge.
Ideally, the charge on the membrane should be perfectly uniform over the entire surface of the membrane. If any electrical leakage paths exist that bleed charge off of the membrane the charge density in that particular region is lessened and sound production is reduced in that area. This results in a lower overall speaker sensitivity. Leakage paths normally occur around the outer edge of the membrane where it is attached to the panel frame. These paths are usually caused by condensation of moist air in humid climates. They can also be caused by air-borne contaminants that are attracted to the membrane such as an accumulation of microscopic droplets of cooking oil, carbonaceous particles in cigarette smoke, normal room dust, etc.
The pure-copper charge-diffusion ring effectively blocks electrical leakage paths and therefore maintains a uniform charge density over the surface of the membrane. The pure- copper charge-diffusion ring consists of a copper foil strip that is placed around the periphery of the conductive membrane. The bias voltage supply is connected to this strip. Charge is diffused from this ring over the conductive surface of the membrane. If moisture or a contaminant forms a potential leakage path from the membrane to the panel frame it must cross the charge diffusion ring. The charge availability of the ring is engineered to be capable of supplying charge to any leakage paths that might occur while maintaining the proper charge density on the membrane. In this way, leakage paths may occur but they donít affect the charge on the membrane and sound is not affected.
A simplistic model may help to understand this principle. Consider a bathtub as an analogy. In this model, the depth of water in the tub represents the charge density and the faucet represents the source of charge. If the tub has a leak, the level of the water near the leak drops as water is drained from the region (if a substance other than water was used such as molasses or sand the action would be easier to envision because of the slower flow). Now, instead of using a localized source of water to fill the tub, as represented by a faucet, consider using a conduit that forms a complete ring around the sides of the tub such that it feeds water into the tub at all points around its boundary. It is assumed that the amount of water that the ring can supply is adequate to feed the leak while keeping the level in the tub at the desired level. The net result is that the water in the tub is undisturbed by the leak. The action of the charge diffusion ring is directly analogous to this in a two-dimensional sense.
The pure-copper charge-diffusion ring eliminates the effects of dust and other common environmental contaminants. The "ring" is crucial in hot, salty and humid climates.

This Give FULL output of any ESL there is no other way.

You can get the panel to work but not at full output.If Like ML you Feed the Bias on one side Then When Just A small bit of Dust or even a hair can pull down the Bias

Now as for The pure- copper good but not the only way,i say doing this has gave 3-4dbl more output ever time an thats a big DEAL with ESLs
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Old 21st June 2011, 03:01 PM   #2
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Location: Netherlands
This charge ring is as old, or older, than the Quad ESL which already had one in 1955. So a nice sales pitch by Mr West but nothing new really.

And of course it does not remove all leakage paths. A hair in the panel can still drain the charge.
my Quad ESL website.
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Old 21st June 2011, 03:06 PM   #3
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Join Date: Feb 2008
Location: Jackson,michigan
I have not seen any difference in performance in my panels whether or not I have incorperated a charge ring.

However I am not stating that one should not uses one.

Infact on one panel it only created havoc after one was added ,But only because in the original design there was not enough room to have one and caused an arc over near a mounting bolt.
That was a flaw that will be corrected on the next build.

The only time that I found a charge ring nessesary is when a crack formed in the diagphram coating around the perimeter of the frame and stoped the diagphram from charging,But that was a coating issue and since has been solved.

There has also been issues with using copper as the material for the charge ring,in a very high humidity enviroment as they have a tendency to corrode,Therefore I have incorperated a graphite based charge ring and this works very well,much cheaper than using a gold coating.

And there are other ways to seal it so that moisture does not seep in causing corrosion of the ring.

There is no protection against leakage as if there is a path for the charge to leak through it will.
Much care and cleanliness must be taken in this area during construction so that know contaminents will be introduced to cause a path for leakage.

The charge ring does not protect the panel from any dust or contaminents only dust covers do.

I have deliberatly soiled and abused my panels for seven years to check the durablity of the coating that I used when I built them in 2003 and when I fired them up for the first time last year (2010) they worked just as the did as when they were first made and no charge ring was incorperated in the design.

The only thing was there was a little loss in detail cause from the extra weight of salt and sand stuck to the diagphram.

This was completely documented in the coatings thread along with the appilication of the graphite charge ring that I had developed.

The charge ring was the very last modification and made no difference in performance of my panel compared to the other identical panel that does not have a charge ring.

Normaly any leakage that occurs is from an inferior stator coating,This I have found out as I have two identical sets of panels with different stator coatings.
One the can withhold 8kv or more of bias voltage and one that can only withstand 3kv-4kv of bais voltage and this is where a big difference in performance is.

However I like your anology of the function of the charge ring.
But if one does not incorperate one it does not mean that the panel won't work or even too it's fullest potenial.
If it doesn't then there are other issues that need to be adressed.

Just my IMHO. jer
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Old 21st June 2011, 03:49 PM   #4
tyu is offline tyu  United States
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Join Date: Jul 2009
Default Old Panels

I have had ML ESL An other ESL for 30years,ML Panels get weeker as time pases,i got Mr Powers at ML to send me NEW panels an found Thay were no better than what i had,the panels that i had were only 5 years old
An i new that thay should not drop in output, so looking in to it i found thay only put the bias feed on the right, Just by going in on the other side with a Bias feed,did not just turn the panel on,but the never sounded so good,i can drive the with a 60w tube amp, Now i have done 3pr of ML panels an all have gave at lest 3dbl more output, some of the panels were 15 years old

The Ring i used is alum duck tape,works good,i cut into strips

Thanks for all the info you can give

Just one mans O-Pine
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Old 21st June 2011, 04:33 PM   #5
diyAudio Member
Join Date: Feb 2008
Location: Jackson,michigan
I have used aluminium tape in all of my builds for conections it works well.
Except you can't solder to it so a good mechanical connection is all that is required.
It sound sounds like there may be some kind of coating consistancy issue that you are having.

As I have mentioned I have had cracking in the coating around the perimeter of the frames causing an open circuit not allowing the diagphram to charge at all.

I find this to be very strange coming from a commercial manufacture.

I first started with graphite as a coating and had several problems with it.

Then I switched to licron spray (original formula),this stuff worked great However it proved to be bit brittle and it would flake of off the mylar under stress if it was not absolutely clean of any oils from touching it when it is applied.

And it was when I had the cracking issues only around the primeter at the flex point.
So to remedy this I would just make the coating a little thicker around the perimeter and never had a problem after that.

Then I discoverd the new formula Licron Crystal (last year) and it seems to be the perfect coating.
I have not had one issue with this coating.

I don't know what ML uses or their process has they all claim to be properietory which is understandable.

But if you are having an increase in effeciency buy adding a second charge connection then this is something that should be mentioned to ML and they need to re-address their methods of construction.

One thing about using aluminium for connections , is, it does (and always will) form a layer of oxide on the surface and can be insulative,and hav had a failure in a connection because of it.
But this is not too much of an issue although I have experienced this,Just scuff it up with some steel wool before assembly,

I hope that helps. jer

Last edited by geraldfryjr; 21st June 2011 at 04:40 PM. Reason: forgot stuff
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Old 21st June 2011, 05:18 PM   #6
tyu is offline tyu  United States
diyAudio Member
Join Date: Jul 2009
You say

But if you are having an increase in effeciency buy adding a second charge connection then this is something that should be mentioned to ML and they need to re-address their methods of construction.

I been told Most buy the ML for looks,
Let me say ML dose not wont to talk about it THay Make BIG money saleing New panels ,An a good man ML Jim Powers is Dead, sucks but i well be soon too that life

But have got some trick from Mr Powers Like The Tranfourmer Set up thay used,to get more output out of the panels It works Well even on Fullrang ESLs,It not Puspull

thanks For your time

I miss my Bud Moray james

I have been told That ML Panels Just HAD to be Clear,that was more inpoartin for Panels
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Old 21st June 2011, 05:27 PM   #7
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Join Date: Feb 2008
Location: Jackson,michigan
Yes ,I agree it is unfortunate the loss of super people in a company whom is willing to listen to the customer to improve their product.

I have had many a long interesting conversations with Moray James It would be cool for him to chime in here.

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Old 21st June 2011, 06:26 PM   #8
diyAudio Member
Join Date: Aug 2003
Location: Calgary on the Bow
Sorry guys have not been avoiding just have a very full plate right now. Have not been active with the stats for a whil but have plans and parts so not going away. Have been having fun with Klipsch and horns are a great way to get dynamics as are ribbons and ESL's. Regarding the charging ring I think it would be a lot easier to simply use wire to make charge contact points at intervals so that you have an average distance. That way you don't have to rely on charge migration over a long distance to keep the diaphragm static charge even. I have used the Lycron and while it costs a bit it works very well. I have some auto detailing products which actually bond on a molecular level to polyester and plan to see if they work as well as the Lycron.
Wish I could come to FLA for a visit and a BUD with my buddy. I chime in here when I figure I might have something of use to add. You guys are doing a great job. Best regards Moray James.
moray james
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Old 21st June 2011, 06:35 PM   #9
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Location: Jackson,michigan
Thanks,Moray James!
I too have several projects going on and it seems like they will never get done sometimes.
But they will eventualy.

Good luck and keep on DIYing! jer

Last edited by geraldfryjr; 21st June 2011 at 06:47 PM.
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Old 24th June 2011, 02:32 AM   #10
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Location: Fort Worth, Texas
Originally Posted by tyu View Post
But if you are having an increase in effeciency buy adding a second charge connection then this is something that should be mentioned to ML and they need to re-address their methods of construction.
Perhaps this quote from a ML factory tour might have something to do with the charging problems you describe. Evidently they coat the diaphragm before stretching it. They most stretch it a LOT top to bottom because:

"Step 4: After being wiped down to remove any oil, dust or foreign particles, a conductive graphite slurry is wiped across the entire panel to fill micro-fractures which occur naturally during the stretching process."

Here is a link to the blog posting:
Making of a MartinLogan Electrostatic Speaker Panel | Caster Communications

In case it eventually disappears, attached is a screen capture.
Attached Images
File Type: gif SLURRY.GIF (58.4 KB, 424 views)
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