Repanelling ML Clarity's

[DouginDallas]

Is it possible to spray some sort of conductive coating through the stator onto the Mylar film to enhance the conductance if one panel is starting to sound quieter?

Can anyone confirm if this is possible? I don’t have the tools or the patience/skills/steadiness to take apart the panel but want to know if it’s possible to coat the Mylar through the stator.

 

[Stevieg335i]

Can anyone confirm if this is possible? I don’t have the tools or the patience/skills/steadiness to take apart the panel but want to know if it’s possible to coat the Mylar through the stator.

Hi,

I don’t think that this would work. Apart from anything else there is a strip of foil that supplies the HV to the Mylar /conductive coating and you can’t see it as it’s under one side of the stator. That would also need to be coated. Also you have to make sure that no conductive fluid is anywhere near the spars. I allow 5mm either side of each spar where there is no coating, otherwise arcing is very likely. You would not want the coating anywhere near the stators either as that would cause issues.

I just dont think you can do it this way. Splitting the stators and a rebuild from scratch is the only way I know to do it.

kind regards

steve

 

[Jazzman53]

Hi Jazzman, it looks that the Licron Crystal coating has lasted a little over a year and is now failing. I have to really bump up the preamp for the panels to sound just ok and still muffled. Visually the coating looks fine. Its happened to both speakers so I assume it cannot be the electronics and has to be the coating on the panels. If i rebuild the panels, this time I will use pre-coated mylar. It is available but not easy to source due to thickness and quantity. Else I've read that metallised mylar may also work though visually is not appealing. Hoping to hear some of your thoughts. I'll ask JonFo too about increasing the voltage. Maybe that would help.

I’ve only just seen this post or I would have responded sooner.

I’ve recommended Licron Crystal on my website for some years now, so I feel a certain responsibility when someone reports poor results with it, as well as a desire to figure out why.

Although I’ve used Licron Crystal for almost a decade on about 12 pairs of panels; I’ve given away my older ones and haven’t kept up with those. The oldest pair that I can personally attest to are 5 years old and their owner is happy with them. My personal pair of MkIII’s were completed in Jan. 2020 and I haven’t noticed any degradation in their output to date. Several of my audio buddies also have them (with my warranty) and have not reported any problems.

My friend Martin owns the MkIII prototypes (5 years old now) and their output measured 3-4 db lower than my newer/improved MkIII’s, when we compared them recently. We attributed the difference to the prototypes’ lower biasing voltage (2.7kV versus 3.3kV) and higher resistor values in the segmentation network (130kOhms per segment versus 107kOhms per segment x 8 segments). However; I can’t know for certain that all of the difference is due to aforementioned power supply components.

Several of my friends have speakers I built for them using Licron Crystal, and I’ve given them a lifetime warranty on the panels (my lifetime, not theirs), so it’s concerning to read here that others are reporting problems with the longevity of the Licron Crystal.

I’ve read conflicting reviews on the Staticide coating as well, some have reported very good results with it. The manufacturers (Staticide and Techron) advertise them as permanent coatings but then again, I doubt they tested them using the kind of continuous charge applied by an ESL bias supply.

I’m also wondering if variables in the application method, environment, playing hours, etc… could affect the coating longevity. In this regard; I can only say that I always apply the coating inside my air conditioned house rather than out in the garage due to concerns about humidity. Also; I spray on a single “just wet” coat. I also use a full-periphery copper foil charge ring for the bias supply connection, rather than a local-contact connection.

At this time; I’m at a loss to explain the reported different results with Licron Crystal.

 

[Jazzman53]

I've used Licron Crystal for some years with no problems so far, but after reading other builders' reports of it failing over time, my confidence in its longevity has waned, and I'm now looking at other coating options.

I'm not planning any new speaker builds but if the Licron coating fails in my speakers or any of the six pairs I've built for friends, I will replace the diaphragms and coat them with Statclear A50.

I have no clue about Statclear A50's longevity and I doubt anyone else has used it long enough to confirm that either. I've read one post in this thread where Statclear A50 was used and the speaker failed very quickly, but in this case I believe the failure was likely caused by a conduction path which shorted the panel. Other reports for the Statclear A50 have been positive and the manufacturer states that they have supplied it to four ESL manufacturers, so I think it's worth trying. Here's a link:

https://electroguardpaint.com/statclear-and-esl-audio-speakers/

 

[Rob606]

Hi Rob,

Get yourself a 1 gigaohm resistor and you can measure through that with a normal meter.

Undo the connections from the main board to the HV step up transformer. Put the resistor in Series with one side of the HV output and the positive side of the meter, then connect the other side of the meter to the other HV output. Set your meter to dc voltage and up to 200v. Then you are all set.

I’ve used my SL3 main board as an example as I had it handy.

View attachment 22457

So you can see in my case the HV supply is 2180 volts. (21.8 x 100)

Just note that unless you supply a signal to the speaker terminals the power supply doesn’t stay up for very long, in my case around 30 seconds. But it’s enough to take a reading

HTH

Kind regards

Steve

Hello again Steve. I know it’s been some time since you posted this and I never saw this message. Don’t think I get notifications about thread posts. Nonetheless I wanted to say thank you for your outstanding help!
Kind regards
Robert