Panel cleaning question

[MickyP]

If I look at my SL3s panels with a magnifying glass I see a brown-ish spot in the centre of each perforation. If I (gently) rotate a cotton bud on the membrane, this is easily removed and the end of the cotton bud is quite blackened. Just wondered if there was any sonic value in 'dry cleaning' all of the perforations. Has anyone done this?

Thanks

 

[ttocs]

Airborne particulates that have accumulated on the mylar are most likely also accumulating on the stators as well. I believe an audible benefit would be gained by cleaning some parts, the mylar, and more benefit by cleaning all parts including the stators facing the mylar. The audible amount of degradation that can be heard is probably difficult to predict, but it may only be similar to using a tone knob on an old preamp.

Over what period of time has this accumulation occurred?

 

[MickyP]

Thanks for reply.

The speakers are 20 years old, but only been in my care for four months or so. I don't know if they've been repanelled at some time. Are they all like this (the brownish spot)? Maybe one owner was a smoker. :-(

 

[TomDac]

Might be time for a shower.

http://www.martinloganowners.com/forum/showthread.php?12584-Martin-Logan-Shower-Cleaning-PDF

 

[MickyP]

Might be time for a shower.

http://www.martinloganowners.com/forum/showthread.php?12584-Martin-Logan-Shower-Cleaning-PDF

Ha! Thank you. Still a bit nervous tbh.

 

[TomDac]

Yeah.. I've never done the shower thing, but it seems like it's effective.

 

[Tosh]

What you've discovered is a graphite coating which starts to migrate and concentrate under the stator holes and make a spotty pattern. It's not dirt, and it's normal.

 

[ttocs]

What you've discovered is a graphite coating which starts to migrate and concentrate under the stator holes and make a spotty pattern. It's not dirt, and it's normal.

You just blinded me with science! This is interesting. Is there a predictable amount of time after which this phenomenon occurs?

 

[MickyP]

Have pinged the factory and will pass on what they pass on.

 

[MickyP]

Service man Scott said:

I wouldn't use alcohol or anything other than purified water to clean the myler as it could potentially damage the conductive coating.

Hi Tosh

Where does it migrate from and is it worth cleaning or a waste of time?

Thanks loads!

 

[Tosh]

The special graphite slurry is applied after stretching the diaphragm and serves as a 'backup' conductive coating in case of micro cracks or damage in the main vapor-deposited coating already on the diaphragm.
In the ML assy photo you can see the graphite has been applied using a mask to keep it off the spacers.
As for why the graphite migrates, my guess is it's a result of static forces and vibration pulling the now dry graphite off the diaphragm and concentrating it at each hole....