Problem with Martin Logan ESL

[surfatwork]

Hi,

Need some help with my Martin Logan esls. One speaker is playing noticeably lower. Tried switching the channels, but it remained the same. So electronics are ok. Swapped speaker position - problem moved with the speaker.
I need to keep the balance knob almost a 3'o clock position to get sound coming from the middle. The problem speaker seems to be playing everything, just lower in volume.
DC resistance of speakers measures 6.4R for both.

Suggestions please?

 

[compaddict]

Swap the panels.

 

[surfatwork]

Swap the panels.

Did that. Problem moved to the other speaker. So looks like it is indeed the panel.
Can the panel become weak or something? What next?

 

[AllenB]

Moved to Planars & Exotics

 

[compaddict]

Replacement panels. Last time I checked they were very expensive (at least for the CLS).

 

[Boydk]

How old are they, and did you have them disconnected from mains for a while??
It´s not uncommon for older panels to go "weak", if you for instance disconnect them, go on vacation an reconnect them when coming back
Only solution I know of is panel exchange.

 

[surfatwork]

Hmm... Thanks for your input. Have emailed ML

 

[surfatwork]

How old are they, and did you have them disconnected from mains for a while??
It´s not uncommon for older panels to go "weak", if you for instance disconnect them, go on vacation an reconnect them when coming back
Only solution I know of is panel exchange.

Yes, they were disconnected for several months. They aren't very old (6yrs or so).

 

[CharlieM]

How old are they, and did you have them disconnected from mains for a while??
It´s not uncommon for older panels to go "weak", if you for instance disconnect them, go on vacation an reconnect them when coming back
Only solution I know of is panel exchange.

I had not heard before and that disconnecting an ESL for an extended period would cause it to deteriorate. Do you have any more info on that?

 

[rayma]

Try plugging both in and letting them charge continuously for a couple of weeks.

 

[CharlieM]

According to the ML website; all speakers built since 1993 have a sensor circuit that only charges the diaphragm when a music signal is present. That being the case; merely leaving the power cord plugged into the wall would not build up charge continuously.

 

[Andersonix]

Try squeezing or massaging the stators along the edge (where the wires are soldered to the panel) where the copper charge strip is in contact with the diaphragm.

LAST RESORT might be a shower....

 

[compaddict]

Shower trick! I did that once!

 

[Andersonix]

Did it work? Tell us more!

 

[compaddict]

Not for me.. New panels worked though!
Back when they were less than 1k it was kind of a bargain.

 

[Andersonix]

OP's panels are only 6 years old, so I wouldn't expect them to have accumulated so much dirt that a shower is necessary.

If you play a steady sound, when you scan your ear across the whole panel, are certain sections louder than others? Or is it a lower level overall from the whole panel?