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Martin Logan ElectroMotion ESL panel segments sounds dead.

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AuBrisbane

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Hi from sunny Australia.

Got new pair of ML Electromotion ESL in 2014 connected to Yamaha AVR Avantege RX-A1030. Music source is Yamaha SACD CD-S2100, Blu-Ray source is Panasonic Ultra HD DMP-UBD900.
Have noticed that HF (high frequency) reproduction is starting to fade, especially during musical program.
Applying Yamaha YPAO auto calibration will produce reading of +12dB for HF adjustmet?
Have connected different AVR and got same results.
Sennheiser HD700 headphones are used to test imput signal to AVR and there is no problem with input signal.
On close listening ( ear close to panel segments) it is easy to hear that from 13 sections of the panel many of them are silent. Problem is observed on both Front speakers but one more than other.

My system also have 2 X ML DYNAMO 700W SUBS and ML C2 Centre speaker.

Went to suggested ML repairer in my area and repairer commented that he didn't have much contacts with ML speakers but is willing to look at the problem?
Have to go to see another recommended repairer in my city and if he is of same experience like one above, I am in trouble.

Is it possible that after hardly 4 years in mild use I have huge panel problems on both ESL speakers even expected life is 15 years?
What could be a possible problem, please?


Kind regards.

Zoran
 

roberto

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Hola Aubrisbane,

Your Electromotions speakers come with a 5 year factory warranty. Just take them to your dealer, and they will be fixed with no spare parts invoice.

Happy listening!
Roberto.
 

AuBrisbane

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Thank you very much Roberto.

Dealer has moved premises and I have found them, today.
They will come to my place and test two ESL speakers in few weeks time.

Kind regards.
Zoran
 

guynemer

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I am experiencing the same issues. Again. Not the first time. I already had a panel change, last year.

Now the issue starts to reappear one one panel. I am growing a bit tired of it. Aren't those panels supposed to be durable ??

Even if ML covers the warranty again, I also want to understand what could be the reason for this. I am using the power supplies provided by Martin Logan, nothing funky.
 

Jazzman53

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I am experiencing the same issues. Again. Not the first time. I already had a panel change, last year.

Now the issue starts to reappear one one panel. I am growing a bit tired of it. Aren't those panels supposed to be durable ??

Even if ML covers the warranty again, I also want to understand what could be the reason for this. I am using the power supplies provided by Martin Logan, nothing funky.
An ESL needs basically only two things to work: 1) AC voltage on the stators (audio signal) and 2) a DC biasing voltage on the diaphragm, which the stator voltages react against to drive the diaphragm. Both the stators and diaphragm must receive voltages, and the diaphragm must be capable of holding the voltage charge applied to it.

Swapping out the panel will determine whether the fault is in the panel, or the electronics interface (step up transformers & bias supply).

Assuming the fault is in the panel; either the conductive coating on the diaphragm has deteriorated (a gradual reduction in volume over time would be the symptom there), or there is a leak path (diaphragm shorting to a stator) draining charge off the diaphragm and preventing it from sustaining a full charge. A panel with a good conductive coating an no leak paths will continue to play for 5-10 minutes after unplugging the AC power cord.

A leak path could be a burn thru on a stator edge, or it could be simply dust buildup holding moisture and creating a conduction path from the diaphragm to a stator. Also; there could be a poor or corroded connection where the wire from the bias supply contacts the diaphragm (typically intermittent or no sound).

A burn thru would typically sound abrupt and intermittent and could be accompanied by audible and/or visible arcing (turn out the lights and look). Whereas a deteriorated diaphragm coating would result in constant but reduced sound output.

The panel may just be dirty. You might try vacuuming the panel or [cringe] washing it like others have done. If a good cleaning doesn't work, and you find no evidence of a burn thru, the diaphragm coating has likely gone bad.
 
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klouie

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An ESL needs basically only two things to work: 1) AC voltage on the stators (audio signal) and 2) a DC biasing voltage on the diaphragm, which the stator voltages react against to drive the diaphragm. Both the stators and diaphragm must receive voltages, and the diaphragm must be capable of holding the voltage charge applied to it.

Swapping out the panel will determine whether the fault is in the panel, or the electronics interface (step up transformers & bias supply).

Assuming the fault is in the panel; either the conductive coating on the diaphragm has deteriorated (a gradual reduction in volume over time would be the symptom there), or there is a leak path (diaphragm shorting to a stator) draining charge off the diaphragm and preventing it from sustaining a full charge. A panel with a good conductive coating an no leak paths will continue to play for 5-10 minutes after unplugging the AC power cord.

A leak path could be a burn thru on a stator edge, or it could be simply dust buildup holding moisture and creating a conduction path from the diaphragm to a stator. Also; there could be a poor or corroded connection where the wire from the bias supply contacts the diaphragm (typically intermittent or no sound).

A burn thru would typically sound abrupt and intermittent and could be accompanied by audible and/or visible arcing (turn out the lights and look). Whereas a deteriorated diaphragm coating would result in constant but reduced sound output.

The panel may just be dirty. You might try vacuuming the panel or [cringe] washing it like others have done. If a good cleaning doesn't work, and you find no evidence of a burn thru, the diaphragm coating has likely gone bad.

Hi Jazzman53:


I am the original purchaser of a pair of MartinLogan Monolith (I) speakers (serial #L309L-*) back in 1986. This pair of speakers have had their maintenance repairs over these past decades: I have already replaced the electrostat panels and woofers under the advice of retired tech, Jim Powers - so I have been able to keep these speakers going all these years. One of the replacement electrostat panels recently appears to be not functioning as it should. Jim had told me that the process for producing the panels had changed from the time when I made my original purchase (of having a conductive sprayed onto the membrane) to a new process (of evaporating the conductive onto the membrane - which should result in the panel not "wearing out" over time, as my original panels had done). His information sheet recommended swapping the panels to confirm if the problem was with the panels or if the problem was in "the woofer box." This time I did do the panel swap and concluded that both panels were still good; thus, as Jim noted, I believe I have isolated the problem to be in the woofer box, or as I concluded: more specifically with the power supply/crossover circuitry. I have been communicating with ML's tech support team, but they said they didn't have the resources to analyze or repair this circuitry, due to the Covid-19 situation. Thus, I have exhausted my queries with ML's support group; thus, I am asking if you have any advice to help me analyze and repair what might be a problematic power supply/crossover circuitry board.

I have obviously made an effort over the years to keep this pair of speakers going, and not about to give up after having to change most of it's guts already. I am about to retire and had hoped to spend my retirement time with these speakers that I have prized so much. FYI, these speakers are hooked up to a McIntosh MC2300 (supposedly an original model from the Grateful Dead's Wall of Sound setup used by them back then when they use to perform live - yes, this equipment is still running after all these years, as I would like the Monoliths to do, too). So I am a purveyor of legacy equipment that I maintain to appreciate the technical engineering that went into these components.

I am very disappointed that Martin Logan doesn't want to support its original legacy equipment as plenty of really established hi-end hifi companies still do support. I have moved on to another pair of "category A" speakers, as I won't purchase from a company that won't support it's legacy products. While I understand the issues with running a business. having been a financial analyst for over four decades now; but, there's a line that shouldn't be crossed if they want to keep old customers in their loyal buyers club; so with regret, I moved on to another company - that new company owner is great on email responding to issues on their equipment. Example, I believe the tweeters blew out, I emailed him and he went over a few test on diagnosing the issue and he concluded the tweeters were shot, but he did offer me the opportunity to purchase replacement diaphragms to replace the tweeter drivers. That was easy and very much appreciated - they now have a customer for life with me. ML lost me... But I digressed into venting my frustrations. Here's my issue: knowing that the problem is in one of the woofer boxes ( Jim's lexicon) - I would guess from your posting from yesterday, the problem is most likely the bias power supply in that box, since I know the panels still work after the swapping between the two woofer boxes. My question is how to repair the bias power supply, if I am correct. Despite my loss of confidence with ML, I would really like to try to revive this pair; they've been with me for 34 years. They do have their virtues that the new catagory A speakers don't have (the new pair really shines in the mid to highs, but the Monoliths can really cleanly handle high volumes very well). Hey Jazzman53, any advice or thoughts you'd care to share with me would be greatly appreciated.
 

Jazzman53

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I'm afraid I can't help you much. For one thing; my knowledge of electronics is pretty poor. And I think it would be difficult for anyone to diagnose your speaker remotely.

At least you've ruled out the panel, which would be a far more expensive repair.

If the panel is good and the speaker plays at all, even at low volume, it's more difficult to diagnose the problem. But if it doesn't play at all, that's easier.

If there is no output at all:
I would first verify whether the bias supply is working. There's no good way to do this unless you have a DVM with a high voltage probe (most volt meters would be instantly destroyed by the output from a working bias supply). I suppose you could probe the supply anyway and if it smokes the DVM, you could then assume it's working (ouch).

I'm not suggesting you do this but... not having an HV probe, and absent other options, I would check for bias supply output by simply shorting the diaphragm lead to one of the stator leads, to see if it sparks. If those two leads are brought within a quarter-inch of contacting, they should exchange a nice spark if the bias supply is working. That wouldn't tell me the voltage but it's probably OK if the spark jump at least a quarter-inch and its color is more blue or white than yellow.

The bias supply output can give you thrill if you're careless and touch it, but there's not enough amperage there do any harm.

ML power supplies are more complicated than the simple ones I use in my DIY speakers so I would not know how to diagnose anything beyond simple output.

If the bias supply is working, it's then it has to be the step up transformer, or possibly upstream in the crossover. And if there's a notch filter between the the transformer and stators, there could be a faulty resistor or capacitor there.

If the bias supply isn't working; I suppose I would just start probing components with a DVM, although you would need to pull one lead out of circuit to check capacitors and any transistors.

There are tons of Youtube vids showing how to checking diodes, capacitors, and transistor with a DVM.

I use an outboard digital crossover to drive my DIY speakers, and I have no experience with the passive crossovers used in ML speakers.

If there is output but something just isn't right:
I suppose in that situation I would use the components in the good speaker as a reference when probing components in the bad speaker, and look for something that measures differently.

Possibly better advice:
Post a description of your problem on DIY Audio Forum, in the Planar speaker section. There are some really sharp electronics guys there that may be able to help.

Good luck with your speaker!
Charlie
 
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Robert D

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I'm afraid I can't help you much. For one thing; my knowledge of electronics is pretty poor. And I think it would be difficult for anyone to diagnose your speaker remotely.

At least you've ruled out the panel, which would be a far more expensive repair.

If the panel is good and the speaker plays at all, even at low volume, it's more difficult to diagnose the problem. But if it doesn't play at all, that's easier.

If there is no output at all:
I would first verify whether the bias supply is working. There's no good way to do this unless you have a DVM with a high voltage probe (most volt meters would be instantly destroyed by the output from a working bias supply). I suppose you could probe the supply anyway and if it smokes the DVM, you could then assume it's working (ouch).

I'm not suggesting you do this but... not having an HV probe, and absent other options, I would check for bias supply output by simply shorting the diaphragm lead to one of the stator leads, to see if it sparks. If those two leads are brought within a quarter-inch of contacting, they should exchange a nice spark if the bias supply is working. That wouldn't tell me the voltage but it's probably OK if the spark jump at least a quarter-inch and its color is more blue or white than yellow.

The bias supply output can give you thrill if you're careless and touch it, but there's not enough amperage there do any harm.

ML power supplies are more complicated than the simple ones I use in my DIY speakers so I would not know how to diagnose anything beyond simple output.

If the bias supply is working, it's then it has to be the step up transformer, or possibly upstream in the crossover. And if there's a notch filter between the the transformer and stators, there could be a faulty resistor or capacitor there.

If the bias supply isn't working; I suppose I would just start probing components with a DVM, although you would need to pull one lead out of circuit to check capacitors and any transistors.

There are tons of Youtube vids showing how to checking diodes, capacitors, and transistor with a DVM.

I use an outboard digital crossover to drive my DIY speakers, and I have no experience with the passive crossovers used in ML speakers.

If there is output but something just isn't right:
I suppose in that situation I would use the components in the good speaker as a reference when probing components in the bad speaker, and look for something that measures differently.

Possibly better advice:
Post a description of your problem on DIY Audio Forum, in the Planar speaker section. There are some really sharp electronics guys there that may be able to help.

Good luck with your speaker!
Charlie
Your knowledge of electronics seems pretty good to me!
 

klouie

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Thanks for your recommendations. The trail to resolution has many paths, or as an instructor (in tax law) once stated: there are no experts, only varying degrees of ignorance (no insult intended! I certainly am ignorant or I wouldn't be asking; but I will keep knocking on every door - it's worth the journey, until I can find someone who is able to step up as a true expert (hello Jim Powers, where ever you may be).
 
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