I was looking into buying classic electrostatic speakers and noticed that the listings are full of Audiostatics, Quads, Martin Logans that either already had their foils replaced or are sold as in need of foil replacement, and there are companies in Germany ans Switzerland offering to do this. At the same time, I find rarely anything here on diyaudio.
So if a foil starts sagging, developing folds, crumbling or having a non-uniform metallization, it is clear you need to change it. At the same time, there are few pictures of such foils. I also read one the pages of one such company offering overhauls that there is a gradual loss of sensitivity due to electro-corrosion, cigarette smoke, dust, animal hairs.
So, in a non-smoking home and without obvious visible flaws in the foil, is this really a thing or just good marketing by repair shops?
I can imagine audiophiles worrying about foil maintenance and I have read many German forum posts where owner state how much better their speakers sound after foil replacement. There probably is space for wishful thinking.
A gradual loss of sensitivity, especially if it does not change the frequency response, may be hard to verify without measurement equipment and a reference, and it is not particularly worrysome (turn up the volume or the stator voltage).
So how inevitable is foil degradation really?
So if a foil starts sagging, developing folds, crumbling or having a non-uniform metallization, it is clear you need to change it. At the same time, there are few pictures of such foils. I also read one the pages of one such company offering overhauls that there is a gradual loss of sensitivity due to electro-corrosion, cigarette smoke, dust, animal hairs.
So, in a non-smoking home and without obvious visible flaws in the foil, is this really a thing or just good marketing by repair shops?
I can imagine audiophiles worrying about foil maintenance and I have read many German forum posts where owner state how much better their speakers sound after foil replacement. There probably is space for wishful thinking.
A gradual loss of sensitivity, especially if it does not change the frequency response, may be hard to verify without measurement equipment and a reference, and it is not particularly worrysome (turn up the volume or the stator voltage).
So how inevitable is foil degradation really?
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Quad ESLs use mylar. Over time the tweeter panels lose some tension. Replacing both of them restores the sound to original. This is inevitable with Quad 57s, however, it's not expensive and can be done at home with a little care and a soldering iron. Quad 57s are well worth keeping in good condition. The mid-range sound is the best I've ever heard. https://www.dadaelectronics.eu/uplo...SL-57-Revision-by-Sheldon-D-Stokes-Part-2.pdf
Usually it's not the mylar itself that causes problems, but the coating that looses conductivity. That results in lower or no output, making repair inevitable. In most cases it is not feasible to clean off the old coating and apply a new coating, so best option is to replace the membrame.
The mylar also gets dirty, even in a non smoker environment. And the material itself degrades and gets a little brittle over the years. This sometimes leads to the membrame tearing. Perhaps ozone is a factor here. Expect to get at max 10-15 years out of a rebuild, provided the speakers are kept in an area with clean air (non smoking and not in area's with heavy traffic nearby). And provided a good stable coating recipe is used.
The mylar also gets dirty, even in a non smoker environment. And the material itself degrades and gets a little brittle over the years. This sometimes leads to the membrame tearing. Perhaps ozone is a factor here. Expect to get at max 10-15 years out of a rebuild, provided the speakers are kept in an area with clean air (non smoking and not in area's with heavy traffic nearby). And provided a good stable coating recipe is used.
Hmm, so the pair I could buy is probably 17 years old and from a small company that no longer exists. It would take me a few hours to drive there. According to the owner, they still have their original foils and are running fine, except that one is 1-2 dB quieter.
So if I can't see any flaws and they sound fine to me, can I expect them to die on my shortly after?
So if I can't see any flaws and they sound fine to me, can I expect them to die on my shortly after?
They usually do not die suddenly, it's a slow proces so it stays unnoted for a long time. The output drops more and more, charging times increase. The user compensates by cranking up the volume. In some cases this can lead to other failures, I have seen a few Audiostatics were one of the audio transformer windings went open due to overdriving them.
After 17 years you can expect the membrame to be beyond it's best time. A difference in output between the channels is not a good sign to be honest. But there can be other reasons for that as well, such as a bad HV supply. In general it depends. The Quad 63 and later models for instance are sealed so those suffer less (but have other problems such as glue bonds breaking). An open ESL such as Audiostatic or ML will accumulate more dirt etc ont the membrame.
On the other hand, all ESL's can be rebuild for little money if you are willing to invest (a lot of) time and effort, so if the condition is fine otherwise and you can have them for a reasonable price, why not. For instance ER Audio sells excellent kits with mylar, coating, glue and everything else you need.
A few tests you can do before buying: Discharge them completely by disconnecting the mains supply and waiting for a day. Perhaps ask the seller to disconnect them beforehand. Then put an low volume audio signal on, plug in the HV bias and wait how long it takes for the volume to stabilize. Exact numbers are difficult to give as coatings and surface resistances vary wildy. The old Quad 57 can take up to a few hours. But most modern ESL's should charge up in a couple of seconds, anything under a minute should be fine. Differences between the channels are always a bad sign.
Also try listening with your ear close to the membrame and move your ear all over the surface. Listen for any hissing or cracking noises. Repeat the same test with low volume music playing. That will give an idea of how even the output is over the surface. If there are spots that play softer or louder, that is in most cases a clear sign of a bad coating.
After 17 years you can expect the membrame to be beyond it's best time. A difference in output between the channels is not a good sign to be honest. But there can be other reasons for that as well, such as a bad HV supply. In general it depends. The Quad 63 and later models for instance are sealed so those suffer less (but have other problems such as glue bonds breaking). An open ESL such as Audiostatic or ML will accumulate more dirt etc ont the membrame.
On the other hand, all ESL's can be rebuild for little money if you are willing to invest (a lot of) time and effort, so if the condition is fine otherwise and you can have them for a reasonable price, why not. For instance ER Audio sells excellent kits with mylar, coating, glue and everything else you need.
A few tests you can do before buying: Discharge them completely by disconnecting the mains supply and waiting for a day. Perhaps ask the seller to disconnect them beforehand. Then put an low volume audio signal on, plug in the HV bias and wait how long it takes for the volume to stabilize. Exact numbers are difficult to give as coatings and surface resistances vary wildy. The old Quad 57 can take up to a few hours. But most modern ESL's should charge up in a couple of seconds, anything under a minute should be fine. Differences between the channels are always a bad sign.
Also try listening with your ear close to the membrame and move your ear all over the surface. Listen for any hissing or cracking noises. Repeat the same test with low volume music playing. That will give an idea of how even the output is over the surface. If there are spots that play softer or louder, that is in most cases a clear sign of a bad coating.
Excellent, that is very helpful information. The ESLs in question are Capaciti, a small, now defunct German company. Interestingly, I have found nothing about owners saying they needed or were pondering foil replacement, nor listing, nor repair shops offering them. Either these are more trouble free, or they were sold in very low numbers. All I know is from a manufacturer white paper that they use 4.5 µm foil.
Do you have a link for ER audio?
Do you have a link for ER audio?
Yes, except that right above that contact form, there is a lbox saying that the company is out of business and that the pages are simply a mirror of their website as of April 2011.
Capaciti has been a member here for a long time, but it seems his profile is no longer accessible. You can still search his posts by this link: https://www.diyaudio.com/community/search/1393948/ Last posts are from 2010 I see.
ER Audio is in Australia, http://www.eraudio.com.au/index.html. Rob has a lot of knowledge and makes a high quality coating that is hard to find these days.
ER Audio is in Australia, http://www.eraudio.com.au/index.html. Rob has a lot of knowledge and makes a high quality coating that is hard to find these days.
The Capaciti panels are very reliable. However they should be operated with grillcloth to keep dust and dirt away. It is difficult to tell what the problem is. This requires measurements. If you are going to replace the Mylar be aware of the critical mechanical tension. Professional tefurbishers should have the tools for proper tensioning.
Just some experience I had buying a second hand Audiostatic......The speakers looked great with nice paint. The friendly owner knew little about their history, he bought it from someone else. At home I heard some ticking sounds. I didnt bother as I was planning to change the foil anyway. Once dissambled I noticed some weird stuff. At the end of the panels the wires were covered with black insulating tape. I removed the tape and saw the wires were cut like someone had been experimenting with the segmentatation. But it was even worse. The wires were burnt! Like the speaker had been on fire. I decided to put silicone kit around the damaged wire to improve insulation I put new foli in the speaker and kept the coating as far away from the outer part. However this was not enough. Insulation of the wire was still bad. Apparently the damage of the fire went way further than could be seen with the eye. I had to throw the panels away. For the little amount of money I still had good frames and electronics so I dont regret. I do have other examples of panels being danaged by 'refurbishers'. Lesson learned: if you dont know exactly what the panels are like from the inside and/or you are not buying from the first owner, pay as little as possible cause you never know what you are going to find. You may end up with carbage.
You may WILL end up with garbage. FTFY
Almost all second hand electrostatic speaker you find are a mess.
Lots of offerings that claim: "like new", "completely refurnished" or "done by a specialist". Beware.
Also first hand experience.
There are still some true gems to be found though, but they are becoming very rare.
Almost all second hand electrostatic speaker you find are a mess.
Lots of offerings that claim: "like new", "completely refurnished" or "done by a specialist". Beware.
Also first hand experience.
There are still some true gems to be found though, but they are becoming very rare.
Hi,
Michael Ehrlinspiel, the former owner and designer of the Capaciti dropped out of business a couple of years ago and moved to the USofA into his former field of business ... pharmaceutics.
He once told me that a former employee of his would provide for the service for his customers.
Unfortunately I don't know this source .... maybe searching the net could find him.
As mentioned before the Capaciti are well built, differing in a couple of procedures and tricks from simple glue-film-onto-stators 'designs'.
jauu
Calvin
Michael Ehrlinspiel, the former owner and designer of the Capaciti dropped out of business a couple of years ago and moved to the USofA into his former field of business ... pharmaceutics.
He once told me that a former employee of his would provide for the service for his customers.
Unfortunately I don't know this source .... maybe searching the net could find him.
As mentioned before the Capaciti are well built, differing in a couple of procedures and tricks from simple glue-film-onto-stators 'designs'.
jauu
Calvin
I own a second hand set of Quads, they sound incredible and I wouldn't call them garbage. Indeed, the opposite is true, they are treasured. Quad ESLs are easily repairable and maintainable and there are several businesses refurbishing them. It's audio gold waiting to be discovered. Just saying.
Don't forget with the quads, particularly the originals, they are decades old. The newest pair rolled off the line 40 years ago this year. And they were made in a time when plastics are in their infancy. I'm shocked that as many of them work as well as they do, for a consumer electronics device.
Sheldon
Sheldon
Cause we sre not used to consumer products lasting such a long time anymore. Some of those modern products are even designed to fail around 5 years while repair is made more and more difficult and expensive. Products from the past were build to last.
Not only do Quad ESLs keep working for a long time, they can also be maintained and rebuilt; indeed, there is a small industry that does so. I just replaced a water heater that went more than thirty years without a problem with the new ones that only last about four or five years between problems, despite costing much more now. We're all being ripped off by shoddy manufacturing from transnational corporations. Don't even get me started on crap made in China.
True, but when I go into Walmart, or 'Canadian Tire', everything is "Manufactured In China" and in my opinion, it's mostly crap. Even if it's not crap, undervaluing a currency in order to unfairly gain market share is crap. Just saying.
I have repaired many fault ststors by Er audio repair kit ,and it takes about 10 hour to fix each. You have to oder this kit from Er audio that including although 50 size advise
boo