| Rarkov |
Hi,
I am trying to source some 0.5mil (12.7micron) DuPont Mylar Film in the UK. After mistakingly quoting 2microns, I was knocked off my chair with £200 for 3mx49cm! When I finally got the correct data, it was quoted as £60 for 3mx30cm. Does this sound right? I need a larger width than 30cm though...Anyone know where to get it in the UK? It needs to be more like 50cm.
Please help! :bawling:
Thanks,
Gaz |
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| peterr |
these prices are absurd. Don't do it.
Look here for inspiration mylar |
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| kelticwizard |
I don't have the link handy, but someone on this forum has mentioned that someone in the US sells Mylar in a form that allows the builder to take a hair dryer and shrink it to a perfect fit once it is installed. He gives a supplier. I don't believe it was terribly expensive. You might try a search here on the forum.
The only thing I could add, apart from peterr's link, is here in the US they sell 2 foot by 3 foot sheets of Mylar for gift wrapping paper. They come in packages for a dollar. So the stuff should be cheap, assuming you can locate a supplier.
Good luck. |
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| ashok |
| quote: | | these prices are absurd |
Absurd is a very mild term for that price (60/- pounds).
I bought some from the US by mail order. I paid some US$20 I think some 3 years ago. Look for ESL on google and it will come up. I also bought two transformers from him. I am getting old, I forgot his name for the moment. It came folded ( not very sharp bends).
Its about 48 inches by 36 inches I think, maybe a bit bigger.
About the same time someone posted a message on the ESL web site ( can't remember where!) that he bought a whole roll in Tokyo for US$80 or 100/-. That was about 36 inches wide by over 100 feet - or was it meters! I remember thinking that my price was about 10 or 20 times more. Better you guys get together and see if you can buy left over rolls from electrolytic capacitor manufacturers.
Cheers. |
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| Steve M |
Hi Guys,
Try Rob Mackinlay - E.R Audio in Western Australia @ www.eraudio.com.au for all things ESL!
He sells 12um mylar for $1.10US per meter X 800mm wide. Also, supplies the dielectric coatings; transformers; rectifier blocks etc. and full range ESL speaker Kits at very reasonable prices.
Just a little tip, the 3.8um micron Mackinlay supplies is much better than any other thickness, being significantly more detailed and transparent sounding. I currently use and listen to E.R Audio's ESL-3 full range electrostatic loudspeaker...it's a wonderful speaker! Having much better transient response and micro-dynamic detail retrieval than any Quad ESL; Accoustat or Martin Logan I've owned or heard.
I will do a full review on the ESL-3 on this site in due course.
Regards,
Steve M. |
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| schpeltor |
| I got a 30" X 100ft roll (may be longer) .5mil from Professional Plastics for $40? I may have mixed some things up, but that info should be correct. |
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| MRehorst |
In the US McMaster-Carr has 5 or 6 micron polyester film, though the size may be limited. They also have perforated steel and aluminum sheets to use for the stators.
When you specify "Mylar" you get DuPont's product- Mylar is their brand name for polyester film. You can use any manufacturer's polyester film with excellent results. The film I use is called "Lumilar" and is made by a Japanese chemical company called Toray.
I would not make speakers using only a heat gun or hair dryer to tension the film. You can not get much tension that way so your speakers will exhibit very low sensitivity because you'll have to keep the bias voltage down to keep them from flapping. You will need to make a mechanical stretcher. Such a device will allow you to put a huge amount of tension on the film and run your bias supply at maximum possible voltage, thus giving you a speaker that can be driven to very loud levels by a "normal" power amplifier.
I have posted photos of a pneumatic stretcher I use on these forums - do a search. The stretcher is extremely easy to make and use and you won't regret trying it out.
MR |
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| Rarkov |
Hi,
Sorry for the delay in replying...
Thanks for all of your helpful posts. I have sent a cheque off to One Thing Audio (from a link in peterr's link). The owner is charging £30 for 10m...That far more like it. The is very little possibility for finding "scrap" / surplus parts for the ESLs around where I live, so it's going to be a long, slow and expensive exprience!
BTW, I've had a couple of ideas...
1) I have a dog and I am a bit jumpy about the idea of his wagging tail hitting things it shouldn't! (He's a v. long haired English Collie!!!) Am I able to mount ESLs on the wall - in the same fashion as a picture? I plan to have them either side of my fire place - but there is no room on the floor!
2) I'm also jumpy about touching things I shouldn't! ;) What is a sensible way to cover the front / back(?) stators? I thick acoustic foam as used on some normal loudspeakers OK? I assume this would keep out dust aswell?
3) Can I run my normal speaker cable to the ESLs if the electronics are in the ESL or do I need to beef them up a bit.
Finally...Mr Sanders seems to reason that no amount of power is enough for these things! I'm intending on making these things about 40cmx120cm (which should be about midrange). Are 140W monoblock amps (actually slightly higher due to rasied rail voltages - more like 160W) OK for this application?
Thanks very much for your help again!
Gaz |
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| MRehorst |
| quote: | Originally posted by Rarkov
1) I have a dog and I am a bit jumpy about the idea of his wagging tail hitting things it shouldn't! (He's a v. long haired English Collie!!!) Am I able to mount ESLs on the wall - in the same fashion as a picture? I plan to have them either side of my fire place - but there is no room on the floor!
>> Right against the walls is a lousy way to use ESLs. It will work, but don't expect hi-fi. ESLs like a lot of room behind them. It is a relatively easy thing to protect the speaker from the dog and vice-versa. Build a frame around the ESL panel that is a cm or two larger than the ESL is thick. attach dust covers to that frame, made from the same material you used for the diaphragms. These will keep hair and **** away from the drivers. Then cover with a chicken wire mesh (wire screen with big holes), then put a pretty piece of thin cloth over it. Make sure the dust covers are tight and have a little room to move. Wrinkles will make rattling noises on bass notes.
2) I'm also jumpy about touching things I shouldn't! ;) What is a sensible way to cover the front / back(?) stators? I thick acoustic foam as used on some normal loudspeakers OK? I assume this would keep out dust aswell?
>>> see above.
3) Can I run my normal speaker cable to the ESLs if the electronics are in the ESL or do I need to beef them up a bit.
>>> I don't know what your definition of "normal" is, but 12 ga zip cord is about as good as it gets (wait, I have to zip up my asbestos suit...).
Finally...Mr Sanders seems to reason that no amount of power is enough for these things! I'm intending on making these things about 40cmx120cm (which should be about midrange). Are 140W monoblock amps (actually slightly higher due to rasied rail voltages - more like 160W) OK for this application?
>>> 140W is plenty, assuming you are using reasonable ststor thickness and bias voltage. I also agree that you can never have too much power available. I run my ESL 63s on 200W/ch normally. Recently I have hooked up an LM3886 amp I built (about 30W/ch)and they play loud and sound great.
Thanks very much for your help again!
Gaz |
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| MRehorst |
Flat panel ESLs are extremely directional. You probably won't want to sit them on the floor because of the problems involved in aiming them at your ears. Think about stands that get the panels up to ear level when you are seated in your favorite chair. That way they'll be up where you need them for best sound, and out of the way of the dog's tail and wee wee.
MR |
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| Rarkov |
Hi,
Thanks for your reply Mark. I've been looking at your website and I'm sourcing the parts for your 'safer' bias supply. Finding parts in the UK is difficult but there is a place is Germany (hivolt.de) that does them. I've asked for a quote for the G-40.
I went to the Audio Circuit yesterday because I like reading through texts about unusual speakers (such as ion tweeters). One of the circuits I went to was the Flat Panel circuit (now closed). Can anyone tell me how they differ / work. Are they safer than ESL? Easier to build? Sound as good? etc etc.
Just interested really.
Thanks,
Gaz |
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| peterr |
| quote: | Originally posted by Rarkov
1) I have a dog and I am a bit jumpy about the idea of his wagging tail hitting things it shouldn't! (He's a v. long haired English Collie!!!) Am I able to mount ESLs on the wall - in the same fashion as a picture? I plan to have them either side of my fire place - but there is no room on the floor! [/B] |
It is possible to mount them on the wall but not against the wall. In order to work well ESL's need to have considerable breathing space behind them (something like 1m would be nice)
| quote: | Originally posted by Rarkov
2) I'm also jumpy about touching things I shouldn't! ;) What is a sensible way to cover the front / back(?) stators? I thick acoustic foam as used on some normal loudspeakers OK? I assume this would keep out dust aswell? [/B] |
The stators should be well insulated to begin with (even Sanders says so these days). There is nothing to worry about then. If you use perforated metal it is best to have it powder coated. Alternatively you can make stators using insulated wire. It is a good idea though to use some cloth as cover to keep dust away and dampen the resonance frequency
| quote: | Originally posted by Rarkov
3) Can I run my normal speaker cable to the ESLs if the electronics are in the ESL or do I need to beef them up a bit. [/B] |
I use normal Cat5 speaker wire. Works a treat.
| quote: | Originally posted by Rarkov
Finally...Mr Sanders seems to reason that no amount of power is enough for these things! I'm intending on making these things about 40cmx120cm (which should be about midrange). Are 140W monoblock amps (actually slightly higher due to rasied rail voltages - more like 160W) OK for this application? [/B] |
It will be more than ample. It is much more important that the amp is stable into a low load. Esl’s tend to have very low impedance at high frequencies. It may be advisable to put a series resistor of 2 ohm to help the amp.
| quote: | Originally posted by Rarkov
Thanks very much for your help again!
Gaz [/B] |
you're welcome |
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| peterr |
| quote: | Originally posted by Rarkov
Hi,
I went to the Audio Circuit yesterday because I like reading through texts about unusual speakers (such as ion tweeters). One of the circuits I went to was the Flat Panel circuit (now closed). Can anyone tell me how they differ / work. Are they safer than ESL? Easier to build? Sound as good? etc etc.
Just interested really.
Thanks,
Gaz |
Don't know much about them but I found this:
Barry Waldron provided the following information:
I have had the opportunity of spending two afternoons with these speakers on two different occasions over the course of a year. The second pair of speakers were about five generations newer than the first pair.
I have also spoken with the designer, Klaus Zimmerman, and met him at the first session. He purchased several matching transformers from me.
"The company propaganda states that these are not electrostatic loudspeakers, however, in the broad sense, they are. The main difference is that the diaphragm is a self sealing electret element that does not get its HV charge externally. Otherwise, the speaker is comprised of two stators that act upon a diaphragm in push pull fashion by modulating a HV audio signal, just like an ESL. "
Barry Waldron |
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| Rarkov |
Hi,
Thanks for the info, peterr. :bulb:
Gaz |
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| MRehorst |
| quote: | Originally posted by Rarkov
I went to the Audio Circuit yesterday because I like reading through texts about unusual speakers (such as ion tweeters). One of the circuits I went to was the Flat Panel circuit (now closed). Can anyone tell me how they differ / work. Are they safer than ESL? Easier to build? Sound as good? etc etc.
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There are different ways to make flat panels. ESL are one way, ribbons (like Apogees) are another, and coils glued to flm like Magnepans is another way. The last two use magnets arranged on the surface of a perforated metal sheet to provide the "bias" for the speaker. The Apogee type ribbons use a metallic conductor arranged in a serpentine fashion on the surface of a plastic film. The audio signal goes through the metallic conductor creating a magnetic field that interacts with the one set up by the stationary magnets and the result is sound. The magnepan type glue coils of wire to a plastic film and wirk pretty much the same way.
Both are "safer" than ESLs because there is no high voltage involved. I suspect they may be at least as difficult to build as ESLs, though the electronics is much simpler because there is no HV bias supply, and no step-up transformer (though they may require a step down transformer, depending upon the geometry involved).
NOTHING sounds better than an electrostatic speaker, except maybe the original source. That's just my opinion, of course, but once you listen to some ESLs, you'll understand why so many speakers compare their performance to electrostatics.
MR |
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| Audiofanatic |
NOTHING sounds better than an electrostatic speaker, except maybe the original source. That's just my opinion, of course, but once you listen to some ESLs, you'll understand why so many speakers compare their performance to electrostatics.
MR, You'r 100% right!
Thats why I use ESL's myself!
I'v made my own ESL's a clone of the Final 1.4 but not so tall.
Regards,
Audiofanatic
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| Rarkov |
Of course you're right. I've never heard ESLs yet...and I'm dying to hear them!!!
I can't wait to build them. BTW, can the spacers between the diaphram and stator be made from ply wood? I have some lying around...
Thanks,
Gaz |
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| Audiofanatic |
Hi Gaz,
The best material is PVC or Plexiglas, you can use plywood but the problem is, wood will conduct when you use high voltage. I'v had this problem before.
I now use Plexiglas/acrylaat. Dont know the english name for this material.
Gr.
AF.
;) |
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| MRehorst |
NO! Do not use wood. Wood is not a good insulator.
Use almost any sort of plastic you can get. PVC is an excellent insulator and is sold in sheets, but some adhesives won't stick to it. PCB material (fiberglass) is a good insulator, and easy to glue, but difficult and hazardous to cut.
I made a set of speakers using PVC insulators. I bolted the stators to the PVC using nylon bolts. Works great, and the bolts force the holes in the stator sheets to line up for maximum visual transparency (unimportant if the drivers will be behind cloth).
Finding compatible materials and adhesives are the biggest problems you have to solve when making ESLs. Everything else is pretty easy.
MR |
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| Rarkov |
Hi,
Just to keep everything in one thread:
There seems to be alot of problems using glue to hold the diaphram and stators on to the spacers, due to irregularities. Now, at first glance this may well sound stupid, but is it possible to use double sided sticky tape? I would be able to tightly control the D/S spacing. I would then use alot of nylon nuts / bolts to hold the whole thing together... So the build up would be as follows:
Stator : Tape : Spacer : Tape : Diaphram : Tape : Spacer : Tape : Stator
All held together with alot of nylon bolts, every 50mm or so.
How does that sound / what are the problems related to this method?
Thanks,
Gaz |
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| Audiofanatic |
Hi Gaz,
You can do that without any problem.
But! Be shure to use the best tape you can buy!
I use the best glue there is, from BISON.
Are you going to make it with pvc isolated wire or with perforated metal?
I wish you luck with your plans.
Regards,
Audiofanatic |
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| Rarkov |
Hi,
Before I go on, it'd be rude not to let you know how beautiful your ESLs are!!! Fantastic work. (Or are they what you made clones of?) Either way - excellent! ;)
I have got the Mylar. I ordered it from One Thing Audio. I believe it is used for repairing Quad ESLs (66? Something anyway!). Unfortunatly it is about 23microns thick which is more than I wanted, but hopefully I should get quite a bit of tension.
I am sourcing some 1.5mm or 2mm acrylic for the spacers (about 1.7mm seems to be optimal but hopefull 1.5 bulked out with tape will do it). Finally, the stators are the only thing I haven't sourced. I am getting quotes on 1.5mm mild steel perforated plates with 50% coverage of 3mm holes. I will get them powder coated (only £25 for all 4!). One company quoted £80 for the mild steel!!!
Does this sound OK? Will it make much difference if a D/S spacing is 2.1mm instead of 1.7mm? Does that sound right by the way. Sounds like an awfully small gap to me!
Thanks,
Gaz |
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| Audiofanatic |
Hi Gaz,
The ESL's are the original ones, I'v made a clone of those.
The Mylar is to thick, you'll see when you'r ready to listen to your ESL's.
I can send you 4 or 6 micron if you want via a friend of mine, 80cm resp. 100cm wide.
The gap is o.k! the bigger the gap, the lower the db!
I'm going to bed now.
I'll continue tomorow
Audiofanatic.;) |
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| peterr |
| quote: | | Unfortunatly it is about 23microns thick which is more than I wanted |
This really is very thick. I can't imagine Quad uses this.
I use the 6 micron variety Audiofanatic speaks about and it is very good. It is also in the link in my first post (the stuff from MartinJan Dijkstra).
I too used tape to glue the mylar to the spacers but I have used glue (bisonkit it is called in holland) to fix the spacers to the frame.
My D/S spacing is 2mm. I would rather go to 2.5mm then to 1.5mm if you intend on using your ESL at or close to full range.
Make sure to have your metal powdercoated at least twice maybe even three times to create a thick enough insulation layer.
Also I read somewhere (did not test it myself) not to use black paint as it contains carbon particles (to make it black). This gives it a much lower resistance at these high voltages.
Good luck |
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| ashok |
I am also working on an electrostat. I just wanted to caution all those new to DIY and especially working with ESL's, be VERY CAREFUL about the voltages. Use rubber gloves when working with powered units. These devices can shock you VERY badly if not KILL you if you touch live parts. Remember that the ESL is a capacitor and so can store a charge at very high voltages. While these are highly resistive , the power transformer/power supply and step up transformer are especially lethal. With kilovolts around you can even blow a normal DMM !!
BE CAREFUL.
Cheers. |
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| Rarkov |
Don't worry. I'm exceedingly wary of Power Supplies. I had no prior knowledge of high power PSUs when I built my monoblocks with 500VA PSUs, but I did it, and I'm happy with them, but I certainly do not go poking around in them...or if I have had to quickly discharge large caps, it's been on the end of a long screwdriver! :idea: :eek: :cannotbe:
I will be even more wary of kV sized PSUs! Out of interest, if using a DMM with a step down resistor network, how far can I expect the PSU to spark to the probes (or me) when I go to measure them. Will there be a spark at all?
BTW: How much would people expect to pay for perforated sheet mild steel with the following specs:
2mm thickness (2000mmx1000mm)
50% hole coverage.
3mm hole at 4mm pitch
£72.76 per sheet (need 2!)
Thanks,
Gaz |
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| wrl |
Does anyone know where to purchase the audio step up transformers?? I tried the electrostatic loudspeaker exchange, but they seem not to be answering their e-mails and their phone line is disconected. HMMM methinks a bad sign.
Anyway, if anyone knows where I could get these it would be appreciated.
Thanks,
Wes |
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| ashok |
I think this is probably a bit like winding audio transformers for a tube amp. Only hitch is that it uses higher voltages on the secondary and so insulation schemes will be more important.
Has anyone started winding an audio output transformer yet ?
If you have never wound a transformer - it might be much better to buy one.
Cheers. |
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| 316a |
| quote: | Originally posted by ashok
I think this is probably a bit like winding audio transformers for a tube amp. Only hitch is that it uses higher voltages on the secondary and so insulation schemes will be more important.
Has anyone started winding an audio output transformer yet ?
If you have never wound a transformer - it might be much better to buy one.
Cheers. |
Why not try using a 240V:6V mains toroid ? After all these should be able to provide wide bandwidth and a turns ratio of 1:40 . With an ESL , bass will not be required so core saturation will not be a problem , should work (in theory) .
Rarkov : I'm also building an ESL . A good source for mylar is model engineering suppliers . My 5 micron mylar was £5.00 for a 10mx30cm piece . Farnell have suitable double sided acrylic tape and foam tape suitable for spacer adhesive . Is this what you were planning on using ?
316a |
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| wrl |
Wow, most of those transformers are well over $100 dollars.
I was hoping to spend no more than $75-$80 on each of them. Also, I don't need it to go lower than about 500-600 hz.
Anyone have any suggestions for places in the US?
Thanks,
Wes |
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| Alexander Rice |
| Using a mains transformer is probably not a good idea because thay are often made of the poorest grade of steel they can get away with. If you try feeding a mains transformer form a signal generator and measure the power in and out you find, unsurprisingly that they are most efficient around 50 Hz and drop off rapidly either side - i only tested to 1khz and already that was down by about 10dB from the 50hz peak - i dread to think what sort of thing happens at 20kHz. As frequency goes up you need thinner and thinner laminations to reduce eddy currents in the laminations. I would have thought you would be better re-winding an old output transformer. |
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| 316a |
| quote: | Originally posted by Alexander Rice
Using a mains transformer is probably not a good idea because thay are often made of the poorest grade of steel they can get away with. If you try feeding a mains transformer form a signal generator and measure the power in and out you find, unsurprisingly that they are most efficient around 50 Hz and drop off rapidly either side - i only tested to 1khz and already that was down by about 10dB from the 50hz peak - i dread to think what sort of thing happens at 20kHz. As frequency goes up you need thinner and thinner laminations to reduce eddy currents in the laminations. I would have thought you would be better re-winding an old output transformer. |
I've built my ESL panels now and have already tried a mains toroid as a step-up transformer . Even though I need to do more work with raising the polarising voltage to increase sensitivity , there appears to be nothing wrong with using one , in fact the top-end in comparable , if not better than with an 8k anode to anode valve output unit . Due to the construction of mains toroids , wide bandwidth is achieved , of course with EI transformers you will run into problems ! Why not repeat your tests with a mains toroid , you'll probably get at least 30k bandwidth
316a |
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| Alexander Rice |
| i did indeed test an EI type transformer - although the tests were not in connection with building speakers so i had no reason to retest a better trannie. I naturally assumed that the core geometry plays a relatively small part in the frequency response of the transformer, this may well not be true, althought i am sure it depends alot on the 'quality' of the particular transformer - ie. the type of steel used and the thickness of the laminations. That said, modern transformers with amorphous silicon steel laminations are already FAR superior to what was being used even 20 yrs ago. I'll run some tests tomorrow if i get the chance beacuse i have always been put off experimenting with valves due to the high cost of a suitable output trannie, if i can buy one 'off the shelf' in the form of an ordinary mains transformer or rewind one of the same to suit my needs i'll definitley be paying more attention to the possibility of home brewing a little valve amp (hell, i've got a 1000W trantmitting trode in the basement - that could make an 'interesting' amp...) |
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| 316a |
Go for it , you may be surprised :)
This evening I discarded the stepup transformers altogether and drove the ESL straight from the anodes of my amp via teflon capacitors :cool: This is definitely the way to go ! Luckily I only need to drive a 5"x20" treble panel . My current workshop amp only runs from a 220V rail though , time to build something with higher B+ and drive these things active . Interestingly the sensitivity of the ESL can be matched to the main unit (Jordan JX92 TL) by tweaking the polaring bias . ESL's are fun :nod:
316a |
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