The Audio Circuit
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The Audio Circuit web site (September 7, 2007): TAC The Audio Circuit is set up around 2000 with the goal to provide a free database on audio on the Internet. We have build a structure in which you, the visitor, can add information online. In this structure we are also able to provide manuals on brands and models that are no longer available via the regular channels.
We also sell Hostaphan and Elvamide, two essential materials to build electrostatic loudspeakers. In the future we plan to sell more parts to build your own electrostatic loudspeakers.
Elvamide coating Materials
We found a supplier for Elvamide , It is known to be a very good coating for membranes as it perfectly bonds to Hostaphan and Mylar and it has a very high resistance.This coating has a resistivity of 10^10 to 10^12 ohms per unit square. We sell it in quantities of 25 grams (enough for 300 cc). The material comes in granular form and it has to be dissolved in alcohol or in cheap, readily available "methylated spirits" (spiritus as it is called in Germany and the Netherlands). The material comes with detailed instructions on how to use it.
|Elvamide 25 grams (enough for 300 cc, enough to cover 4.5 m2 or 2.2 m2 when applied to both sides of the diaphragm) Package and shipping included||
Hostaphan can also be made conductive by using graphite. It can be bought in any hardware store. Buy the highest grade possible, the smaller the particles the better. Here is a little instruction on how to apply it:
- You need is a very smooth surface, a glass plate or a table or something.
- Make sure it is clean and stretch the Hostaphan by using tape all around.
- Mask the area you want conductive with masking tape.
- take very little graphite in the finest grain you can find at rub it into the Hostaphan using cotton balls. You can apply considerable force. The Hostaphan is extremely strong.
- Make sure you get a reasonable even greyish colour all over the membrane. It doesn''t have to be perfect which is impossible anyway.
- Now take some alcohol on cotton balls and remove as much of the graphite as you can, again by using considerable force.
You will end up with a very light colored membrane (hardly viewable) with a very high resistance.
The invention of Mylar by the US company DuPont in 1948 made it possible for Peter Walker of Quad to start developing his famous ESL 57. Later on Peter used Malanize, which is in fact the Brithish equivalent for Mylar. Mylar is Dupont''s trademark. Technical this material is called PETP. In Germany this material is produced by Hoechst and is called Hostaphan.
Hostaphan RE-6 (6 micron, 795 mm in width) is a perfect material to use as diaphragm material. It is the German equivalent to Mylar C, a tenselized PET film that will heat shrink for about two percent, ideal to get a perfect tension for your membrane. Please check out the data sheets if you need more detailed information.
We can also supply 750 meter rolls at a very affordable price. Ideal if you want to experiment or if you want to share costs with fellow ESL builders.
International Shipping notes
We ship from the Netherlands. Regarding shipping to International destinations, please carefully review the following information:
Shipping Internationally for this item allows for 10 day delivery to your country''s processing Customs, they will hold to inspect/pass from 0 days to up to 4 weeks. They will then release to your delivery address. It is best to plan for 6 to 8 weeks to deliver. It is arrives any sooner it is a bonus. There is noting that can be done on your end or my end to expedite this delivery. Only using UPS or Fedex could speed up delivery. Unfortunately this is way to expensive for small packages.
This is particularly the case for CANADA, AUSTRALIA, and parts of the UNITED KINGDOM. These areas seem to take a significantly longer timeframe to in-process parcels. If you pay a higher shipping rate to expedite the delivery, it only serves to get the parcel to your in-processing customs quicker. It will have no bearing on the time your customs handling of the package will take. Shipments outside the Netherlands may be subject to additional charges by your local governments, such as General Services Tax (GST) or Value Added Tax (VAT) as well as customs duties. These charges vary by country and the size of your order and are assessed by the governmental agency, and not by eBay or me as the seller. It is not possible for me to estimate these charges in advance. Please take these very important details into consideration and allow them to temper your expectation as to the delivery of your package. Having said the above: We very rarely encounter any problems with delayed packages. Almost all of our shipments are processed through customs without delay and without any additional costs.