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| [#3143] Quad ESL63 & 57 I am feeling very excited about my next trip to HK since there will hopefully be audition of Maggies from Limage, ESL57 and 63 from Patrick, jcml and Dennis, and other ESL users in HK ---------------------------------------------- Dear Hon......My friend in Waida confirmed that the price of ProAc 1sc has gone up due to current foregn exchange rates. Since I have restored the ESL63 and the sound quality exceeded my expectation, I no longer wanted to buy the ProAc 1sc. I will restore the one I just bought instead. Regds Patrick |
PCS100 正式會員219.xxx.xxx.3 |
2007-03-21 00:07 | |
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| [#3144] Quad ESL63 & 57 Dear Dennis I am really impressed by the price of your pair of speakers checked by Patrick. Where did you get them from? Regards |
powercord 正式會員 82.xxx.xxx.194 |
2007-03-21 00:12 |
| [#3145] Quad ESL63 & 57 I will restore the one I just bought instead. Correction: should read "I will restore the ESL63 I've just bought instead". |
PCS100 正式會員 219.xxx.xxx.3 |
2007-03-21 00:13 |
| [#3146] Quad ESL63 & 57 Hi Patrick Thanks for telling me. I haven't thought about the Proac Response 1sc since I returned to UK. The Response 1sc are very good speakers, but they are very expensive for what they can provide. I am really enjoying my LS3/5a at the moment. The midrange is still one of the best. Hon _____________________________________________________________________________________ Dear Hon......My friend in Waida confirmed that the price of ProAc 1sc has gone up due to current foregn exchange rates. Since I have restored the ESL63 and the sound quality exceeded my expectation, I no longer wanted to buy the ProAc 1sc. I will restore the one I just bought instead. Regds Patrick |
hifienthusiast 正式會員 80.xxx.xxx.12 |
2007-03-21 02:06 |
| [#3147] Quad ESL63 & 57 "Resistor are usually rated at power consumption i.e Watt." Blueray is right to point this out. High quality metal film resistors may do the job fine enough. But mind you, metal films do sound different from carbon ones. |
limage 正式會員 219.xxx.xxx.209 |
2007-03-21 07:52 |
| [#3148] Quad ESL63 & 57 Morning! As far as I know, like electric cables, resistors DO have voltage tolerance ratings. When you talk about over 3,000 volts in ESLs, it is better to be careful in chosing resistors. |
rcwy 正式會員 221.xxx.xxx.225 |
2007-03-21 08:01 |
| [#3149] Quad ESL63 & 57 In such a wax-filled box where resistors are spaciously separated from each other, the issue of voltage tolerance of resistors may not be critical. I leave it to electrical engineers to go on. :)  |
rcwy 正式會員 221.xxx.xxx.225 |
2007-03-21 08:20 |
| [#3150] Quad ESL63 & 57 I raised the question about high voltage resistors because I see here: http://www.mdw.ac.at/I101/iea/tm/scripts/jecklin/material/float.pdf |
jcml 正式會員 219.xxx.xxx.80 |
2007-03-21 08:57 |
| [#3151] Quad ESL63 & 57 Blueray is right to point this out. High quality metal film resistors may do the job fine enough. But mind you, metal films do sound different from carbon ones. ---------------------------------------------------- not really true. any film type resistor usually use laser to trim the resistance by cutting a groove along the film. this makes them not suitable for high voltage or current. try wirewound. |
drwkng 正式會員 210.xxx.xxx.111 |
2007-03-21 09:43 |
| [#3152] Quad ESL63 & 57 Posted by one parts seller: EHT Resistors Genuine high voltage high value resistors are hard to get. We stock the Philips range of high voltage resistors in 10 and 33 megohms. Rated at 3500 volts, these are ideal for diaphragm bias current limiting. A$1.75 US ($1.30)each 10 kv EHT resistors 100k - 470k Metal Oxide Resistors. Used in the secondary side of the audio transformer in series or parallel to provide frequency filtering to the ESL panels. A$2.25 US ($1.75) Each. Come from: http://www.eraudio.com.au/Components/components.html |
jcml 正式會員 203.xxx.xxx.249 |
2007-03-21 10:23 |
| [#3153] Quad ESL63 & 57 Thanks everybody sharing with their view of High Voltage Resistors. any film type resistor usually use laser to trim the resistance by cutting a groove along the film. this makes them not suitable for high voltage or current. try wirewound. Refer to page 8 of the document from jcml's link, "Projekt Floating 7603" One Thing Aduio claims they can provide upgrade kit consists of high quality (3.5KV Metal film ) replacement resistors. I really want to know what do they provide? May be it is just a marketing strategy? jcml, Thanks for your link, I did a search for "resistors" "high voltage", I couldn't find any relevant document in that article. |
Blue-ray 正式會員 218.xxx.xxx.66 |
2007-03-21 10:26 |
| [#3154] Quad ESL63 & 57 Blue-ray, There are high voltage resistors rated from 2W to 20W, mostly metal oxide or wire-wound. Please note in the 63, all of the resistors in the "cross-over" are film resistors. Could these account for the difference in sound between the 57 and 63?  |
cpsjj 正式會員 219.xxx.xxx.124 |
2007-03-21 10:44 |
| [#3155] Quad ESL63 & 57 Refer to page 8 of the document from jcml's link, "Projekt Floating 7603" One Thing Aduio claims they can provide upgrade kit consists of high quality (3.5KV Metal film ) replacement resistors. I really want to know what do they provide? May be it is just a marketing strategy? --------------------------------------------------- it is referring to metal oxide resistor. and yes you can get metal oxide resistor for high voltage as well. these are common. you can find them in say vishay catalogue. http://www.vishay.com/docs/31033/rox.pdf they go up to 45KV. |
drwkng 正式會員 210.xxx.xxx.111 |
2007-03-21 10:51 |
| [#3156] Quad ESL63 & 57 The one I bought before is cheap cheap 50 cents each. I didn't know there are high voltage resistors before. Sorry for my nuisance. I just like Dennis have the best parts to restore his 57 by our Patrick. |
jcml 正式會員 203.xxx.xxx.249 |
2007-03-21 10:54 |
| [#3157] Quad ESL63 & 57 it is referring to metal oxide resistor. and yes you can get metal oxide resistor for high voltage as well. these are common. you can find them in say vishay catalogue. High voltage metal film resistors are also available. See the link : http://dkc3.digikey.com/PDF/T071/1488-1491.pdf it goes up to 10,000 V DC, |
Blue-ray 正式會員 218.xxx.xxx.66 |
2007-03-21 11:07 |
| [#3158] Quad ESL63 & 57 t goes up to 10,000 V DC, --------------------------------- ha! so it is. i personally wouldn't risk to use it. i don't like the failure modes. i still think wirewound is a better alternative to both metal film and metal oxide for this particular job. |
drwkng 正式會員 210.xxx.xxx.111 |
2007-03-21 11:28 |
| [#3159] Quad ESL63 & 57 sorry to jump in, Any brothers have seen on web the electrostatis diy speakers? I'd seen once but cannot find the link now. |
diytfy 正式會員 155.xxx.xxx.45 |
2007-03-21 12:10 |
| [#3160] Quad ESL63 & 57 You can try this: http://www.quadesl.com/diy_esl1.shtml |
jcml 正式會員 203.xxx.xxx.249 |
2007-03-21 12:17 |
| [#3161] Quad ESL63 & 57 An interesting, informative but very long article by Gary J. Jacobson, a vet in ESL restoration. This article describes the broad details of a method for restoring or replacing the original Quad ESL diaphragm coating to its original specification. The description is mostly non-technical. Issues of materials obsolescence are addressed, and a number of apparent peculiarities in the original design explained. The methods described can be implemented with minimal, readily available equipment and chemicals. All surface resisitivity measurements quoted in this document were taken with a fully calibrated SR meter to ASTM D-257 standards. The accuracy is +/- 10%, and the repeatability is +/-5%. The Background Although almost anything, within reason, that can be spread on plastic can be used as a coating on an electrostatic speaker diaphragm, and work after a fashion; the original Quad ESL is particularly optimized in this respect, both in the chemistry and the choice of substrate material. Any old coating will not do the job quite as well. This is not to say that other coatings (e.g. graphite) cannot be used with success in original Quads. They can, and when properly implemented they produce excellent results also. However, these substitutes, by and large place extra drainage on the EHT power supply, which is already marginal in respect of current drainage. The original Quad speaker is a true marvel of subtle optimization within the materials / cost parameters of its day. Indeed, no polymer commonly available in production today would provide a markedly better material in their construction. I have only just begun to realise how subtle some of these optimizations are. The actual choice of which coating to employ in the original Quad ESL was/is part of this optimization. Alas, as all of us know, the original coating is no longer available to Quad, or anyone else. The original substance is not a secret. It was called CALATON and was made by I.C.I. (U.K.). This material was a soluble form of nylon. It could be dissolved in water/alcohol solution. The resulting solution was painted (literally) on the original Quad Mylar or Saran diaphragms that made up the moving element in the Treble and Bass panels respectively. The surface resisitivity, initially, achieved is 10^10 to 10^14 ohms per square. Surface resisitivity is dependent on coating thickness as follows: R(surface) = R(volume) / t where t is the thickness of the coating. Did Quad just put soluble nylon on the membrane or was there an additive of some kind? A key question, obviously. Can soluble nylon still be obtained anywhere in the world? - another key question. Will it actually work? The best question of all. Let's see about the answers to these questions then. Soluble Nylon Soluble nylon is still made by TORAY Inc. of Japan under the trade name of AQ-NYLON. When queried by e-mail regarding the product they are silent as the grave. Soluble Nylon was used in artifact restoration until the 1970's. It is somewhat disastrous in that application as it turns out, and its use has been discontinued. This may be why most previous manufacturers don't produce it anymore. Do not despair, there is a way around this problem, as I will describe later in this article. Additives Did Quad add ”doping” materials to the membrane material? This question can be answered by Quad, OR, by spectroscopic and gas chromatographic analysis. OK - out the door, down the road to the chemistry department. Ask the professional chemists to ”pretty please analyse this old piece of Quad diaphragm plastic and what's on it”. Offer free beer and other sundry bribes, wait for a week, and see. The answer? ”Yes, it's nylon and polyester, but we can't say if it has had a significant amount of additive. It might just be dirt.” Great guys(!) What can you expect after 20 odd years though? So, maybe Quad did, and maybe Quad didn't ”add” something. This issue was sidelined for later examination, as and if necessary. The Theory Firstly, unlearn, as I had to, the idea that static electricity means ”stationary electricity”. Think in terms of ”nett charge separation”, since this is actually the phenomena and also what we require. It is also nice if the charge does not move about on the membrane creating spurious capacitance variation and other bad happenings. F.V. Hunt's original mathematics shows that if capacitance variation is kept to ＜8% then distortions of all types are ＜0.5% at audio frequencies. Impressive, in a speaker. The next basic lesson to learn (or re-learn) is about the Triboelectric Series, (see below). Asbestos (Acquires More Positive Charge) Rabbit Fur Acetate Glass Mica Human Hair Nylon Wool Fur Lead Silk Aluminium Paper Cotton (ZERO) Steel Wood Amber Sealing Wax Hard Rubber MYLAR Nickel Copper Silver UV Resist Brass Gold Acetate Rayon Celluloid Orlon Acrylic SARAN Polyurethane Polyethylene Polypropylene PVC Silicon Teflon Silicone Rubber (Acquires More Negative Charge) We can see that Nylon is near the top of the series, and both Mylar and Saran are much further down. In effect, this means that electrons tend to leave the nylon and the Mylar tends to accept them. This produces a definite negativity in the Nylon. A close contact between Nylon and Mylar, as in a coating, guarantees that the electrons will stay very, very close to the Mylar ”side” of the pair. Quad coated the diaphragm on BOTH sides. Perhaps now, we can see why. The Nylon surface tends to be positive and the Mylar tends to be negative. There is NO bulk current flow to speak of because of the generally insulative nature of each substance. It is a ”nett separation of charge ”. The migration of charge through the bulk of the membrane is slow by any normal electrical standard. If a Quad membrane was coated with Nylon on one side only, then one side of the diaphragm would tend to be in slight negative charge deficit with respect to the other side. Quad then provided a small trickle charging source at 1500 and 6000 Volts for the respective diaphragms to provide the ”make up” of charge carriers in the system. I am sure that this is more obvious to us now, in an age of semi-conductors. In 1954-55, it was very clever indeed. So, it was NOT simply a matter of placing a high resistance coating on the membrane, but a PARTICULAR kind of high resistance coating that is triboelectically positive with respect to Mylar or Saran for the most desirable effect in this system. The EHT supply is designed to work ”hand-in-glove” with this specific combination of materials. A coating such as graphite will work, but excessive current drainage on the power supply will cause the membrane to oscillate (hum) at the line frequency. This is BAD. The hum can be overcome by putting large resistances in the EHT power supply line to a panel. This limits the current drain, and the charge, as a result is more closely confined to the surface of the membrane, eliminating the hum. Sound quality is still excellent, and this is a solution proposed by both Sheldon Stokes (U.S.) and Andrew King (U.K.). It is workable and expedient, but does not exactly restore the speaker to original condition. Other benefits accrue when these resistors are added and both Andy and Sheldon have these described in detail on their web pages. I highly recommend them as essential reading, and will not elaborate further here. The use of a large value charging resistor does not guarantee an absolute minimum of distortion at all sound levels across the normal audio spectrum, however. This is a consequence of the curvature of the membrane under dynamic conditions. As a result the capacitance will vary across the membrane - closer to the plates at the edges than in the centre. This means that a series resistance, large or otherwise, will cause variable RC time constant across the membrane. For small membrane excursions, this is negligible, so the technique is an excellent, cost-effective one for treble panels which (of course) experience low physical excursions. The ONLY way to effectively solve the problem is to place the high resistance on the diaphragm, so that a very high resistance is ”in series” with every individual capacitance, so to speak. Standard calculations indicate that a minimum of 10^9 ohms per square is sufficient. The Triboelectric necessities of life raise that value somewhat (nylon is used) in the narrow confines of this particular speaker. Conveniently, this enables the designer to lower the diaphragm to stator spacing and increase the efficiency of the device overall. This is another good reason, in addition to low distortion, for a very high resistance coating. The Practice Maybe TORAY Inc. will reply to my e-mail about the soluble Nylon, maybe not. Please feel free to contact them, they are on the web. If available at a reasonable price, it would be a valuable resource. DIY Soluble Nylon? Yes! Nylon is ”soluble” in Phenol/Water, Phenol/Methanol and 90% Formic Acid to name a short list of chemicals. An organosol is formed. Strictly, this is a kind of suspension, but let's not quibble about that since it won't be a problem in practice. Recipe Materials 25 grams Phenol (White, Crystalline solid, AR grade preferred) 150 ml water (tap water will do, distilled or demineralised is better) Nylon Fishing Line (not gel spun polyester!) N.B. Phenol should be handled with care. Wear gloves, and mix it in a well-ventilated work area. Phenol vapours are slightly flammable at elevated temperatures. Method Heat the 150 ml of water in a glass beaker to about 50 degrees Celsius. This temperature is not critical. We want pretty hot water but not boiling. Add the Phenol crystals to the water in 5 gram lots with constant stirring. Wait for each to dissolve. Chop up about 5 grams of NYLON fishing line (not critical again), into 1 cm pieces and drop into the solution about 0.5 grams at a time. Keep stirring with a glass rod over heat, but avoid boiling the solution. Stir for 15 to 20 minutes until all the nylon ”goes into solution”. Put the solution aside to cool to room temperature. You will see it separate into a thin dense layer, and a thick less dense one. Store this 'organosol' in a glass bottle with a resistant plastic stopper or glass stopper. The ”solution” made above is in fact an 'organosol' which is a kind of dual phase suspension (I'm told). It will, given a short time at rest, begin to separate into two obvious layers. The amount of nylon you have dissolved is indicated by the thickness of the lower layer. The thicker it is, the more nylon you have in 'solution'. Hence you must SHAKE WELL before and during use. This shaking process creates a suspension of phenol/nylon in phenol/water as small droplets. N.B. Phenol is also known as 'Carbolic Acid', and was used as the first hospital antiseptic/disinfectant. It is mildly corrosive. You should keep it away from skin and eyes as much as possible at these concentrations. It has a pronounced and distinctive smell, and prolonged vapour inhalation (hours and hours) can be harmful. It is very harmful if you drink it!! Don't be put off, normal care will avoid accidents. An alternative to aqueous phenol is Methyl Alcohol and Phenol. This vapourises from the work surface better and faster, but I prefer to avoid one more potentially flammable chemical and dry the coating with a hair dryer. Update (June 2000) BTW, I have found that it is possible to make Nylon (alone) dissolved in Methyl Alcohol/Phenol work as a diaphragm coating quite well without the need to 'dope' it at all. The ”dissolved” nylons in end-amine group solvents seem to provide a slight 'etch' into the polyester as well. So I think that the coating will actually stay on for longer than the original CALATON. For folks who don't want to mess with all these chemicals, there is a DuPont product known as ELVAMIDE which is an alcohol soluble Nylon, but I don't know if it can be bought in small quantities. The Application You can apply the material produced above in a fairly direct way to the Mylar membrane as follows: Set out the work area with the Mylar diaphragm to be coated, using your preferred method. Shake the bottle of organosol you have produced above until it appears as a uniform, white, milky coloured liquid. Put some gloves on! Open the garage window!! Wet part of a paper towel by closing the mouth of the bottle off with the towel, and shaking until the organosol wets the folded towel. Wipe the wetted towel in a side-to-side motion across the width of the diaphragm, and move down the diaphragm in an overlapping zigzag fashion until you cover it. I recommend that you recharge the towel at least twice when doing a Bass panel diaphragm and once when doing a Treble panel. Your mileage may vary - as they say. The material will sit on the polyester as a streaky set of lines of droplets. It is as if you had a very bad windscreen wiper on your car. This is OK! Dry the membrane as you go with an ordinary hair dryer set to LOW heat. We don't want ot heat shrink the Mylar by accident at this point. The Nylon coating will dry to a whitish, streaky, thin-in-parts finish. Re-coat if you like, but don't expect it to ever look ”even” or ”uniform” - It won't. The Nylon will adhere to the Mylar like tar to the proverbial tomcat. Guess what? It looks exactly like the original ”sloppily applied white-paint-like substance” that people talk about when re-building old Quad panels and membranes. The smell of Phenol will linger for days! Don't worry about this, since when the panel is re-sealed inside the dust covers with a good tape all around, you won't notice an odour at all. You could also leave it in a protected out-of-doors area for the smell to dissipate for a day or so too, and then seal it up - take your pick. DO COAT BOTH SIDES OF THE DIAPHRAGM! Does It Work? Yes. However, you must re-install the EHT supply bolts exactly as they were. The bolts I refer to are the two 12mm x 2mm bolts that hold the EHT wire onto the panels (Treble or Bass). As it happens, they just punch straight through the diaphragm, and this is what Quad intended - plus the fact that it is a lot faster during manufacture! The idea is NOT to achieve a good, solid contact with the membrane. Do not use little bits of foil, et cetera., to do this. With a different membrane treatment, this may be OK, but not in this case. These fine (2mm dia.) bolts sit in the centre (approx. and automatically) of a 3 to 3.5 mm diameter rivet and panel hole. I suspect these two rivets are a mechanical device to cause simple automatic centring of the bolts. The bolts touch the diaphragm physically, but we are not trying to create a classical electrical circuit here. This is a very, very high resistance contact, at 'best'. A cylindrical radiator (bolt) is placed so that it radiates electric field to the surroundings across a very tiny air gap (in the main), and this supplies the ”make up” charge on the diaphragm. The triboelectrical differences between the nylon and polyester take care of the rest. In other words, don't try to set it up in terms of a classical current flow. It doesn't work like that, and trying to make it work like that is extra effort and counter productive. A diaphragm coated in ”pure” nylon as done above will take a long, long time to charge fully - sounds just like a Quad ESL again, doesn't it? In fact, too long. We know that the original Quad membranes would charge to a useable level in one to five minutes. Although we also know that if Quads are left on, the sound continues to improve for days, especially the mids and highs. I strongly suspect that this is due, in the case of the original, factory diaphragms to partial coating loss with age, and the fact that the distribution of charge in the nylon becomes more ”even” with continuous charging on a ”good” membrane. In any case, this led me down the path of additives that Quad might have used to speed up the initial charge rate. To cut a long story short - to get an acceptable charge rate - add some anions permanently to the Nylon coating. In practice, doping the membrane with anions is simple. Take about 10ml of the organosol you prepared previously. Add 4 ml of hand soap containing Sodium Laurel Sulphate. I had this done in a lab, but I have done it with a household product with the same result. Coat a diaphragm in the same way as before with this ”doped” organosol. Dry well using the hair dryer as before. Measure the surface resistance! If it is anything, anywhere below 10^10 ohms per square, polish the surface off with a dry paper towel, as hard as you like and measure again. If this fails to raise the resistance, then 'strip' the surface with the original 'undoped' (no soap in it) organosol to raise the resistance again. The surface will increase in resistance to 10^10 to 10^12 ohms per square. It will NOT be uniform across the entire membrane, and it doesn't need to be. It isn't in the factory membranes either, should you be wondering. In fact completely removing and drying the soapy nylon material seems to be sufficient. This absolutely minimal contamination seems to be locked into the nylon coating for the life of the nylon - a long time. What you now have is an essentially insulative, by modern ESD standards, layer contaminated with anions, sitting on another insulative layer. The effect is PERMANENT. I have completely 'stripped' the soap-loaded membranes with organosol until the surface measures 10^12 ohms per square. These membranes still charge rapidly and improve with time. They sound just like the originals. Caveats Don't be tempted to brush large amounts of the nylon organosol onto the Mylar. For one thing, if you don't know what fibres are in the brush, it may dissolve! Secondly, a very high phenol accumulation in a given spot for a few minutes can weaken the Mylar. I actually had to use a 95% solution to do this, and this recipe is a lot less than that. Wiping and drying immediately will fix the entire coating as permanently as the original - so expect only about 20 years service from it. Don't clean the EHT bolts with penetrating oil or silicone lubricants if they are a little corroded looking. I made this mistake - duh! This dramatically reduces their ability to create the small, uniform electric field where they 'contact' the membrane. Brush them with a small wire brush, and 'degrease' with isopropanol or other alcohol. In a pinch - buy a few new THIN bolts. Typical Diaphragm Data (as measured during trials of various diaphragm materials) Graphite Standard application with mechnical polishing only 10^5 to 10^7 ohms/sq Graphite Standard application with alcohol scrubbing 10^8 to 10^10 ohms/sq Hand Soap Wiped on and mechanically removed 10^7 to 10^9 ohms/sq Nylon Straight organosol 10^10 to 10^14 ohms/sq Nylon (doped) Organosol + Soap then stripped 10^11 to 10^14 ohms/sq Remember it's not just the high resistance, but the Triboelectric differences between materials that make this combination of materials work - and keep on working. The Diaphragm Just thought I'd send you a quick line regarding polyester film. I've been doing a few experiments with 6 micron Hostaphan (biaxially oriented film) and it seems to hold its original tension quite well. It will be ineresting to see how it fairs in the longer term, since this is the same thickness of film as in the original Quad. It is (alas) outrageously expensive, being about $AUD20 per metre !! I would like to emphasise that the Hostaphan film is just in the early testing stages, but it does have a very high tensile strength. |
cpsjj 正式會員 219.xxx.xxx.124 |
2007-03-21 13:09 |
| [#3162] Quad ESL63 & 57 Interesting. Seems there is another Patrick in Malaysia. http://diyparadise.com/yabb/YaBB.pl?num=1155560768/15  |
jcml 正式會員 203.xxx.xxx.249 |
2007-03-21 14:19 |
