Anyone have any experience with these speakers? I know they have the SF6 gas bags, and are a bit rare...before going to hear them anyone know what the approx cost would be in decent condition?? $1100 a bit much?
I have modded ML CLS and CLII, and Maggie Tympani IVa and Id, and also a Model1and Model 3 Acoustat...how would these compare?
Appreciate the advice...
I have modded ML CLS and CLII, and Maggie Tympani IVa and Id, and also a Model1and Model 3 Acoustat...how would these compare?
Appreciate the advice...
I gess you saw this....sope work great...but you have got to Diy the panels so thay can be opend.. but i feel all panes should be setup to be opened...thay lose output in short time from dust an crued on the mylar...so the DW...you get gas,et....goodluck
What conductive coating did Dayton Wright use on the mylar membrane after liquid soap failed?
Paul Young2004-02-23 22:23
After the membrane was stretched and bonded to one of the polystyrene stator frames (using a �welding� technique - the plastic was soaked in acetone until the surface softened and then it was pressed against hard the stretched membrane while the acetone evaporated and the plastic solidified) the coating was applied using a silk-screen method combined with a custom blended colloidal carbon based �paint�. We went to this paint due to problems with the soap coating just migrating over time off the membrane to somewhere (the stators?). A silk-screen was used to coat the membrane in thin stripes because we needed to keep the total resistance of the cell high enough that there would be close to zero charge migration across the surface at the lowest frequencies used (20Hz). If the surface resistance is too low, distortion is created as the membrane surface charge moves in response to the combination of the modulating electrostatic fields from the stators and the deflections of the membrane. However, we also wanted (with the XG-10) to change the coating from �soap� to make it far more reliable and resistant to changes over a target operating life of 20+ years. We tried quite a variety of designs and chemicals to achieve the goals of: high ohms-per-square uniformity of resistance over both the surface and from cell-to-cell very high bonding strength to the membrane. In the end we had to blend our coating to a lower ohms-per-square resistance value than was desired - to achieve the degree of uniformity over the surface and from cell-to-cell. My memory isn't great on this part, but I think we were trying for a +/- 10 or 20 percent variability in both at max.. Had we used this coating over the entire surface, the cell resistance would have been too low and the forces on it would modulate at low frequencies causing waveform distortion. So we designed a simple silk-screen that put stripes of coating on the membrane. At each end of the cell (the short sides) there was a �buss bar� of coating deposited that ran the width of the cell and was about 1 cm. wide. These coating buss bars were connected to each other along the long dimension of the cell using a series of parallel stripes about 1 mm wide separated by about 1 mm (a 50% coating density in effect). Using this method of coating we could achieve the target range of cell resistance. The raw material colloidal graphite coating that we used was purchased from a company called Atcheson (Atchison?) Colloids in the USA. We used some pretty evil solvents with it to both dilute it down to the correct viscosity for silk screening as well as to supply the chemical aggressiveness required to attack the mylar membrane to achieve a good bond strength after it evaporated. I will do my best remember the chemicals and resistance values - but since I have no notes left on these - don't blame me if they are not correct. They will be approx. at least: Solvents used with the colloidal graphite - hexanone(?), and Methyl Ethyl Ketone (M.E.K.) that is a base solvent for many commercial adhesives. NOTE - these things are very bad to inhale - be extremely careful - work outdoors if possible, and use an expensive organics suited air mask or separate clean breathing air supply!! Resistance values - basic coating (no stripes) was approx. 100K ohms/square, cell resistance (end-to-end) was approx. 100 Meg. ohms - not counting the series fixed carbon �safety� resistor (re catastrophic arcing) that was connected between the EHT supply and one end of the cell at the bus bar strip. The other end of the cells stripes where they met the bus bar stripe was left floating. The design was a success re coatings because they were uniform, the distortion was very low, and nothing could remove that coating once it dried. I have a friend who is still using his XG-10s today and I built them for him in 1977. Hope this helps you.
What conductive coating did Dayton Wright use on the mylar membrane after liquid soap failed?
Paul Young2004-02-23 22:23
After the membrane was stretched and bonded to one of the polystyrene stator frames (using a �welding� technique - the plastic was soaked in acetone until the surface softened and then it was pressed against hard the stretched membrane while the acetone evaporated and the plastic solidified) the coating was applied using a silk-screen method combined with a custom blended colloidal carbon based �paint�. We went to this paint due to problems with the soap coating just migrating over time off the membrane to somewhere (the stators?). A silk-screen was used to coat the membrane in thin stripes because we needed to keep the total resistance of the cell high enough that there would be close to zero charge migration across the surface at the lowest frequencies used (20Hz). If the surface resistance is too low, distortion is created as the membrane surface charge moves in response to the combination of the modulating electrostatic fields from the stators and the deflections of the membrane. However, we also wanted (with the XG-10) to change the coating from �soap� to make it far more reliable and resistant to changes over a target operating life of 20+ years. We tried quite a variety of designs and chemicals to achieve the goals of: high ohms-per-square uniformity of resistance over both the surface and from cell-to-cell very high bonding strength to the membrane. In the end we had to blend our coating to a lower ohms-per-square resistance value than was desired - to achieve the degree of uniformity over the surface and from cell-to-cell. My memory isn't great on this part, but I think we were trying for a +/- 10 or 20 percent variability in both at max.. Had we used this coating over the entire surface, the cell resistance would have been too low and the forces on it would modulate at low frequencies causing waveform distortion. So we designed a simple silk-screen that put stripes of coating on the membrane. At each end of the cell (the short sides) there was a �buss bar� of coating deposited that ran the width of the cell and was about 1 cm. wide. These coating buss bars were connected to each other along the long dimension of the cell using a series of parallel stripes about 1 mm wide separated by about 1 mm (a 50% coating density in effect). Using this method of coating we could achieve the target range of cell resistance. The raw material colloidal graphite coating that we used was purchased from a company called Atcheson (Atchison?) Colloids in the USA. We used some pretty evil solvents with it to both dilute it down to the correct viscosity for silk screening as well as to supply the chemical aggressiveness required to attack the mylar membrane to achieve a good bond strength after it evaporated. I will do my best remember the chemicals and resistance values - but since I have no notes left on these - don't blame me if they are not correct. They will be approx. at least: Solvents used with the colloidal graphite - hexanone(?), and Methyl Ethyl Ketone (M.E.K.) that is a base solvent for many commercial adhesives. NOTE - these things are very bad to inhale - be extremely careful - work outdoors if possible, and use an expensive organics suited air mask or separate clean breathing air supply!! Resistance values - basic coating (no stripes) was approx. 100K ohms/square, cell resistance (end-to-end) was approx. 100 Meg. ohms - not counting the series fixed carbon �safety� resistor (re catastrophic arcing) that was connected between the EHT supply and one end of the cell at the bus bar strip. The other end of the cells stripes where they met the bus bar stripe was left floating. The design was a success re coatings because they were uniform, the distortion was very low, and nothing could remove that coating once it dried. I have a friend who is still using his XG-10s today and I built them for him in 1977. Hope this helps you.
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Be caerefull check the foam surrounds on the subs rots. $1100 in good condition is OK.
Fully gassed they have a very nice bottom end, a double pair stacked was very good...
I have 5 pairs of Dayton Wright cells - 2 good pairs XG10, 2 XG8 with bad cells, 1 XG10 mk 2 that need new cell, 2 subs that need new cones, the SF 6 gas tank and regulator, spare HV cables etc, spare transformers, 1 IM 11 , parts to build 2 IM 10, etc , new mylar for cell covers, - looking to sell the lot - 1300 lbs of electrostatic parts ---
Fully gassed they have a very nice bottom end, a double pair stacked was very good...
I have 5 pairs of Dayton Wright cells - 2 good pairs XG10, 2 XG8 with bad cells, 1 XG10 mk 2 that need new cell, 2 subs that need new cones, the SF 6 gas tank and regulator, spare HV cables etc, spare transformers, 1 IM 11 , parts to build 2 IM 10, etc , new mylar for cell covers, - looking to sell the lot - 1300 lbs of electrostatic parts ---
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Are the subs able to work on any speaker or made to work with only the DW XG-10?? Are they passive?
The DW Subs are a 4 ohms load with passive crossover with 2 x 9 or 10 inch woofers with SF 6 in sealed bags in the boxes to lower the cutoff frequency. Could work with other speakers too. They are 4 ohm loads which parrallel with the high (30 to 60 ohms or so) low frequency impedance of the DW cells so not too bad a load when combined with ESL's .
With other speakers the 4 ohm subs in parrallel with likely 4 or 8 ohm main speakers means you need a very good high current amp to drive the combination.
With other speakers the 4 ohm subs in parrallel with likely 4 or 8 ohm main speakers means you need a very good high current amp to drive the combination.
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Paul Young was the guiding spirit of the Dayton-Wright design for the last half-dozen years till the demise of Leigh Instruments.
I've run my XG-8s (I think) for about 30 years - most of that with a DD high-voltage amp. They seem pretty sturdy, unless you have a cat.
I've never heard a better way to generate music sound waves ever, at least across the sound spectrum excepting top and bottom 1 - 2 octaves. If you have adequate bias and the drive voltage, the cells (and most of the rest of the system like the welded frames....) are a purist's dream and make Quad and other commercial cells seem puny and they look slapped together from spare parts as compromises.
Ben
I've run my XG-8s (I think) for about 30 years - most of that with a DD high-voltage amp. They seem pretty sturdy, unless you have a cat.
I've never heard a better way to generate music sound waves ever, at least across the sound spectrum excepting top and bottom 1 - 2 octaves. If you have adequate bias and the drive voltage, the cells (and most of the rest of the system like the welded frames....) are a purist's dream and make Quad and other commercial cells seem puny and they look slapped together from spare parts as compromises.
Ben
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Just out of curiosity:
freons, R116 in particular, have about the same properties as SF6
Did anybody tried to retrofit Dayton-Wright with freon instead of original gas?
freons, R116 in particular, have about the same properties as SF6
Did anybody tried to retrofit Dayton-Wright with freon instead of original gas?
Interesting idea. Very useful if feasible. I don't know. But those little cans for re-charging automobile or home air-conditioners likely contain some oil and other contents with real poor audio fidelity. Not to mention other regulations surrounding freon these days.
On another thread ("If you had a lot of panels...."), I am inquiring about making a wall-of-sound out of DW cells. I think the cells sound better without the gas and enclosing films (and achieve best sound I've made with a direct-drive high voltage amp). Naturally with the gas gone, you lose the benefits of that concept (bass, high voltage bias, freedom from dust and humidity, annual pressure adjustment... megaphone effect).
But you (or often, your cat) could remove the enclosing films. (Perhaps alexberg could explain the health risks of working with these gases.... hope so.) I don't know if the DW bias voltage can be turned low enough to work without the gas. Betcha you'd get good sound that way, even if you'd need a few more horsepower from the amp.
Ben
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I think the freon used now for auto use is R-134a.
R-11, R-12 R-113 was also used at some time or another.
I do not know anything about R-116...
R-11, R-12 R-113 was also used at some time or another.
I do not know anything about R-116...
I would not though use modern refrigerants which are mostly hydrocarbons - so they are highly flammable.
Ever wondered what happens if you overheat non-stick frying pan? In contrast freons are used as extinguisher media...
There is such thing as RCl: Refrigerant Concentration Limit. GGL it. Freons are inert as most fluoride organic is...
On the other hand you probably have a quart or even more of liquid refrigerant in your house and it seems OK if it leaks.
How much volume does panel at question have?
Molecular weight of r116 is around 150 which means that 1 mole 22.4 liters has a weight of 150 grams.
P.S.
Xenon is also a heavy nobel gas but it's probably pretty close to unobtanium
EDIT
P.P.S. Another thing to consider would be tg delta or dielectric losses of a gas.
Ever wondered what happens if you overheat non-stick frying pan? In contrast freons are used as extinguisher media...
There is such thing as RCl: Refrigerant Concentration Limit. GGL it. Freons are inert as most fluoride organic is...
On the other hand you probably have a quart or even more of liquid refrigerant in your house and it seems OK if it leaks.
How much volume does panel at question have?
Molecular weight of r116 is around 150 which means that 1 mole 22.4 liters has a weight of 150 grams.
P.S.
Xenon is also a heavy nobel gas but it's probably pretty close to unobtanium
EDIT
P.P.S. Another thing to consider would be tg delta or dielectric losses of a gas.
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Too late to edit
In regard to SF6 safety:
arcing or corona can produce disulfur decafluoride (S2F10), a highly toxic gas, with toxicity similar to phosgene.
Source: https://en.wikipedia.org/wiki/Dielectric_gas
In regard to SF6 safety:
arcing or corona can produce disulfur decafluoride (S2F10), a highly toxic gas, with toxicity similar to phosgene.
Source: https://en.wikipedia.org/wiki/Dielectric_gas
Reviving this thread in the hopes of making some progress with freon as an alternative to SF6 in Dayton Wright speakers. It seems to be agreed upon that the density of freon is similar to SF6, so that's a good start. There is an excellent source of R134a in can form without oil...Walmart. A company called Speed Steed sells freon recharging bottles which have no other ingredients and no lubricating oil, and are also less than $10 per 12 OZ bottle.
I am calling out to the more scientific minded out there. I have found one reference showing R134a has dielectric property of:
at 50°C
Liquid 7.2 kV/mil
Vapour 6.7 kV/mil.
Redirect Notice
Also found this snippet in the Wiki article on R134a:
It can be used as an alternative to sulfur hexafluoride in magnesium smelting as a shielding gas.[9]
1,1,1,2-tetrafluoroethane is also being considered as an alternative to sulfur hexafluoride as a dielectric gas.[10] Its arc-quenching properties are poor, but its dielectric properties are fairly good.
If its arc quenching is poor, but better than air, that would still be a step in the right direction as arcing is the primary enemy in these speakers. Or am I completely barking up the wrong tree?
Now for the brainy part, can anyone make a comparison to the dielectric strength of SF6 at the same temp?
Secondly, and more importantly, would R134a break down the material of the panels? I am willing to experiment and potentially ruin one single panel if it will assist the entire Dayton Wright community in reviving this speaker line, I consider it to be a worthy sacrifice. But before I ruin one Id like to check more facts. Anyone?
I am calling out to the more scientific minded out there. I have found one reference showing R134a has dielectric property of:
at 50°C
Liquid 7.2 kV/mil
Vapour 6.7 kV/mil.
Redirect Notice
Also found this snippet in the Wiki article on R134a:
It can be used as an alternative to sulfur hexafluoride in magnesium smelting as a shielding gas.[9]
1,1,1,2-tetrafluoroethane is also being considered as an alternative to sulfur hexafluoride as a dielectric gas.[10] Its arc-quenching properties are poor, but its dielectric properties are fairly good.
If its arc quenching is poor, but better than air, that would still be a step in the right direction as arcing is the primary enemy in these speakers. Or am I completely barking up the wrong tree?
Now for the brainy part, can anyone make a comparison to the dielectric strength of SF6 at the same temp?
Secondly, and more importantly, would R134a break down the material of the panels? I am willing to experiment and potentially ruin one single panel if it will assist the entire Dayton Wright community in reviving this speaker line, I consider it to be a worthy sacrifice. But before I ruin one Id like to check more facts. Anyone?
I would leave out the SF6 - being a big DW Fan to my experience : the gas does not improve arc resistance in practise considerably (to outwheigh its cons) - as long as the amplifier is not clipping and there are no insects etc. in the air gaps the DW do not arc even at high level.
Clipping amps give high frequency harmonics, at higher frequencies air is much more prone to arcing..
to keep the gas in the speaker you need two more foils, which are sonically detrimental several aspects..
Clipping amps give high frequency harmonics, at higher frequencies air is much more prone to arcing..
to keep the gas in the speaker you need two more foils, which are sonically detrimental several aspects..
A crude measurement of an older (all plastic) cell (XG8??) puts the stator to diaphragm distance at .17 inch or 4.3 mm.
Some question about HV bias in different models. Might be as high as 17kV or maybe 12 kV. DW always put many megaOhms in the bias circuit, 17 at least.
DW construction is like military grade, mostly.
Ben
Some question about HV bias in different models. Might be as high as 17kV or maybe 12 kV. DW always put many megaOhms in the bias circuit, 17 at least.
DW construction is like military grade, mostly.
Ben
Secondly, and more importantly, would R134a break down the material of the panels? I am willing to experiment and potentially ruin one single panel if it will assist the entire Dayton Wright community in reviving this speaker line, I consider it to be a worthy sacrifice. But before I ruin one Id like to check more facts. Anyone?
http://www2.dupont.com/Refrigerants/en_US/assets/downloads/h45945_hfc134a_push.pdf
http://www2.dupont.com/Refrigerants/en_US/assets/downloads/h45945_hfc134a_push.pdf
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