"If you want to know if your insulation works without losses, you should setup an identical ESL without insulation to compare.
capaciti "
This is an experiment I would like to do someday.
The one thing that Roger Sanders told me ,that always stuck in the back of my mind, when we were talking about stator coatings (powder coatings was the subject) is " of course you want the highest dielectric strength but choose the one that has the highest dielectric constant even though it has a lower dielectric strength(volt per mil)".
Somehow I understand this but it is very confusing and I have never found any discussions of this or it being mentioned. jer
capaciti "
This is an experiment I would like to do someday.
The one thing that Roger Sanders told me ,that always stuck in the back of my mind, when we were talking about stator coatings (powder coatings was the subject) is " of course you want the highest dielectric strength but choose the one that has the highest dielectric constant even though it has a lower dielectric strength(volt per mil)".
Somehow I understand this but it is very confusing and I have never found any discussions of this or it being mentioned. jer
Hi,
sanders is right, thats why e.g. for wire stators PVC is one of the favourible insulation materials, while teflon is not.
I am no expert in coated perforated metal stators, but i guess it took ML a long way to figure out the best coating. A simple laquer is certainly not the perfect one.
Capaciti
sanders is right, thats why e.g. for wire stators PVC is one of the favourible insulation materials, while teflon is not.
I am no expert in coated perforated metal stators, but i guess it took ML a long way to figure out the best coating. A simple laquer is certainly not the perfect one.
Capaciti
Both the Acoustat White Paper and the Janszen patent discuss desirable insulation properties for wire ESLs.
I don't think voltage rating for the wires are brought up, but once you understand the basics you can work it out for yourself.
The Acoustat White Paper can be downloaded a few places, here are two:
http://www.audiocircuit.com/A-PDF/AA-Brands/A/Acoustat-ACO/GEN-John_Strickland_-A-EN2-941-ACO.pdf
http://www.integracoustics.com/MUG/MUG/tweaks/acoustat/technology.pdf
Janszen Patent US2631196
ELECTROSTATIC LOUD-SPEAKER - Google Patent Search
Referring to the attached figure taken from the Acoustat White Paper:
DC voltage
Ria & Rd form a resistive voltage divider for the applied bias voltage.
For a given bias voltage, you will maximize the voltage across the airgap if Rd is much smaller than Ria.
So you don't want a really good insulator for your insulation like teflon, otherwise most of the applied bias voltage will appear across the insulation rather than in the airgap.
PVC or Kynar are pretty conductive as far as insulation materials go.
AC voltage
Cag & Cd form a capacitive voltage divider for the AC voltage(music) applied to the stators.
For a given AC voltage, you will maximize the voltage across the airgap if Cd is much larger than Cag.
To make Cd large you want an insulation with a large dielectric constant like PVC or Kynar. Again, teflon would be a poor choice.
Voltage rating for wire insulation
If you choose a wire insulation that is somewhat conductive and has a high dielectric constant, the working voltage the insulation has to withstand (in a constant charge ESL) may be much less than you might think.
With Rd & Cd fixed by the insulation properties, the percentage of the applied voltage that appears across the insulation is a function of the airgap size. For ESLs with airgraps of roughly 1/16"(1.5mm) most PVC forumlations will have only 10%-15% of the applied DC & AC voltages appear across the insulation. So voltage ratings of 600V should be more than adequate for most PVC wire ESLs.
Kynar appears to be even better than PVC with both lower resistance and higher dielectric constant. But, it costs more and is not as readily available.
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The first set of panels that I built and dropped into My Acoustat 0ne plus 0ne's were Kynar 28 gage wire wrap 12 wires per linear inch. They worked perfectly and sounded much better than the stock panels had. They played for a couple of years till one of my kids decided to experiment with poking the cubes with a Popsicle stick and was creative enough to get a step stool to reach up high and poke up there too. A calm conversation about all the hard work daddy had done and would have to to again was all that was required, we never had a problem of that sort ever again. She is in University now and has a set of Stax in ear monitors of her own. Really surprised me at the time as even though I was upset about it I never had a thought to get angry. It's a good memory that I like to keep in mind.
Fortunate she didn't use a metal object! I've gotten used to warning people upon their introduction to the Acoustats that they have DEADLY voltages present and don't even THINK about touching them. The healthcare debate here in America has found me a great name for the speakers: Death Panels.
Nothing terribly deadly in a stock Acoustat with the Mk121 interfaces. High voltage, low current.
Strickland specifically stated that he used PVC because it is "leaky". He explained that he had built a version using 'good' insulation (ptfe) and they worked fine in relatively high humidity situations and not at all in very very dry (arizona) climates...
Fyi.
_-_-bear
Strickland specifically stated that he used PVC because it is "leaky". He explained that he had built a version using 'good' insulation (ptfe) and they worked fine in relatively high humidity situations and not at all in very very dry (arizona) climates...
Fyi.
_-_-bear
Hi Paul,
I've had good success bonding nylon coated magnet wire to phenolic by using hot melt glue. I tested several adhesives, including epoxies of a few varieties, and found that the hot melt glue held more reliably than anything else--by a significant margin. Of course the question of ease of application is another matter, but I finally came up with a system that seems to work. It's more labor intensive than it would be to use something like epoxy, though. Here's a link to some preliminary results.
Few
Few: I would be interested to know for reference exactly which kind of hot melt you found worked. I can get some and try it on some new pieces of Styrene louvre to see how it deals with the release agents and plasticizer in the Styrene.
On another topic the jig that I use is similar to yours but simpler. I use a threaded rod sunk into a slot in a square length of mdf with some epoxy to lock it in place. On the back side of this I have two staggered rows of 1/2 inch finishing nails set into pre drilled holes all tilted down about 15 degrees to act as hooks for the wire. I place one of these jigs at each end of the louvre and screw it down to a base rectangle of plywood just larger than the panel. Then with some shim stock stuck to the plywood I adjust the height of the louvre and give it a slight upward bow in the middle of the panel length. When I wind I just use hand tension as I go. The slight bow insures that the wires are all laying flat against the louvre surface ready to be bonded down. Cheap cheerful and easy. When you use the hot melt can you apply external heat after it is applied to make it flow out smooth to insure that none of the glue sticks up past the surface of the wire? Or is this even an issue. My experience with hot melts is that most are fairly thick and they tend to cool quickly and the ones I have used don't flow much if any. Will be interested to hear your comments. Thanks for the heads up.
On another topic the jig that I use is similar to yours but simpler. I use a threaded rod sunk into a slot in a square length of mdf with some epoxy to lock it in place. On the back side of this I have two staggered rows of 1/2 inch finishing nails set into pre drilled holes all tilted down about 15 degrees to act as hooks for the wire. I place one of these jigs at each end of the louvre and screw it down to a base rectangle of plywood just larger than the panel. Then with some shim stock stuck to the plywood I adjust the height of the louvre and give it a slight upward bow in the middle of the panel length. When I wind I just use hand tension as I go. The slight bow insures that the wires are all laying flat against the louvre surface ready to be bonded down. Cheap cheerful and easy. When you use the hot melt can you apply external heat after it is applied to make it flow out smooth to insure that none of the glue sticks up past the surface of the wire? Or is this even an issue. My experience with hot melts is that most are fairly thick and they tend to cool quickly and the ones I have used don't flow much if any. Will be interested to hear your comments. Thanks for the heads up.
Hi Moray – regarding this comment-
“The first set of panels that I built and dropped into My Acoustat 0ne plus 0ne's were Kynar 28 gage wire wrap 12 wires per linear inch. They worked perfectly and sounded much better than the stock panels had.”
Is it possible to roughly quantify how much improvement can be had over stock panels? I’m running 1+1’s with X amps and the level of detail and smoothness is impressive. Do the new panels have more detail? Or apparent dynamics? And also do they behave the same with the equalization curve-or should I say - do they have the same flavor? The X amps seem more accurate than the transformers - mainly in the mid bass - maybe the EQ curve is more accurate?
One of the things I like about the Acoustat’s is their ability to not sound irritating with bad source material. They do not seem to exaggerate shrillness or hardness – it’s still there but just not emphasized. I would not want to lose that quality.
Thanks-Dave
“The first set of panels that I built and dropped into My Acoustat 0ne plus 0ne's were Kynar 28 gage wire wrap 12 wires per linear inch. They worked perfectly and sounded much better than the stock panels had.”
Is it possible to roughly quantify how much improvement can be had over stock panels? I’m running 1+1’s with X amps and the level of detail and smoothness is impressive. Do the new panels have more detail? Or apparent dynamics? And also do they behave the same with the equalization curve-or should I say - do they have the same flavor? The X amps seem more accurate than the transformers - mainly in the mid bass - maybe the EQ curve is more accurate?
One of the things I like about the Acoustat’s is their ability to not sound irritating with bad source material. They do not seem to exaggerate shrillness or hardness – it’s still there but just not emphasized. I would not want to lose that quality.
Thanks-Dave
Paul: Superior Essex has a huge line of every kind of magnet wire there is. I have not looked to see if they have an Enamel only version but worth a look. Enamel in a standard build (single coat layer) is not going to have a lot of dielectric strength so you might want to go with a heavy build.
Dave: the panels that I mentioned were identical to Acoustats except they had 12 wires per inch as opposed to the stock 6 used by Acoustat and my wires were 28 gage Kynar coated wire wrap wire. Diaphragm and felt damping were identical. These panels had more detail played a little louder and the bass was a little bit better defined or controlled. These things combined to make the panels sound a little more dynamic. I never bought stock panels again and was never interested in used ones that came up from time to time.
Taking things a step away from the Acoustat. Using thinner diaphragms will further enhance detail and extension. If there is a little more edge then it is on the recording and you will hear it but it is not hard to suffer because there is so much more information. This is not the same as turning up the treble control at all yet there will be more high frequency information but it never gets in your face. If you really like the Acoustat balance and are not looking for more detail then either build a 9 inch replacement panel with HS80 gage Mylar or build a new panel at 8 inches (outside width) and use HS65 gage Mylar. Either way will yield you a more stable diaphragm and the tone will be identical to the stock panels. The panels don't cost a lot to build so why not make some and see for yourself. The changes that I have just suggested will improve the performance of the speaker without losing the flavor balance of the stock design. I think that if you could compare two panels in which the primary difference was diaphragm thickness and you were comparing 0.65 mil (65 gage) to 0.25 mil you would not want to listen to the thicker skins any longer. Everything is better. To give you some kind of reference (and I am not referring to tonal balance but level of detail) listen to a set of Quad ESL 63's which are made with 3 micron film (about 1/8 mil thick). You will hear the speed in transients and the detail that only such thin films can achieve. So in you mind overlap those qualities onto an Acoustat and you will get an idea of where that will take you. I hope this help. I know that I did not give you what you asked for in terms of a quantified percent of difference but numbers will not tell you anything. If you change a lot more than what I have suggested then you will change the flavor balance and it will then be up to you to decide if you like the new balance or if you don't. I hope that this is of help. Regards.
Dave: the panels that I mentioned were identical to Acoustats except they had 12 wires per inch as opposed to the stock 6 used by Acoustat and my wires were 28 gage Kynar coated wire wrap wire. Diaphragm and felt damping were identical. These panels had more detail played a little louder and the bass was a little bit better defined or controlled. These things combined to make the panels sound a little more dynamic. I never bought stock panels again and was never interested in used ones that came up from time to time.
Taking things a step away from the Acoustat. Using thinner diaphragms will further enhance detail and extension. If there is a little more edge then it is on the recording and you will hear it but it is not hard to suffer because there is so much more information. This is not the same as turning up the treble control at all yet there will be more high frequency information but it never gets in your face. If you really like the Acoustat balance and are not looking for more detail then either build a 9 inch replacement panel with HS80 gage Mylar or build a new panel at 8 inches (outside width) and use HS65 gage Mylar. Either way will yield you a more stable diaphragm and the tone will be identical to the stock panels. The panels don't cost a lot to build so why not make some and see for yourself. The changes that I have just suggested will improve the performance of the speaker without losing the flavor balance of the stock design. I think that if you could compare two panels in which the primary difference was diaphragm thickness and you were comparing 0.65 mil (65 gage) to 0.25 mil you would not want to listen to the thicker skins any longer. Everything is better. To give you some kind of reference (and I am not referring to tonal balance but level of detail) listen to a set of Quad ESL 63's which are made with 3 micron film (about 1/8 mil thick). You will hear the speed in transients and the detail that only such thin films can achieve. So in you mind overlap those qualities onto an Acoustat and you will get an idea of where that will take you. I hope this help. I know that I did not give you what you asked for in terms of a quantified percent of difference but numbers will not tell you anything. If you change a lot more than what I have suggested then you will change the flavor balance and it will then be up to you to decide if you like the new balance or if you don't. I hope that this is of help. Regards.
Moray james,excellent analogy,I have found everything you had stated to be true by my own experiences and couldn't have put it in any better words as you have,as I have tried many many types of materials and thicknesses from monokote to saran.
I perfer the thinner stuff aswell.
I even have some .06mil (1/16mil) that I am dying to try,But unfortunatly I can only get it in 3" width.
I guess some sort of tweeter panel or headphone driver is in order here.
It is the same material I used to make a micro panel using old gift credit cards from x-mas.
It,s funny that I had just had that same conversation with Hella 356 last night and told him the exact same thing.
DaveG, Before I had choose to use p.c. alum. screen I was going to use kynar coated w.w. wire ,as it was the smallest gauge wire that I could find that could withstand over 10kv to 15kv without one arc thru.
I'm thinking of building a panel like my small one just to compare it to.
It would still be my wire of choice if i were to go that route today.
If you have 6000' of it by all means use it.
I feel that you would probably much more happier with the end product than you would with a breadboard rats nested with that stuff.
Trust me I have done many and it is nearly imposible to repair a mistake or make a change once it gets full.
So,I can't think of a better use for it either.
Back in 1986 that stuff was cheap compared to todays prices! jer
I perfer the thinner stuff aswell.
I even have some .06mil (1/16mil) that I am dying to try,But unfortunatly I can only get it in 3" width.
I guess some sort of tweeter panel or headphone driver is in order here.
It is the same material I used to make a micro panel using old gift credit cards from x-mas.
It,s funny that I had just had that same conversation with Hella 356 last night and told him the exact same thing.
DaveG, Before I had choose to use p.c. alum. screen I was going to use kynar coated w.w. wire ,as it was the smallest gauge wire that I could find that could withstand over 10kv to 15kv without one arc thru.
I'm thinking of building a panel like my small one just to compare it to.
It would still be my wire of choice if i were to go that route today.
If you have 6000' of it by all means use it.
I feel that you would probably much more happier with the end product than you would with a breadboard rats nested with that stuff.
Trust me I have done many and it is nearly imposible to repair a mistake or make a change once it gets full.
So,I can't think of a better use for it either.
Back in 1986 that stuff was cheap compared to todays prices! jer
Be careful with thinner membrane.
The original acoustat was 0.8 mill. If you make it thinner the design gets unstable with the same bias voltage, means the membrane will collapse into the stators. In addition your fundamental resonance will drop, certainly in direction 20 Hz. This makes no sense, it means a lot of excursion required and nothing to hear !
If you use thinner mylar, you should add silicone dots.
Capaciti
The original acoustat was 0.8 mill. If you make it thinner the design gets unstable with the same bias voltage, means the membrane will collapse into the stators. In addition your fundamental resonance will drop, certainly in direction 20 Hz. This makes no sense, it means a lot of excursion required and nothing to hear !
If you use thinner mylar, you should add silicone dots.
Capaciti