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All right, here it is as promised, my trials and tribulations of re-coiling the "beast". In this case, a pair os SMGa loudspeakers.
Be warned, it's long. Hopefully that means all the questions are answered.
Chapter One - What's the Buzz?
You hear a buzz, you hear a rattle. Not always, but always on the same passage, always in the same place. What does it mean? It means the coils on your maggies are coming unglued. Why? Because the two products used to adhere them went bad. The first being 3M 77 spray adhesive, the second a liquid water based pvc called Milloxane. The former is just supposed to hold the coils in place while the latter is applied and cures, and aye, there's the rub.
I know as a woodworker, if I want to bond 2 surfaces, I PUT THE GLUE BETWEEN THEM. What magnepan does, is use a tacky substrate, and then hopes a liquid blanket is going to hold the coils down. Oh it does, but not forever, certainly not forever... I think it is fair to say every maggie 20 years or older has, had, or soon will have coils coming off. A fair number even start losing them in 10 years or less. For this I blame the proceedure, and the use of a product in a job it CANNOT do.
Why I HATE 3M 77 spray adhesive
I am not a conspiracy sort, and I am sure the reason Jim Winey used 3m 77 is because it was handy because he worked for 3m at the time and they made it. I am sure they continue to use it because magnepan makes changes like watching catci grow. They both look different after 10 years but you never really saw it happen.....
However my experiences with this product have caused me to not only think little of it's qualities, I revile it. And I don't mean the way liberals hate Bush but don't know why or right wing nuts blow up abortion clinics because life is so precious, no, I mean the kind of hate a man reserves for a thing that lets him down so repeatedly (a car is a good example) that all he can do is go out and unload a magazine of rounds into it. That act is the only thing preserving his sanity.
IMHO, 3M 77 is a vaudvillian product. By that I mean it harbours all the qualities of a Three Stooges or WC Fields stage prop. It will NOT glue the things you want glued, at least not in the long term, but it WILL glue every thing else it comes in contact with with a tenacity that is unparalleled. I have tried it in countless applications, all acts fully supported by the label and in a manner of application described on the can, and EVERY time it has either immediately or in the short long term, failed.
And lets be honest, this is the thing really holding the coils down, because when it stops, the milloxane can't do it, and I have proof. So let us begin.
Chapter Two - The Problem Revealed
Here is what the culprit usually looks like:
They do let loose in the middle, but this is the more common ailment, the ends peeling up like a bananna. Amazingly too, they'll make less noise like this than the loose wire mid panel will. The "person" I bought these from was in fact sure that they played just fine. You can check them in person by feeling the backs lightly with your hand wiping from the inside to the edge of the panel. If they are raised, you'll feel it.
To get to the point pictured above, you'll first need to remove the side wood trim which is easy enough. Then lie the panels down on their faces (which is the magnet side and always the preffered face to be down) and remove the jillion staples holding the socks on. (this is the hardest part of the whole business actually) You'll find 2 layers, and about 75 staples on each. If magnepan was only this anal about the capacitors going into these things....
Then unscrew the back terminal plate. With the speaker still flat start removing the sock, but be very careful because if your lower coils are coming off, taking the fabric off will go against their "lie" and will pull at them, ripping them off further. Pull the fabric up high and away from them until you are past them. You can then stand the speaker up and take the sock off the rest of the way easily, but watch out, there may be more staples at the top sides.
Chapter Three - The Fix
Now it's time to clean the old adhesive off. I cannot be positive, but I have noticed 2 kinds of aging. It seems in dry hot areas, the adhesive gets amber colored and brittle. In more humid areas, or especially near the ocean, it turns green and gets gummy. Mine came from Brooklyn, so they were green and gummy. I do not know if the adhesive comes off easier or harder in the amber state.
You will need a can of acetone, large cotton puffs or other natural wipe, and Q tips. Years ago in the shop I used a man made sponge only to find the minute it hit the acetone a reaction occurred and the sponge got hard as a brick. Whatever wipe you use can't be man made.
The picture below shows my method of dealing with it.
The green line shows the point the wires are loose to. I cleaned a little past that point (the blue lines) to insure the problem didn't re-occur in a year. Pour some acetone in a small bowl, and dip your pad into it. Squeeze it out so it does not run, but is generally wet and apply it to the point in purple above and stroke with the wire towards the outside of the panel. I go down short of the blue line because it will spread out that far on it's own when you press.
Do one coil at a time, turning the wipe as crud builds up on it, and discarding it when fully loaded. To clean the wires themselves put a finger under them and drag the wipe over them pulling both fingers along. The glue should come off in very little time.
Then bend back the coils to about the angle shown in the pic below by holding a finger at the lose point and lifting them. (if a double loop be carefull to get both) You can then dip Q tips in the acetone to get to the very narrowest undersides and places you couldn't wipe. Sometimes you get a ball of crud going but it won't pick up. Just flip the Q tip and grab it with the dry side, that usually gets it, then wipe the spot it was at again with the wet side.
When done, it should look like this. Squeeky clean and no more green.
You may notice the tips of the tweeters are green, but they were really down fast and working fine, so I let well enough alone.
Chapter Four - A New Horror
This is when things started getting ugly. Once dry, I applied the RECOMMENDED amount of 3m 77 spray adhesive to the panels. I allowed it to tack up, and then carefully pressed the coils back in place. (in place is between the magnets on the other side. You'll see the space line, and the wire should go down the middle between the rows)
I let them go for a good while, and then came back and applied the milloxane. (with a wide artists brush, not the one in the damn can) That's when the funny thing happened. Milloxane is water based like elmers glue, only it sets up rubbery not hard. It's purpose is to make a rear ersatz panel over the coils. Well, the 3m decided not to have any part of this, and let loose. Since the milloxane can't hold a rising coil alone, they rose, and took the milloxane with it.
I had to re strip it all over again. This time I applied even more 3m. Same result. I stripped it AGAIN and applied less 3m. SAME result. Threw 3m in the trash and swore loudly and vigorously. Same result, but I felt better. At this point I am not interested in hearing from engineers. YES, I read the can, YES I followed instructions, YES the room was 70 degrees, YES the can was new. THE PRODUCT JUST SUCKS. It's that simple.
Chapter Five - 10 Novenas and Call me In The Morning
Worrying. That was my next step. So I then ran to the archives and began to see I'm not the only one apparently. People were making elaborate jigs out of aluminum or buying heaters to attach to the speaker terminals to heat the coils until they lied flat etc...
Well F*CK that. I will be damned if I am going to go to an extreme like that to make up for the shortcomings of a product that does not work. I'll find a product that does work instead. So after a little thought only one thing came to mind.
Yes, DAP Weldwood contact cement. It is also acetone based, but unlike 3m 77 , it WORKS. I have used it in the past to adhere veneer, and it never comes off, EVER. Wet part A, wet part B, attach parts, you now have part C because you are never getting them apart again. This little bottle cost $2.65 compared to nearly ten bucks for the 3m.
There is required care in it's use however, which I will explain.
So I returned to a newly stripped panel to try my luck again. For apllication purposes I used 2 sizes of artist brushes, NOT again the one that comes in the bottle. In fact, I cut that one entirely off to facilitate ease of use and recommend you do likewise.
I used the fatter blue brush (1/4 inch wide) to first apply adhesive to the undersides of the wires. I shortly found the glue was already curing and getting a little stringy out of the bottle. The trick is to keep dipping the brush in acetone as you work. From time to time you also have to stop and clean the buildup that happens. (be careful doing this. Acetone dissolves the glue holding the bristles in the brush, so be careful not to pull at them or you will pull them right out) I did 2 or 3 wire rows, and then did the corresponding part of the panel. For the mylar I got the brush good and soaked in the acteone first, then got a good glob of adhesive and wiped it on with the "grain". When getting to where the coil touches the mylar, allow the brush to run under as far as it can.
I would then go and do the next 2 coils, allowing the adhesive I'd applied to set. Then, I pressed the coils back to the mylar in line with the magnets as explained before. To do this I took a clothespin apart and used the flat bottom edge as a pressing guide. Repeat until the panel is done.
I let it dry a few hours then put the milloxane on. To my surprise it again lifted, but only at like 2 places and only very slightly at the very tips. Water based items don't dissolve acetone based ones, but perhaps even more time curing might help. I only needed use the fine brush above to re wet the tips with the DAP and press them back down. They have since held fine and the result is much cleaner looking and less grungy than the 3m job was.
Chapter Six - Bench Test
The next step is to hook them up and listen, a good long while to various buzz causing pieces of music. You'll notice top left in the pic, the ceiling wallpaper came off. That's right, the 3m 77 adhesive I put them up with ISN'T HOLDING. I have to redo the ENTIRE ceiling. That's no surprise, it didn't hold the blue tiles on either. I had already redone them with liquid nails. It didn't hold the grey ones on the side wall either, ditto. Well, we know it won't hold maggie voice coils on as well, so what's the shock?
In a short while it was clear the repair job was a complete success, but I did have rattles amid panel. Play the selection that makes them rattle and go stand behind them and listen. You'll be able to hear and "see" exactly where it is coming from, but be careful and DO NOT touch the wires while they are playing. Remember or write down the locations, unhook them, and back to the work table.
While flat, lightly brush your hand across the wires where you heard the buzz like you're playing a harp. You'll soon find the loose ones. My solution was to take the fine brush again, dip it in the DAP and carefully ride it under the wire, being careful to get both the wire and the mylar covered. No, I did not strip on this step, I was just slightly heavier with the DAP. Let it set up, and press back down.
After curing again I hooked them up for more testing. I've put about 10 hours in and not a buzz, and they sound great. Be careful you don't use Ivy's "Hideaway". My wife wanted to hear it and there is an odd buzz sound in it that when your ears are perked for maggie buzzing makes you think it's them. I swapped the Alons in and heard the same thing so it was just the song.
Chapter Seven - Moral and Conclusion
I do not doubt some chemist will reply and say I could have ruined the mylar using the DAP or god knows what. If the gushes or acteone don't harm the mylar, the DAP sure as hell won't. Plus it is designed to be used on wood which moves (seasonal expansion and contraction) and not come apart, so clearly it does not dry hard and is not effected by, nor does it effect, movement.
Used judiciously it can be applied very lightly yet it holds so strongly I honestly believe no milloxane is afterwards needed. I used the milloaxe afterwards because I had it, but I know many people realize they need to redo maggies in october only to find magnepan is no longer shipping it. (because it freezes in the mail being water based and that ruins it) So, who wants to wait till May with buzzing maggies? Not me.
I believe you can use the DAP and solve your problem right here and now. If you are the worrying type, order the milloxane next year and put it on as well, but I think the DAP does the job. It actually bound the wire to the mylar, so it doesn't need the plastic milloxane coat to hold it there. Of course time and further experimentation will tell. So far my results have been very good.
Thank you for getting thru it all, and I hope this will be of some help to the loyal suffering maggie owners out there. Set yourself free from 3m and milloxane, and enjoy your music again.
And now the next step, the parts upgrade....
Firstly congratulations to Peter for a brilliant post - great photos, clear explanations. I was going to send in something similar about my experiences with my SMGa repair, but frankly Peter's said most of what I wanted to say.
All I would add is that my experiences with 3M77 were not as bad, probably because of two factors. Bending the wires up does indeed improve accessibility to the underside of the wire and the mylar, but once the wire is bent past its elastic limit it "kinks" and thereafter will exert a permanent upward force against the glue while it dries. I tried very hard to avoid doing this although suffered horribly from the 3M77 "sticks to everything" syndrome. Secondly I left the 3M77 to dry for a couple of days before applying the milloxane - by this time it had cured to an inert layer and did not seem to react to the milloxane.
I believe that SMG's pre-date milloxane completely - and mine certainly looked as though it had never been treated. As well as acting as a glue (and I take Peter's point about applying as a blanket over the top is never going to be as efficient as gluing drectly between the two surfaces) it is also supposed to act as a UV filter, since UV light over time will degrade the 3M77 or glues of this type. Thus I would say that it's always worth applying the milloxane. I too used a wide artist's brush and treated the whole panel, woofer and tweeter - it takes a fair while to do this (at least an hour each coat) and needs two coats, both panels.
I let it dry for a week - and there my saga comes to an end (or at least a pause). I too am upgrading the crossover and (perhaps foolishly) stripped down the old crossovers at the same time. At the time of writing the panels are in my garage waiting for when I get some free time (3 kids and MGIIIa's to take up my leisure time)to construct new housings and the XO and reassemble the speakers.
So don't know how they will sound, but the wires certainly seem to be securely and neatly attached throughout.
The report I got from Jim was that when the US banned freon, 3M switched to a propellant in the 3M spray which contains butane, a solvent for contact cement. The old procedure was to spray the 77 cement, lay the wires down and then brush another coat of contact cement over the wires. This worked unless the 77 was not fully cured and then the butane would dissolve the contact cement bond. It took several years for Magnepan to figure this out because they had cases of the older freon stuff in their lab and could not dupliucate the results in the field, and, of course, 3M did not tell them that the propellant had butane in it. They switched to the Miloxane in the interim hoping to cure the problem.
Their current 'quasi ribbon' is a sandwich of mylar and a foil voice coil and solves the problem but their bass panels still employ the glue and wire.
My procedure differs from yours in after cleaning the panels I hold down the wires with a steel rod, although an allen wrench set works well also. The magnets will keep the steel in place. I then take a small 1" brush and literally paint bulk contact cement (I use a 3M industrial product) unto the wires: a thin coat first to make sure that the wire is attached, and then after the first coat has dried, I follow with a thicker coat (of course, after removing the steel hold downs). The procedure works well and I rarely have problems following.
I would add that you ought to clean any corrosion spots you see and reseal the area with contact cement.
Of course this is a forum for airing our grievances and expressing our desires, but like petulant children we often forget we have never walked a foot, let alone a mile in Mr. Wineys shoes.
Like all things we should perhaps expect less, and magnepan could perhaps do a little more, but in the end we should be thankful that the things exist at all and that we are here to enjoy them.
I know for a fact that Jim Winey and his son were deeply troubled by the failure of their panels and were desperately seeking a cure. I used to work for a Magnepan dealer for the first half of the '80's, and it was utterly frustrating for us, too, and we went through hell in doing repair after repair.
One of the most frustrating things about Magnepan is that their marketing manager does NOT encourage tweaking. In fact when we experimented with running double Pans, he threatened to cut us off if we ever demoed the double Pan system. He blew his stack when I once commented that the Pans benefited from drilling and tapping the stands for a set of spiked feet. I believe he would like Magnepan to be like Bose in the industry.....
The double Pan system if you are curious consisted in running a second pair of Maggies, (a smaller model would do) alongside the front mains. You would position the mains as you normally would,but then would angle the side speakers to fire outboard. Imagine a sort of flat 'W' formation with a gap in the middle when viewed from the top. The result was significantly more bass, and a 3D imaging like you wouldn't believe. I believe we kept the tweeter inboard on the front firing pair and the tweeters ouboard on the outboard pair.
The result was a sort of pocket behind the panels where the presentation sounded like a group was sitting and performing. If you ever get a second pair of 'Pans, you ought to try it.
Once again nice post. I agree when it comes to the coil bends 3M has it's work cut out for it (although I've used it w/o incident and still standing strong after 2 yrs-[knock on mylar])
However, I can't help but wonder if certain adhesives (certainly the most potent ones) won't 'eat' through or even 'melt' that fragile mylar after prolonged use. One would think water based adhesives maintains a better threshold when dealing with vibrating (thus heat generating) coils vs pertroleum based glues.
Not knockin' your selection, just thinkin' out loud-
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The part that "eats" and "melts" is the carrier, and the most aggressive of the carriers is acetone. It is in the DAP and the 3m 77. It does not effect the mylar unless you were to expose it for a severe length of time. Otherwise, being as volatile as it is it evaporates almost instantly. (the only thing more volatile I know of is Last record preservative) And there is more of it hitting the mylar during cleaning than when re ataching the coils.
In any case, when it's gone, that's it. And it's gone nearly immediately.
Also, acetone is not petroleum based. It is manufactured but it also occurs naturally in nature in plants and trees as well as other sources. So it also mixes with water, unlike petroleum products, but the materials it carries generally are not soluable in water, which is an irony.
DAP has long been used as a veneer glue, and many woods have tannic and other acids that would react with a caustic carrier and darken or effect such a thin strip of wood. DAP does not do this, and it also does not get brittle as it is not effected by the movement of wood expansion and contraction. That's why I chose it.
There was also a reply early in the post who said he'd been using the DAP for years on electrostats with great success (yeah, thanks for keeeping it a secret :^ ) with no side effects. He is just starting to try the water based type, but he too is wary of it's longevity, especially in humid conditions.
I've been rocking them a good 4-5 hours a night since I did it and they are working and sounding great. Teamed to the other persons comments about using it for years with stats, I think we have a worry free done deal.
Ding Dong, it's the death knell for 3M 77.
This may be really stupid but couldn't Magnepan come up with a process that imbeds the wire in the mylar as opposed to gluing. The molded wire/mylar could be pre-fabed in different lengths for the different models and there would never be any wire buzz problems....ever.
Imbedding the wire in the film would be virtually impossible. If one could come up with a method it would most likely have to be done at the film mfgr. end which would make the cost of the film/mylar/wire skyrocket. I could see a price point of $50-70K easily for a Maggie. If such a thing could even be done. I just don't see this as practical for any company let alone a company as small as Magnepan.
I have had custom mylar produced by DuPont. It is expensive to say the least. Something like imbedding the wire would be way past Magnepan's engineering or manufacutring prowess I imagine. DuPont or some similiar supplier would have to develop the process. The price tag would blow one's mind!
About the closest one might see is the Maggie QR type tweeter, or Infinity EMIT/EMIM and other such approaches. Instead of glueing a small diamter wire to the film, which has an extremely small contact area, the wire is 'flat'. Much more contact area with the film, hence better long-term adhesion.
I am not aware of what agony goes into making mylar, but I was not thinking of "imbedding", which implies making the mylar with the wire in it. I was talking of pressing 2 made sheets together with the coil between them.
Or is this not possible? Is mylar one of those things that cannot be made to adhere to anything, even itself, after it is made?
OK, what about this. What if you had 2 sheets firmly held in the speaker frame, the coils laid between them, and all 4 sides have been "sealed" (like by a bag sealer method if possibe, so it is now like a plastic bag) except for a miniscule pinhole attached to a compressor that is used to suck the air out. This causes the mylar to go drum tight on the coils (and itself), and then the pinhole is sealed.
Of course if it ever got punctured, game over.
Well, it's all talk at this juncture anyway, but I'll let magnepan slide on this issue then :^ ) But they still ought to replace the 3m77 with something else.
No stuff will stick to mylar. Just not the 3M spray!
I understand your idea better. This would be tough but potentially could be done.
One must keep in mind that Magnepan has choosen a path of economy. Could they be done better? Absolutely, but at a price. For instance, a true push-pull driver is much better, but you can't do something like that at the SMG price point.
Many products, including the Maggies could be made much better. But then price goes up. I believe Magnepan has struck the correct balance of performance vs. price. This is of course a matter of debate!
One thing for sure, prices would be much higher on the product if Magnepan implemented some of the ideas we hear on this board, most of which are excellent. And then they may not be quite as appealing given the competition. Would not sell as many, more price increases, etc. It is always a tough balancing act. Magnepan's longetivity and reputation in the market place shows their choses have served both Magnepan and the legions of happy customers quite well IMO.
The things are great stock and can be improved upon greatly. But most Maggies never get touched. When I had them I never thought of making any mods. I was thrilled with them as is. I imagine that situation would be different if them owned them today.
"Dissing" Magnepan on here is akin to the problems I encounter reviewing music in the indie world. The majors have so beaten it down that everyone feels every review should be a good one, or nobdy will buy it, etc... so it is very taboo.
My feeling is, if you tell them shit is shinola they sure as hell won't buy shinola again. I LOVE maggies, they are the only speakers I have ever loved, but they have problems, and so does the company.
In that vein, I think magnepan, or perhaps more pointedly Mr. Winey, reminds me a lot of the Wright Brothers. They both did some groundwork and suddenly found they invented something nobody else ever had. And the first thing both of them did was run to the patent office and secure every step so nobody else could ever make one.
It's theirs, they made it, period. You try to make one, see you in court.
Both of them also seemed to suffer from the belief that both were nearly perfect to begin with. Once the Wrights info got out, people like Glenn Curtiss were making planes that could fly rings around the Wrights, who were too busy suing everyone. It's very telling that we invented the airplane, yet in WWI we were the only country that could not make it's own front line fighter plane. We had none, because of the Wrights.
I think if magnepan had leased it's patents to say 3-5 other companies back in 1990, you would see planer designs that would boggle the mind and ears by now. But they didn't, and they won't, even though the royalties would more than make up for any lost sales. It's the Wright mentality, best illustrated in an old cartoon from the time with Orville looking up at a plane and shouting "Get out of my sky!".
They only make miniscule changes every 10 years, they don't correct flawed processes (I am sure someone could design a machine that could hot wrap the coils between 2 sheets of ultra thin mylar which would resolve this problem forever, and it would not kill them to build with better caps and coils upon request) and while their customer service is good, they don't even have a presence on a board like this.
And what can you do? They have a monopoly, the old their way or the highway. I would like to see them embrace their speakers with the passion we all do, but they don't, and I don't see that changing.
I agree whole-heartily on your take with Magnepan not chosing to license their technology. Mr Winey himself stated in a interview how his battle with Apogee had taken a toll on himself and his company.
Add him to the ranks of the Wrights, the Jobs, the Wozniaks, etc.,
This also gives me a chance to toot my horn in regards to the Wright bros. Having been raised in the same home town (Dayton,OH) they're truly an American legend. Every self respecting Daytonian gags each time we see a license plate from North Carolina that states "first in flight"- not so! MANY test flights occured in Dayton long before they chose the windy shores of NC for that historic first flight. In fact, the area they did most of their testing is now sacred ground dead smack in the middle of Wright-Patterson Air Force base in Dayton overlooking F16's, stealth bombers and other SOTA aircraft now land.
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Yes, as much as I, and all of us love Maggies there are a TON of things they could do different... or better at the factory. I'm not even gonna start the list, like I said this could be a whole 'nother thread, hats off to Peter for speaking his mind and bringing up the subject.
I like your idea too, about letting the patents loose for other's interpretation of the Magneplanar speaker topology, but then again I find it kind of cool that Magnepan is the "only one" of it's kind and to own them is special and unique. Sure, there were a few other companies that had similar designs- Polyplanar is one a long time ago, but not quite the real deal. Don't know exactly how their designs were, but they must have been just different enough to not warrant any recourse sent their way.
And of course, there are many, many things abouut Maggies that I would not change a bit if I had the chance. Quite a few factors on improvement would be model- specific, having to adhere to the performance/ price ratio, and in this area, Magnepan accels like no other. I think we would all agree on one area that needs improvement... general build quality. I'm not talking a complete makeover, not a massive re-designed platform, just some changes and tweaks here and there, and some NEW ideas. Jim still designs each and every model, and has done an excellent job on every one of them (not to mention inventing the technology!) but there comes a time to evolve a bit.
And I'm not usually thanked for it....... :^ )
I can appreciate the uniqueness. It's the largest selling high end speaker of all time, yet nobody in the general public knows what it is, even when they see one. But it's due to zealots like us who show them to friends, family, or hell, anyone who's interested! Magnepan sales come from word of mouth principly, and the mouth is ours. I suppose that's why we feel they "owe" us. :^ )
But I'm not talking about letting it all go, just a license to a few select companies with the background, resources or good ideas to make the most of them.
And imagine if the poor long suffering europeans could have a maggie factory in Germany? The Lord wouldn't have had to come here, and they can call them BMW's (Bayerin Magnepanishe Werke)
Then snobs here can buy them, brag that they're better than US maggies, and Mart can chew them a new cornchute. Imagine the fun!
Perhaps I was tough on magnepan, but I'd just like to see obvious problems addressed (do they not have enough real work to do that they can waste time repairing bad coils, or is that part of the profit scheme?) and it would be nice to see them offer auidophile grade versions of the 1 and 3 series. (better caps, coils, wiring, terminals etc...)
I cannot see how the latter could possibly be a problem or cost them money. In fact, I wonder how much business they lose because people would have bought a tweaked 3.6 but are afraid or incapable of doing it themselves so they buy some pricier speaker instead.
Ahhh, like all lifes mysteries, we'll never know...
I remain amazed how much Rutan's most "inventive" planes have more than a vague resemblance to that original plane, at the very least ... more so than rationality dictates that it has any right too. I remain impressed! They certainly optimized the lift to thrust ratio, but then again they had to with those POS engines running on crappy fuel.
That's where I believe the analogy ends. Magnepan has access to excellent motors. It's one of those issues that makes one's head itch. OK, maybe I wouldn't expect ceramic magnets on its more affordable stuff, by why not their flagship? I realize that too already blasts its competition at its price point, but I can't help but wonder how many hassles could be solved via stronger motors. Hell, with reduced current, one can use thinner gauged wires for lighter moving mass at higher amplifier-friendly impedances, at much improved efficiencies.
♪ moderate Mart £ ♫
that stronger motors made of different magnets would sound OK.
Keep in mind that the magnetic fields from the wires cause eddy currents in nearby conductors, which include the magnets if they are metal alloy. Any change to the conductivity or conductance of the magnet structure might be audible.
IIRC, the strong rare earth magnets have measurably less ability to eddy current. That's a difference all right, but that one seems superficially counter intuitive. Don't get me wrong, I'm not doubting you. This one stump is just gonna stump me for a while.
♪ moderate Mart £ ♫
The magnet material has an effective permeability to external fields as well as an effective conductivity. The source of the external field is moving with respect to the magnet. My head hurts!
That was a great step-by-step 'saga'. I think that even I could use your technique and succeed, and I can't build a bookshelf.
Being in the telecom world, I have to attend hundreds of hours of training by vendors, and if only they had your teaching skills!
Great post; outstanding teaching tool.
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Why do the wires like to curl up at the ends. To me no longer adhering is one thing... but it is pretty clear it is not like they fall off as a "straight sheet" (if you get my point.. not enough sleep and I do not even make sense to myself these days :-).
Is there some kind of stress relief (I am an idiot here) that could be done so that the ends do not try to pull away?
IMHO, I think it's purely mechanical. If you make a hank from a rope or an electric cord you have to put a small twist with each loop in order for the loops to lie flat. When Magnepan lays the wire down on the mylar the wire is not twisted at the bend and this creates stress at that point making the ends pop up.
The Lorenz forces are way too weak. However, my theory is theraml cycling. The U-turn end, by the permanent deformation during manufacture, raises the local resistivity. That's why you never see kinked wires not being crimped and/or soldered. This can be a thermal instability. You see, seeing that these local resistivities are small compared to the overall length, any local increase in resistivity doesn't appreciably change the VC's impedance at all. Thus, the current doesn't change, but the local I²×R heating certainly does. I haven't quite determined if pulling away from the thermal insulating Mylar to a lower (cooler) energy state was sufficient to make the bends "banana", or whether the constant maleting by the excurting Mylar significantly helped while the coil is warm. Once delamination starts, the reciprocating Mylar is only pounding in one direction. The only issue is then initiation. There's no doubt that the U-turns have the greatest delaminating tensile force. As the Mylar excurts away from the magnets, it wants to bow, while the VC wants to keep the area it occupies flat. At the tops & bottoms of the VC, the greatest tensile force is distributed at the appex of the U-turns (over the least contact area). As the Mylar excurts toward the magnets, the delaminated pair re-contacts. Now, repeat several trillons of times over a decade...
♪ moderate Mart £ ♫
I think it is because in the middle the surface tension of everything around you keeps you stuck. On the edge, you have a side where the surface tension ends, which allows for failure as it's the one weak spot. Stickers never peel from the middle either.
As to why they bend, once a wire comes off it is going to move when the speaker plays. At the point where the separation occurs the topside of the wire is under compression, while the underside of the wire by the mylar is getting stretched ever so slightly as the vibrations try to pull it away.
So as more and more comes off, it will have a slight bent put in it from this compression and stretching, which even defies gravity as coils on the bottom bend upwards as well.
At least that would be my guess.
As to why they come off, IMHO it happens because 3M 77 sucks eggs. If you use a REAL adhesive, a mans adhesive mind you, I think that will resolve the issue for good and the ends no longer will be able to pull away.
As far as I know as well, the DAP does not deteriorate over time like the 3m and milloxane apparently do. I know old timers who have used it to veneer with never a failure.
Thanks for a great attitude!
Looking forward to reading your adventures in tweaking the crossovers.
When putting on the DAP, you can't be a slob, but you also can't overly worry.
Even done right, it will look like it's going to be ugly, or dark etc... but if you use care it will turn out OK.
The trick in applying it to the wires is to keep the brush wet by cleaning it after every 2-3 coils with acetone, and to apply a "nice" amount. A "nice" amount is putting the brush in just up to the ferrule and pulling it straight out of the DAP. Don't try to "dig" more. Then apply per the diagram below by not only moving the brush, but slightly turning it as you go to prevent globs. If you just move the brush it will act like a plow and will glob glue in front of it. On top of it the DAP will naturally hang from the brush. That's why you must spin it as you go.
You also don't want to start where the coil and mylar are in contact because it will glob there and you can't get under to make sure it is coated. Starting a bit below halfway, and going to the tip first seemed to work best for me.
Now, of course you don't have to follow my pattern, but you should keep in mind to turn the brush, make sure the tip gets done well, and get as far under the wires where they join the myalr without clumping it. And keep cleaning the brush as you go.
When you do the mylar have the brush much wetter, but also grab more glue, and apply it with quick, long strokes.
In all cases, even if it looks bad, DON'T RE-DO IT. This product does not want to re-apply over itself. Trust me, what you did will work, and it will also look better once it dries and cures.
Doing one side of a panel only took about 15 minutes. It's only marginally anal retentive, and it's over very quickly actually.
Why didn't you post this two weeks ago? I had gotten totally frustrated with 3M 77 failures on my MGIIIa's and sent them to Magnepan for a professional regluing. Estimated cost of repair including return shipping is $280.00. My experience with 3M 77 was exactly like yours.
Interestingly when I repaired a set of IIb's several years ago (completely replacing the tweeter wires), the repair went really smooth.
I guess once the wires take a curl away from the mylar they don't want to come back.
Excellent post. Mart - Please post this in the tweak section of the forum.
Did you ever think about some Apogees...just asking :). BTW nice looking system, I bet the Hovland and Pass give a great sound.
Not meaning to step on toes here, but any Scintilla played many years ago probably was mishandled. The amps didn't exist that could go peacefully with them, except, perhaps the biggest Jadis. My hearing, too, has been tested off the charts. I had to pass up all the live rock and roll events, because of the pain the screeching guitars induced.
I just got back from New York, where I saw, "Dirty Rotten Scoundrels," on Broadway. The House generously gave everyone CDs of the show. When I got home, I popped the CD into my Scintilla system, and brought the show into my listening room.
Thanks to my great new era amps, and the other simple circuit components, my Scintillas can do any genre.
I only heard them once, but as I just posted recently on some other topic, I have acute high end hearing and I cannot abide any metalic ribbon drivers. They tear right thru me, and will forever be a pleasure I am denied.
It took a lot of work to get there surprisingly, but yes, the Hovland and Pass seem to like each other and accentuate each others qualities well.
If I could only finish everything!
Well actually many of the Apogees (like Caliper Sig, Duetta Sig, Stage, Studio grand) don't have a true metal ribbon tweeter. It is actually a plastic (kapton) ribbon with three (or six in the later models)aluminum strips glued on to make the motor. Unlike the Maggie true ribbon, which I think can sound quite metallic with certain sounds or levels, there is not a hint of metallic coloration in these ribbons. You are likely thinking of the Scintilla, Diva, or Full Range when thinking about pure metal ribbons in Apogees. My girlfriend is also extremely sensitive to this coloration (My IRS Betas also had that metallic flavor in the highs and she hated them even though everything else was nearly perfect) and she has no problems with my Caliper Signatures (in fact she rather loves them). If you have not heard the versions with this type of midrange/tweeter then you really should as the sound is really world class (especially with regard to coherence).
It has been a while and I don't remember but I am pretty sure it was the Scintilla I heard.
You are probably correct in your assessment of my liking the others then, but what I find amusing is the root of the notion that we are all whores looking for the next better, bigger "more perfect" sound.
We all find people who are perfectly happy and tell them about gear they didn't know about to upset their apple carts and put them back on the upgrade cycle, as if letting well enough alone is not acceptable :^ )
I had heard lots of praise for the Duetta Sigs but had ignored the info thinking they were metal ribbons. Now that bee is in my bonnet, thanks.
I had not finalized an option for speakers until the room was done and I knew a large planer would work up there. Now that I know they will, all options are on the table. My ideal was the Soundlab M3's (I can't fit anything taller in the room because of the cross beams) but I have not heard a pair yet. If they don't work out all options are open, including the apogees now I suppose.
Thanks a lot, I think :^ )
Sorry didn't mean to excite your obssessive/complusive behavior :). However, I would consider those Soundlabs also,MMMM soundlabs (too big for my space...and my wallet.)
Here's another approch that has worked very well for me on 3 separate occasions. After the 3m 77 has tacked up (about 20-25 mins.), working quickly, press the wires down, you may need to go back and forth to the ones pressed down first as they try to begin to re-lift. When all are in place, quickly secure them down with a single piece of electrical tape spanning the entire width of the panel so that the tape just barely covers the wires at the point where they bend around. Secure the ends of the tape well out onto the MDF. Now you can lay a weight on top of the tape to hold the wires down securly.Wait about an hour for the 3m to hold securly, and remove the weight. Now apply the moloxaine over the wires and the electrical tape as well, this will form a single high strength unit that will never come loose again. There is almost no movement and no sound produced at the extreem end of the mylar where the wires end, so the tape will have no sonic effect. I have three pairs that I have repaired this way going back over 7 years and have had no further problem with wires lifting at the ends. Good luck and happy listening. Tony
Hearty congratulations for making it work, but I do not think I could or would recommend your proceedure to anyone else. I also know electrical tape can go bad and dry out over time and if it does, then the panels might be damaged or put beyond re-repair.
I would also not discount that you might have lost some resolution stiffening the ends like that. They are not the most vocal parts of the panel it is true, but boy, does that sound like a "field" repair.
In the final analysis, it is easier and better to wipe on some DAP and be done, than to go thru the machinations you did and hope for the best.
That said, I hope you never have a problem.
You are a very determined audiophile to be sure! When my ten year old MG-1.5s delaminated a few years ago, I elected to have Magnepan rebuild the speakers rather than attempt it myself. The end result was a speaker that sounded identical to new for about $325. Rebuilding an SMG makes less sense given the availability of the MMG, but should return the speaker to "like-new" condition. Updating or repairing conventional loudspeakers is either impossible (drivers unavailable) or quite expensive. It is a tribute to Magnepan that they continue to provide support for speakers made decades ago at a reasonable cost.
My conclusion after the fact is that the 3m is the hell step, and that is magnepans hell, and one you needn't go thru.
The fact is, wiping off the glue with acetone is easy, brushing on DAP is easy, the wires will then stick to the mylar, AND FOR GOOD, and you don't even need the milloxane step.
So it's a $6 can of acetone (you need very little) and $2.65 for the DAP. $8.65 beats the heck out of $325 and with all the worn out MGI's out there that need this, there is no reason to fear it or not fix them, and one entirely takes UPS out of the loop which HAS to be a good thing. Ten bucks and one afternoon and you're rocking by midnight again.
It is a tribute and a shame. They should fix the old failures, and they do, but they also should stop using products to adhere the coils that time has proven are faulty. I could get a brand new pair of 1.6's, and it isn't if they'll fail but when. That's just wrong.
For the record I did not get these to do this to, I bought them to experiment doing crossover mods. That they needed this done was a surprise to me when I got them home, but again, I only paid around $100 for them too, and I picked them up.
Thanks for the reply.
Thanks for the great post, Peter! I've been dreading regluing my IIIA's after some of the horror stories I've heard very similar to yours. I use DAP contact cement all the time so it will be a pleasure to use it knowing it will work in one step. Do you really think the Miloxane is necessary after the DAP?
BTW, I miss your 5 gallon joint cement buckets in your system. How does the room sound without their diffusing qualities? :-)
...and that is a whole 'nother saga as well. I built my own shelf to see if it was better than the target shelf. Yes and no. I am eventually going to try to hybridize the Target shelf and if it works gets 2 more and do them as well.
But getting the Hovland off of the buckets and on a steady footing made worlds of difference. As I said before, buckets are NOT a recommended tweak :^ )
Magnepan uses the milloxane because obviously the 3m does not work. The DAP however does, so it is my guess that if you fix a buzz with the DAP you can forego the milloxane.
So get those socks off and get to it. Just don't drop your brush in the acetone like I did. That's why the one is now wood, it used to be blue too.... but on the flip side I have a nice blue can of acetone....
Definitely one for the archives! Great post sir, very informative.
With this as reference , it will save a lot of headaches for those who will refurb/cure their buzzing maggies in the future (hope it's not my turn yet....knock on wood)!
Great article, I only wish it were up several months ago when I did my MG-Is. Fortunately, my wires weren't near so bent up as yours, but I had to redo a tweeter at the same time. For some odd reason, the 3M actually worked with that ultra-fine wire, but for the rest I was inventing new curse words to describe it. My haphazard solution for the big wires was to weigh the ends down with sockets, two sets worth in fact, while rotating them occassionally to minimize their being glued to the Maggies. Very frustrating.
I should warn you that it may be a long time, if ever, before you can get socks back on those. Everytime over the last several months (the better part of a year, in fact) that I've started to make motions to put the socks back on, some new rattle appears midpanel that I have to touch up with the Miloxane to settle out. At the rate I'm going at, I'm going to have the entire panel redone before I can finally gussy them up again and make pretty in new clothes.
I share your loathing for 3M adhesives. They work about as well as Microsoft software.
The price stickers designed to be destroyed upon removal are especially troublesome. A little cooking oil softens the remaining adhesive, but what do you do if the product is made of cardboard?
Glad you liked the post.
I wouldn't say my hands are like iron but they are reasonably tough from my profession. That said, I tried a latex glove at first when doing this but the acetone soon started destroying it and I didn't want residue from the glove mucking the works up so I took it off completely and did it "in the buff".
I found the volatile nature of the acetone on the skin quite refreshing actually. I should have applied some to my temple after the third failed try to cool my head off.
That aside, my wife doesn't show any inhibition with nail polish remover which is essentially acetone, and it apparently doesn't bother her fingers either. The process of getting the old film layer off was quite quick actually as well, just 2 or 3 minutes.
Peter, Sorry for your tribulations. Thanks for showing me the insides of the smga-I had them for 15 years and always wondered what was behind the socks.
Isn't that a wonderful sound coming from those speakers? In a way I like it better than the 1.6's I now have. Maybe it's because they were my 1st mags, but they have such a musical quality, they really grow on you.
I'm curious if you listened to them after they were repaired with the socks off AND on to see if the fabric affected the sound since it is so thick. It may be a good tweek to get a more transparent material for the socks.
No, no socks yet. I first wanted to make sure all the re coiling was done, and now I am going to upgrade the cap and coil. It will be a while yet until they are dressed.
I don't know, they had the black fabric which is better than the old white stuff magnepan used to use. (which was like a burlap sack) I had to buy some new material not long ago to fix a TV grill for someone and that stuff seems identical to what's on there now, so I don't think a change is needed.
Yeah, I think the SMGa has always been the most highly regarded of the small maggies. I think it's the width. I have never understood why magnepan never experimented more with width, but it appears they don't experiment with much of anything. But that is why I chose this model when I went looking.
After the cap and coil get replaced, I am going to build a solid oak deck, bass wing and butress bar stand for them with brass footings. The metal leg with the assinine "flip" wire angle adjuster is so awful it makes using 3m 77 look appealing.
I'll be doing a write up on the crossover upgrade when that is done as well.
Thanks for the reply, and yes, they do sound really nice, even as is.
Hey, thanks for the great "saga" post. You have much more patience than I, Sir. That's why I gave up and sent my 0.6QR to MN and let them do the fix. All said and done, +/-$400 was worth it for my blood preasure alone!
There was NO way I was going to let the damn 3M win. :^ )
Hopefully now, nobody else will go thru the misery of trying to do this with it. Let the 3M rot on the shelves folks, I guarantee whatever it is you need to do, there is a better product for the job out there.
I have been using DAP contact cement for some time to glue in mylar for electrostatic panels. No problems. Same with acetone on mylar. No problems.
I was afraid the water based stuff wouldn't have the same "bite", and I also worried about longevity. What has been your experience? It is true there is no room for error with the acetone DAP. The parts touch, it's over.
Yep solvent based contact cement leaves little room for error!
I have used the water based version to attach the mylar to the stator assembly. This would be a critical connection since any shift in the contact cement would allow the mylar to loose tension. I also use this for assembly of the spacers etc.
I find the water based does just as good a job as the solvent based, it just takes a bit more time to set-up. I have just started using the water based so I have no long-term results to report. The latest pair of panels I built are in transit to another individual for evaluation. They will be disassembled for inspection and mylar tension will be a key area of evaluation.
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