So i bought some sick maggies.

ericj

Well-Known Member
I've wanted a pair of maggies for some time now. Thing is I'm cheap. I'm sure you understand. Most of my speakers came home from the thrift store - starting with the ADS L810's I picked up for $24 in 1995.

Never seen a pair in a thrift store or pawn shop. I don't really spend much time in pawn shops because they seem to have a lower grade of audio gear than the thrift stores here. The whole electronics section seems to always be stuffed with things that people waited in line to buy on black friday.

So i troll craigslist and other local for-sale listings, and they always seem to pop up when i don't have any money, or someone else snatches them up, or the asking price is just too high.

Until now. I came home with a pair of gimpy SMGa.

He said they were his dead uncle's speakers. I think the truth is that he buys delinquent storage units. He's a huge fan of cerwin-vega speakers and I was prepared to pay the asking price if they were perfect.

They were not perfect.

In fact, one of them barely makes sound at all.

He got less than half what he was asking, which was still more than i wanted to spend for a project. But they don't appear to have been abused. There doesn't appear to be any corrosion on anything or evidence that they've been left outside at any point. Well, part of the sock on one of them has some schmutz on it toward the bottom. These have the black socks and I'm tempted to go another way when i reassemble them.

Only a few of the wires are visibly lifted on these.

The tweeters worked fine when i shorted out the blown fuses.

The one of them sounds ok until you turn it up and then you hear the distinctive sound of wires flapping against the membrane.

The other one is the real problem. It sounds like it is only making sound from one spot, high up on the right hand side of the panel.

But i have Mad Skills and the ability to throw caution to the wind. And to hand a guy $50 more than i think he really deserved. But exotic speakers are more rare in utah than a lot of places.

I've read a few of the magnepan repair threads here and elsewhere. I understand that i need some acetone, a sponge or something that isn't melted by acetone, some above average contact cement, and a water-based 3m product with a name that escapes me. And patience. And a work space.
 
Yup. I've read that one - much of it anyway. I need to look up the recommended parts to rebuild the crossovers as well, and place an order with Madisound or someone.
 
I trolled through a bunch of threads about maggie repair, or at least maggies-with-solid-wire repair.

I'm not going to use a spray adhesive because i don't want to fight with overspray. In fact, I'd prefer to stick down one loop at a time.

I've seen mixed reports about how well DAP Weldwood contact cement works - which was what Mr. Gunn (if that is his real name) was recommending.

With some digging through forums for people who use a lot of contact cement, I think i sussed it out -- There is more than one product with that label.

You can get the high-VOC, use in a well ventilated area, keep away from flame and spark stuff.

And you can get low-VOC, no strong odor, neoprene based stuff.

Guess which one works better?

Anyway. Looks like i am going to the hardware store for some acetone after work, and I'll be looking for some highly flammable contact cement. Which might have to be sourced from a craft store.

"Milloxane" = 3m Fastbond 30-NF, which is what you get if you order adhesive from magnepan directly, though they add a uv-protectant. And they don't ship it in the winter. A lot of people say this doesn't really work to stick down the coils, but most still recommend painting a coating of it over top. OK. Looks like $30/qt on up. ow.

I hear that it can be sourced from Grainger. I might have to step into a local outlet.
 
Good luck. As an ex-Maggie owner I think you'll be happily surprised. If not you'll have no problem selling them.
 
I have high hopes. And i own a large number of planar headphones of various technologies.

I've only heard one other set of maggies. They were big ones, at a shop that sells audiophile gear, and they were convinced that a 40w tube amp was doing them justice. it was hard not to talk crap - they were sponsoring an event i was attending, so i had been admonished not to burn 'em.

But that experience had all the telltale signs of not enough power.
 
I Peter gunned a pair of these. Staples, staples and MORE staples.

Since your reading up no advice needed I'm sure. "Careful around the mylar."

They eat power like pac man.

GL!
 
I tried my maggies with some 15 watt mono amps once, it wasn't pretty. But surprisingly my 150 watt Technics integrated drives them quite nicely.
 
Yeah, I do wonder if i'm gonna need a new amp. But i have a few that claim 100+ watts.
 
...

I'm not going to use a spray adhesive because i don't want to fight with overspray. In fact, I'd prefer to stick down one loop at a time.

I've seen mixed reports about how well DAP Weldwood contact cement works - which was what Mr. Gunn (if that is his real name) was recommending.

...

The spray adhesive works well for tweeter wires, and there really isn't much over spray, but I have not found it to work for the larger wires. I'm going to be using Dap Weldwood on my MG-I's as soon as I get another project finished. It does bond to the Mylar, but there is only one chance to place the wire, so be careful. I've found the other type doesn't work at all. Paper towels are fine with the acetone for wiping off the old adhesive, but you'll need a rubber glove that doesn't melt. And good ventilation.

I was not aware of Magnepan adding anything to the 3M product, and all the reports I've managed to come up with say the stuff doesn't seem to work well as the Weldwood, but does work well to seal the wires after bonding, which will help prevent corrosion issues in the future.

Overall, it's not an especially complicated project. Just a bit tedious.

And Gunn isn't the fellow's real name; he admits it on his website.
 
Contact Magnepan and see if you can get them to send you their official repair kit. About 15 years ago I was given a free pair of SMGa's and one was damaged. I gave Magnepan a call and they quite generously sent me everything needed to repair them for the cost of shipping the stuff. Aluminum wire & solder, all the solvents, sealers, adhesives and fixatives they use in house for repairs. I powered them with a BGW 500D. I sold them last year for $275 on Craigslist.
 
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That explains a lot.

Hard to see but there are two wires broken.

I already have aluminum solder paste.

I also have some of that indestructible orange kapton adhesive tape.

Wish me luck, guys.

Edit: or, maybe mylar sail window repair tape -- http://www.amazon.com/PSP-Marine-Tapes-Mylar-Repair/dp/B0051FD54M/
 
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First stage cleaning went just fine. As feared, that patch in the middle is completely torn out.

I got a box of wood+cotton q-tips at biglots for a buck and used that as my primary method, with acetone.

Followed by swatches of Dupont Sontara EC creped blue wipes. These are an engineered cleaning wipe, and they did a pretty good job of drawing crud out from under wires. Also with acetone, primarily pushing them around with stainless steel (not very magnetic) hemostats.

These are just supplies that i have around. I found a pack of sontara wipes at a thrift store four or five years ago for something like five bucks. At the time i just thought they looked like good quality shop towels. Almost ran off the road when i glanced at the package again on the drive home and couldn't believe that i'd bought something with the name of a Dr. Who villain embossed on it. It turns out that they are GREAT shop towels.

I'm still using wipes from that same pack, when a job warrants it. They are the opposite of cheap, so when i run out i doubt i will ever buy more. Here's what i mean by not cheap: http://www.rydoexpress.com/ProductDetails.asp?ProductCode=HOSPR811&Click=3327
 
To hold down the end loops of the wires, I used a hand full of large, steel fender washers. These are held in place by the magnets on the other side of the mylar but can be lifted off after the Weldwood stuff cures. You install them after you've painted the Weldwood and situated the wires in place.

That break around the riveted button, however, is a different story. I'd be on the phone to Magnepan followed with pictures of the break for consultation. My contact with them was excellent.

Agreed with other posters:

1) They'll work well once restored.

2) They eat power for lunch and will seem to absorb all you can give them.

Cheers,

David
 
To hold down the end loops of the wires, I used a hand full of large, steel fender washers. These are held in place by the magnets on the other side of the mylar but can be lifted off after the Weldwood stuff cures. You install them after you've painted the Weldwood and situated the wires in place.

That break around the riveted button, however, is a different story. I'd be on the phone to Magnepan followed with pictures of the break for consultation. My contact with them was excellent.

You mean the wire breaks? I've seen photos of them soldered back together. And since the breaks are right at the button, it doesn't matter much how stiff they will be.

I've got a syringe of this solder paste: https://www.solder-it.com/shop/item.aspx?itemid=89

It looks like the aluminum is anodized or coated with something so i will probably use some sand paper or a knife edge to get bare aluminum for the last couple mm of each end.

And I'll probably clamp the ends together for soldering. Probably with some stainless steel tweezers + rubber band we'll see what works.

I'd heard of the fender washer trick before. I've got various steel washers holding stuff down right now. Where i had the most wires lifted, I've got some larger pieces of steel.

The DAP Weldwood worked really well.

I still haven't sourced the other product. I need to call around tomorrow to see if any of the local industrial supplies or woodworking shops have it in stock.

As for the big hole in the mylar - yeah, I might need to get on the phone with magnepan and ask for advice.

I ordered a roll of 50mm wide polyimide tape. The gold stuff that electronics are held together with. That's wide enough to patch the whole span. I figure i will cut out two mirror image patches and insert one on the magnet side first.

But you're right. I should give them a call and see what they say. Worst case scenario either way is that i need a new driver. Which is surely an expensive proposition.
 
Yep, the flaring tool gets the job done ok.

On the repair of the busted wire, I'd not attempt to repair it. Just pull all the wire up and redo it. I can't recall what I used to make the U shaped ends where the wire turns around but it was a piece of plastic pipe that was the diameter I measured from the original.

On the mylar repair, since you're going to need to repair the mylar, you're going to have to clear the area anyway, so why not do the right thing and just pull all the wire off and redo it completely? I'm not convinced that you're going be able to repair the wire break anyway. The wire is finished with an enamel that will typically take heat to burn off. You don't have that option with it attached to mylar.

Sometimes it just pays to work you way back out of the problem.

Cheers,

David
 
Yep, the flaring tool gets the job done ok.

On the repair of the busted wire, I'd not attempt to repair it. Just pull all the wire up and redo it. I can't recall what I used to make the U shaped ends where the wire turns around but it was a piece of plastic pipe that was the diameter I measured from the original.

See above wrt "mad skills". I am entirely confident that i can solder the wires. Not my first rodeo, and all that. I've also come across pictures of other SMG and SMGa drivers on which wires had been successfully soldered back together.

I've worked with enameled wire many times before. knife edge, fine sandpaper, etc, not a big deal.

Ironically the big hole in the mylar makes the wire repair easier, since i might end up patching with polyimide - which can withstand a sustained temperature of 842F and short excursions as high as 1299f without deforming.

Even if the mylar were intact, I could just slip some card stock and a bit of thin copper foil (facing the mylar) under the wire.

The solder paste i have makes a good joint at 400f. I have an excellent constant-temperature (TC series) Weller solder station with a selection of tips from 600f to 800f (yeah the tip sets the temperature, by way of a magnetic switch and the curie point of a slug on the butt end of the tip. It's a really clever system.)

It'll be fine.

Part of the deal here is that those wires are already stretched, so there will be an overlap of a few mm. That joint will be really stiff compared to the rest of the driver, but the breaks are exactly at the edge of the button, where the wire shouldn't be moving anyway.
 
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