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Magneplanar SMGa Repair - Any New Ideas?

62sunbeam

62sunbeam

Raconteur
I have a pair of Maggie SMGa that have come delaminated in the usual fashion and I was curious if there where any new methods for repairing them.

I used the Weldwood with Krylon Stays Clear over it on the last pair I had but I want to know if anyone has come up with a better way.

I have both the ends curling up and several sections in the mids that are lifting. The good news is no tears in the plastic film and no corrosion on the wires.

Thanks

Eric

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I used Weldwood Contact Cement after completely cleaning the wires and the mylar. I used 1" fender washers to keep them applied to the mylar as it cured. This approach used the magnetic field to pull the washers down onto the wires.

The first pair I redid, I then applied more Contact Cement after the wires had cured in order to be sure they would stay. I think that was a bit overboard and the second pair I redid used less of the stuff. I think this is more important for the tweeter wires.

On the tweeter wires, I used the same fender washer to hold them in place all up and down the lines. Also, getting the enamel off of the wire to solder them took some effort. I'd suggest you learn how to burn that stuff off with some spare wire first before trying the real thing. Give yourself some extra length when you apply them to be sure you can get them to adhere with the solder.

I tried different tweeter crossover caps by just clipping them in place and listening. Couldn't really hear much difference at all. The things do require some power to get going, too.

Hope that helps!

Cheers,

David
 
So I did the weldwood on the few loose wires there were as well as the ends but I find that the glue on the entire panel is so soft that I still get buzzing at high volumes and I don't get the volume I should out of the speakers. Basically the wires are pulling away from the mylar and then slapping back down into the old glue where they stick in the goop.

Short of removing ALL of the adhesive and ALL of the wires is there a solution?

I faintly remember when I did this the last time someone saying they sprayed 77 spray over the entire back of the speaker in order to reinforce the wires adhesion to the mylar. This would work I imagine but might effect the speakers sonics as well.

Has anyone found a solution to this particular problem?

Thanks

Eric
 
Before I actually sent mine back to the Mfg- I used 3M spray adhesive as well. It worked fine for a good while. When I started to have larger delamination isse I sent them back- $500 later, in new boxes I got them in top condition. I added a 10" Peerless XLS 1cu ft sub under each one xover at 60hz and had a wildly great speaker set. I recapped mine with Solens.

Due to the fact I had to move them out into the room a ways to playplace them properly , my wife over ruled the placement so I ended up selling them most unfortunately. They can be really nice speakers- hope you get your up & running soon.
DC
 
62sunbeam said:
So I did the weldwood on the few loose wires there were as well as the ends but I find that the glue on the entire panel is so soft that I still get buzzing at high volumes and I don't get the volume I should out of the speakers. Basically the wires are pulling away from the mylar and then slapping back down into the old glue where they stick in the goop.

Short of removing ALL of the adhesive and ALL of the wires is there a solution?

I faintly remember when I did this the last time someone saying they sprayed 77 spray over the entire back of the speaker in order to reinforce the wires adhesion to the mylar. This would work I imagine but might effect the speakers sonics as well.

Has anyone found a solution to this particular problem?

Thanks

Eric
Click to expand...

IIRC it is Krylon laquer that is sprayed on the panel to seal it once the wires are glued in place.
Try a google search over at the planar asylum of Audio Asylum.

Here's one thread, where Peter Gunn suggests doing this:
http://www.audioasylum.com/cgi/t.mpl?f=mug&m=152269
 
Last edited:
I had some of the delamination problems with the bass wires once I had rebuilt both ends where the pull up as in your pictures.

To find the offenders, I rigged up an audio oscillator that I could manually use to sweep across the spectrum. Using an amp with signal generator driving it, I could easily locate specific frequencies where you'd get a buzzing from the panel. Once I zeroed onto the freqency and got the panel a-buzzin' then I could locate it with my fingers.

To secure the offending point, I cleaned off the section with acetone, then applied Weldwood with a small brush. Lastly, I used those fender washers I mentioned to hold the wires down against the mylar until the Weldwood set up.

This is labor intensive, for sure, but can work quite nicely. BTW, how are the tweeter wires? They are likely falling into pieces, right?

Cheers,

David

62sunbeam said:
So I did the weldwood on the few loose wires there were as well as the ends but I find that the glue on the entire panel is so soft that I still get buzzing at high volumes and I don't get the volume I should out of the speakers. Basically the wires are pulling away from the mylar and then slapping back down into the old glue where they stick in the goop.

Short of removing ALL of the adhesive and ALL of the wires is there a solution?

I faintly remember when I did this the last time someone saying they sprayed 77 spray over the entire back of the speaker in order to reinforce the wires adhesion to the mylar. This would work I imagine but might effect the speakers sonics as well.

Has anyone found a solution to this particular problem?

Thanks

Eric
Click to expand...
 
dshoaf said:
This is labor intensive, for sure, but can work quite nicely. BTW, how are the tweeter wires? They are likely falling into pieces, right?
Click to expand...

Actually the tweeter wires are 100% solid. The only real issue is that the glue has gone gooey.

I'll have at it again tomorrow and post my results.

thanks

Eric
 
62sunbeam said:
Actually the tweeter wires are 100% solid. The only real issue is that the glue has gone gooey.

I'll have at it again tomorrow and post my results.

thanks

Eric
Click to expand...

Your Maggies look relatively nice. FWIW, I prefer using the solvent based Weldwood. The 3M spray adhesive has failed just about everywhere I've used it—just like the PG write up. I also used washers to hold the wires during the curing time. The process takes time but is not difficult.
 
Was the Milloxane even used on these speakers?

There seems to be the residue from the 77 spray on the mylar that is currently on the speakers has broken down into a tacky residue that barely holds the wires down as they vibrate.

It doesn't seem that there was a coat of Milloxane or any other sealant applied over the length of the wires. Maybe at the ends but not the rest.

What I'm thinking is this: If I am able to clean off most of the residue between the wires and spray a coat or two of the water based 3M contact cement over the length of the wires I might be able to get the wires firmly attached to the mylar to have these speakers singing again but before I do I want to know if there is even supposed to be this coat of sealant over the length of the wires. I don't want to affect the weight or stiffness of the driver.

Thoughts??

Thanks

Eric
 
62sunbeam said:
Was the Milloxane even used on these speakers?

There seems to be the residue from the 77 spray on the mylar that is currently on the speakers has broken down into a tacky residue that barely holds the wires down as they vibrate.

It doesn't seem that there was a coat of Milloxane or any other sealant applied over the length of the wires. Maybe at the ends but not the rest.

What I'm thinking is this: If I am able to clean off most of the residue between the wires and spray a coat or two of the water based 3M contact cement over the length of the wires I might be able to get the wires firmly attached to the mylar to have these speakers singing again but before I do I want to know if there is even supposed to be this coat of sealant over the length of the wires. I don't want to affect the weight or stiffness of the driver.

Thoughts??

Thanks

Eric
Click to expand...

There was, but it likely broke completely down from O3 and UV. That gooey stuff is the residue. I use PGs method and I'm happy with the results. I have not tried using 3M NF30 H2O based contact cement, but then I enjoy the smell of organo-solvents and know that Weldwood works well.

You've likely found this:

http://www.opus45.com/magnepan/
 
There's no way anything as heavy as what's shown in the page you sent me was ever applied to my speakers. What's on them is like the sticky part of a post it. Only not completely dry.

Putting that heavy coat like in your link won't affect the sound?

Thanks

Eric
 
So I spoke to Lauren? at Magnepan today and she said just wipe lengthwise with a rag damp with acetone to remove what I can of the old sticky residue and give it one coat of the white 3M contact cement and allow to dry.

Also, she said all the web fixits that say to use the green cement and more than one coat are wrong. Just saying.

I'll be doing this tomorrow and I'll report ASAP.

Eric
 
So the cement is dry and I hooked them up. First off I found the fuses to be blown but the speakers still played. How is this? I guess a schematic would help but it seemed like all the frequencies were being reproduced.

I replaced the fuses and there was a pretty big improvement.

Honestly I am under impressed but in all fairness the the receiver I have them hooked to is a mid 90s Sony Pro Logic unit that probably doesn't like the 4ohm load.

While I'm in there I figure a recap couldn't hurt. Has anyone done this and want to recommend a particular cap or caps for this particular speaker crossover?

Thanks

Eric
 
IIRC the fuses are for the tweeter section only. That would explain why they worked with no/blown fuses and why the sound improved with working fuses.
 
Ok, you'll now find out how much power these things will need to get going. Use the Prologic receiver for what you can get out of it. Then, if you can borrow a big-time pro amp of of some sort, do it. Pump the power to them, get them set up right and sit back for a few days of listening.

That's when you'll realize there's a lot of presentation there but not like you're used to. Only then would I recommend you start to form some opinions.

Ask me how I know this......

Cheers,

David
 
62sunbeam said:
So I spoke to Lauren? at Magnepan today and she said just wipe lengthwise with a rag damp with acetone to remove what I can of the old sticky residue and give it one coat of the white 3M contact cement and allow to dry.

Also, she said all the web fixits that say to use the green cement and more than one coat are wrong. Just saying.

I'll be doing this tomorrow and I'll report ASAP.

Eric
Click to expand...

If Lauren's talking about simply spraying them with 3M 77 , then I suspect the wires will come loose again. All Magnepans of that vintage had 3M spray contact adhesive followed by Miloxane. The 3M in the cited article is not any heavier than the Miloxane. Unfortunately, Miloxane breaks down over time from environmental conditions, namely, UV and ozone exposure. I dislike the water based green contact cement and prefer the organo-solvent version. BTW, there isn't a whole lot of difference between what Lauren's saying and what PG and all the MUG users say unless Lauren's talking about 3M 77.
 
bhunter said:
If Lauren's talking about simply spraying them with 3M 77 , then I suspect the wires will come loose again. All Magnepans of that vintage had 3M spray contact adhesive followed by Miloxane. The 3M in the cited article is not any heavier than the Miloxane. Unfortunately, Miloxane breaks down over time from environmental conditions, namely, UV and ozone exposure. I dislike the water based green contact cement and prefer the organo-solvent version. BTW, there isn't a whole lot of difference between what Lauren's saying and what PG and all the MUG users say unless Lauren's talking about 3M 77.
Click to expand...

No. What she recommended is to stick down any loose wires with weldwood contact cement ( I told her this is what I was using and she agreed it was a good choice and by the way they no longer use the 77 spray) and then brush on a coat of the WHITE 3M water based contact cement instead of the milloxane. I did and it's like a latex membrane holding the wires to the mylar.

I'll be trying them with a real amp today. Don't worry.


Still no suggestions for a cap?


Thanks

Eric
 
Thanks for bringing this up "62sunbeam". I also have a pair that needs to be disrobed and have the same done to it. Got a couple of good hints from Magnepan and others reading this thread. I used to drive mine with a Denon PMA-747 (80 watts) and it sounded pretty good. Imaging with SMGa's was phenomenal when I could find the best speaker positions. I just need to find a big, SAFE spot to do this so that they won't get damaged in the process. Solens make a good, cheap replacement for old caps, but I haven't done any work on these so I can't give any crossover help (I would like to improve mine too, so if I find anything on the interwebs I will post).
 
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