DIY Magnepan SMGa repair

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Peter Guns Smga pell fix.....I like to look.....



MUG Tweaks
 

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thanks Pano

BTW for those that might be thinking about using foil rather than the wires in the bass section on these designs...

The wire as significantly more rigid than the foil would be. This rigidity, in the bass diaphragms anyway, is part of the control this diaphragm has over standing wave activity. It is not likely you will get the same bass performance with foil as U would with wires.
 
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thanks Pano

BTW for those that might be thinking about using foil rather than the wires in the bass section on these designs...

The wire as significantly more rigid than the foil would be. This rigidity, in the bass diaphragms anyway, is part of the control this diaphragm has over standing wave activity. It is not likely you will get the same bass performance with foil as U would with wires.

And yet Magnepan switched to using foil, exclusively, some years ago. :confused:

Andy
 
Thanks Pano


And yet Magnepan switched to using foil, exclusively, some years ago. :confused:

Andy

Ha maybe Im confused?

I have no doubt they switched to foil on tweeters. But did they switch to foil on woofers also??

It certainly can be done that way however I suspect ( depending on the width/ thickness ratio of the "foil") they would likely need to re tune the placement/ number of the buttons to accommodate a somewhat different mechanical property than the stiffer wire system IF the "foil" was truly very thin and spread out width wise.
 
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Here you go. As best I could measure wire to wire spacing on the tweeters is 0.2" and on the woofers 0.326"
Magnepan MG-IIIb Or maybe it's 8.3mm and 5mm

Center-to-center is 8.19 mm for bass and 5.46 mm for tweeter. It is easier to measure on the perforated sheet metal. Sure, they switched to foil on most drivers but they also changed more than just that. The Mylar is probably tensioned in another way and the tie-down scheme is different. Foil will reduce the possible tension/excursion of the diaphragm and this must be compensated for.
 
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Have you seen the tooling that enables the spacing in production?
It’s pretty slick; you take a piece of Masonite and carefully drill some holes for steel dowel pins where the wire will be routed around. Then, when the circuit is complete, the Masonite with wire is placed over the Mylar and pushed onto it, allowing the dowel pins to retract. When the Masonite is removed, the wire has transferred to the Mylar.
 
Old musty thread

Interest in Maggies seems to be pretty much dead but they are interesting, and can sound great.
I have rewired several tweeters with copper wire and compared them to the original aluminum wired ones. Using I think it was #36 wire the DCR came out almost exactly the same using a 4 wire ohmmeter. Maybe just me but they sounded the same and measured the same on the top end rolloff.
the panels cry out (literally) for some stiffening, how depends on what model you are looking at. They are are fertile ground for mods and much improvement is possible as they are made for a specific profit point (the stands are awefull!)
crossovers are el-cheapo in the older ones, and since they are within the cloth are hard to play with. Best bet is to run all wires out to an outboard box which can sit on top of the stand in back. They do like lots of power and mating with a sub is tricky. Don't even bother with a wimpy sub ( I use 4 15" woofers at low levels)

All in all they can sound great and are a fun project to monkey around with.
 
The mass of a copper is double to aluminium for a given resistance. It should make a difference. Magnepan has tried to recue the moving mass over the years. The moving mass of their best midrange drivers is less than the tweeters in older models. In the models where bass and tweeter share the same piece of Mylar, it is probably difficult to isolate the sound of the tweeter completely. In a dedicated tweeter is it easier to hear the difference while going for a lower mass diaphragm. It is just like a electrostatic speaker having 12 or 6 or even 3µm Mylar, there is a difference in high frequency sound reproduction.
 
What bands? In swedish: Vilka band? Du menar kanske tråden/folien?

The glue recommended by Magnepan is: 3M Scotch-Weld Spray 77 plus 3M™ Scotch-Weld™30 Water Based Contact Adhesive. These are the names used in Europe, in the US it is different.

Unfortunatley, you cannot buy the "30" in Sweden, you need to run a business for that. I have got mine in Germany, a brother in law helped me.

You can get a manual from me on the recommended process how to re-wire/glue. Send me a PM with your E-Mail address.

Roger
 
I hope no one complains if we write in swedish.

Det har varit problem med limmet under många år. Den metod som nu används/rekommenderas (sedan 2005) sägs ge en hållbar limning, långt bättre än tidigare. Hur gamla är dina SMG? Är det väldigt gamla brukar även tråden erodera bort och det blir brott och inget ljud. Du kan köpa tråd och lim från Magnepan. Eftersom limmet är vattenbaserat skickar de inte förrän mitten av april. Bifogar en bild, lim och folieledare m.m. Jag har en liter lim ståendes, har många renoveringsprojekt. Spray-limmet finns att köpa mera allmänt. Först kör man spray-limmet, lägger dit tråden och sedan målar man lite över tråden med det vattenbaserade limmet. Jag bor i Huskvarna. HAr du vägarna förbi får du lite vattenbaserat lim av mig.

An externally hosted image should be here but it was not working when we last tested it.
 
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