So i bought some sick maggies.
- Thread starter ericj
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- maggies magnepan magneplanar smga
Call mag epa. They will sell you a re build kit cheap my first rebuild was also smga gray socks black wood two friends got into a bidding war over tbem then i did 2nd pair for for the loser (loser friends haha)they still love em years later,I tried buying back with no luck .. Thats okay wait till they see my secret project. (Tympanis) when i finish em!!!
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Find an older tbreshold you will be vrry happy with that co.mbo
ericj
Well-Known Member
The wires are aluminum, right? And they are anodized or something, as well. Aluminum metal oxidizes sort of immediately upon exposure to oxygen, but that layer of oxide is transparent. So, all of the aluminum metal you ever saw was oxidized.
Did you use aluminum solder? Without special flux, you can't really get solder to stick to aluminum very well. I am not sure that tin-lead solder will ever make a decent joint with aluminum.
Which is why i have bought solder paste specifically for aluminum. It's a mixture of appropriate flux and powdered solder with a metallurgy specifically for this job.
ericj
Well-Known Member
So here's the other one. Not as bad. Still bad.
There's a small tear that didn't make it into this image, too.
These are showing up, right? google photos has been going through some changes lately.
Thinking about folding those stretched wires right under the button. Not sure what to do with the ones on either side. cut & solder seems drastic.
There's a small tear that didn't make it into this image, too.
These are showing up, right? google photos has been going through some changes lately.
Thinking about folding those stretched wires right under the button. Not sure what to do with the ones on either side. cut & solder seems drastic.
ericj
Well-Known Member
More progress. I've got all the loops at the ends glued down. the 2nd driver is gonna rest for the next 24 hours or so with washers holding down the loops.
Still haven't acquired the 30-NF / Milloxane / whatever. Which brings up the point: the water-based weldwood seems to be the same basic polychloroprene adhesive as 30-nf. It doesn't have as good of a reputation, and it's a lot cheaper. I might try it if i find it locally, at $12/qt instead of $40/qt.
In any case, with the water-based contact adhesives, it sounds like it is imperative to test it before you go slathering it on anything that matters. There are a lot of reports of the water-based weldwood never actually curing. Probably due to having been frozen at some point.
Oh, as for the "turned green due to age" theory -- 30-NF is available in green. Why? dunno. You'd have to ask someone who applies a lot of veneer.
This whole situation at the center bothers me.
FWIW magnepan recommends driver replacement in any case where the membrane is torn. Perhaps they just replace the membrane and wiring? Since the magnetic structure is still good.
Still haven't acquired the 30-NF / Milloxane / whatever. Which brings up the point: the water-based weldwood seems to be the same basic polychloroprene adhesive as 30-nf. It doesn't have as good of a reputation, and it's a lot cheaper. I might try it if i find it locally, at $12/qt instead of $40/qt.
In any case, with the water-based contact adhesives, it sounds like it is imperative to test it before you go slathering it on anything that matters. There are a lot of reports of the water-based weldwood never actually curing. Probably due to having been frozen at some point.
Oh, as for the "turned green due to age" theory -- 30-NF is available in green. Why? dunno. You'd have to ask someone who applies a lot of veneer.
This whole situation at the center bothers me.
FWIW magnepan recommends driver replacement in any case where the membrane is torn. Perhaps they just replace the membrane and wiring? Since the magnetic structure is still good.
Mine either.
ericj
Well-Known Member
Stopped by a woodworking supply store tonight and picked up a quart of DAP weldwood water-based contact cement at half the price of 30-NF -- quarts being the smallest quantity they sell. I hope / expect, based on the safety data sheets, that for the purpose of just coating the repaired sections of the driver, it's basically the same sort of polychloroprene adhesive as 3M 30-NF.
And since i got it from a woodworking supply specialty store, I figure there's a better chance that they know that it shouldn't be allowed to freeze, and have a financial incentive to prevent it from freezing. But I'm still going to test it on some pieces of cardboard and plastic film and stuff before i put it on the maggie drivers.
And since i got it from a woodworking supply specialty store, I figure there's a better chance that they know that it shouldn't be allowed to freeze, and have a financial incentive to prevent it from freezing. But I'm still going to test it on some pieces of cardboard and plastic film and stuff before i put it on the maggie drivers.
ericj
Well-Known Member
So i haven't actually done much to these maggies in a couple weeks.
I did get some 22uf solens in from Madisound. You may have opinions about what might be better caps, but believe me, solens are ritzy for me. I don't generally believe in boutique anything. I make a concerted effort to cut through the haze of fashion and hearsay to what i can actually hear with my own ears and enjoy.
So yeah, four 22uf Solen caps, plus some A/D/S branded 6.8uf caps, bought as overstock from goldmine electric a few years ago, which are bigger than other 6.8uf polypros i have that have a higher voltage rating. So i think i will do ok.
I'm debating buying the 14ga 0.75mH foil inductors from ERSE. I enquired about the 0.80mH not being in stock and the answer i got was "sorry, we ran out of foil" - and how do you argue with that? Again, I am skeptical of whether the foil inductor will be better than the original, but I'm open to the suggestion, and the 0.75 14ga is somewhat economical and will almost fit in place of the original.
I have my 50mm wide polyimide adhesive tape. I've subjected it to some abuse and satisfied myself that it is a quality cured polyimide with a solvent-resistant adhesive regardless of having been branded "KOPTAN". Oddly, having a hilarious near-miss brand name is more comforting to me than a poorly reproduced and obviously fake DuPont or 3M logo.
But i think i have come over to the school of thought that perhaps i should use the non-sticky side of the film and some contact adhesive for my patches.
It's the stretched wires that have me paused. It seems like there is a couple mm of slack to take up in a few of the wires, where they were bulged out around the button.
One thought i had was to strip the glue and lift them all the way to the top of the driver, and then lay them flat starting at the button and advancing toward the top. This shouldn't be harder than laying down any other loose loop of wire, right? And the end of each loop is basically inactive, since it is too far from the magnet to begin with.
I have also decided that i need to gain more confidence in soldering aluminum. And i decided i want more than one method available for practice, so i ordered a small bottle of aluminum soldering flux and some tin-zinc solder from an outfit that sells them on ebay for the express purpose of soldering aluminum speaker coils.
So that's where i'm at with things.
That and annoyed that i can't fix my images unless i subscribe.
I did get some 22uf solens in from Madisound. You may have opinions about what might be better caps, but believe me, solens are ritzy for me. I don't generally believe in boutique anything. I make a concerted effort to cut through the haze of fashion and hearsay to what i can actually hear with my own ears and enjoy.
So yeah, four 22uf Solen caps, plus some A/D/S branded 6.8uf caps, bought as overstock from goldmine electric a few years ago, which are bigger than other 6.8uf polypros i have that have a higher voltage rating. So i think i will do ok.
I'm debating buying the 14ga 0.75mH foil inductors from ERSE. I enquired about the 0.80mH not being in stock and the answer i got was "sorry, we ran out of foil" - and how do you argue with that? Again, I am skeptical of whether the foil inductor will be better than the original, but I'm open to the suggestion, and the 0.75 14ga is somewhat economical and will almost fit in place of the original.
I have my 50mm wide polyimide adhesive tape. I've subjected it to some abuse and satisfied myself that it is a quality cured polyimide with a solvent-resistant adhesive regardless of having been branded "KOPTAN". Oddly, having a hilarious near-miss brand name is more comforting to me than a poorly reproduced and obviously fake DuPont or 3M logo.
But i think i have come over to the school of thought that perhaps i should use the non-sticky side of the film and some contact adhesive for my patches.
It's the stretched wires that have me paused. It seems like there is a couple mm of slack to take up in a few of the wires, where they were bulged out around the button.
One thought i had was to strip the glue and lift them all the way to the top of the driver, and then lay them flat starting at the button and advancing toward the top. This shouldn't be harder than laying down any other loose loop of wire, right? And the end of each loop is basically inactive, since it is too far from the magnet to begin with.
I have also decided that i need to gain more confidence in soldering aluminum. And i decided i want more than one method available for practice, so i ordered a small bottle of aluminum soldering flux and some tin-zinc solder from an outfit that sells them on ebay for the express purpose of soldering aluminum speaker coils.
So that's where i'm at with things.
That and annoyed that i can't fix my images unless i subscribe.
ericj
Well-Known Member
Back in 2016 i bought a few different things marketed to make soldering aluminum easier but lost my nerve.
Today i had a "what have i got to lose" moment and went ahead and tried one of them.
Was sold on ebay as "super gold flux kit for soldering aluminum voice coils".
Small bottle of unknown flux (maybe it's the stuff that originates in russia?) and a small coil of solder. About $10. It's still sold there.
My wires got pulled way looser over the last 3 years. I should have, say, taped a sheet of cardboard over the driver instead of just leaning it up against a wall.
I used my hot air tool to heat the wires to flux and tin the ends. Probably a soldering iron would work too. But i turned the fan speed all the way down to minimum and turned the heat up to 450c and gripped the end of the wire with some locking pliers over a couple shop towels.
Dripped on some flux, boiled it off, clean it, repeated a couple times, then applied solder and more flux. Didn't go on too badly.
Then i moved the shop towels over the driver membrane, put a 100mm square sample of 1mm hard titanium plate on that (because it's a pisspoor conductor of heat), taped down the wires in place with kapton tape, and soldered the ends together with some more flux and some more solder.
A ceramic tile would work for that job too. I just happened to have some pieces of titanium plate in my drawer.
I wouldn't be surprised if this is flux you really don't want to have on your hands, in your lungs, or long-term on your wires.
It turns out i have two more splices to make. I don't want to talk about it. Obviously, the proof will be in the dc ohms when the repair is complete.
Today i had a "what have i got to lose" moment and went ahead and tried one of them.
Was sold on ebay as "super gold flux kit for soldering aluminum voice coils".
Small bottle of unknown flux (maybe it's the stuff that originates in russia?) and a small coil of solder. About $10. It's still sold there.
My wires got pulled way looser over the last 3 years. I should have, say, taped a sheet of cardboard over the driver instead of just leaning it up against a wall.
I used my hot air tool to heat the wires to flux and tin the ends. Probably a soldering iron would work too. But i turned the fan speed all the way down to minimum and turned the heat up to 450c and gripped the end of the wire with some locking pliers over a couple shop towels.
Dripped on some flux, boiled it off, clean it, repeated a couple times, then applied solder and more flux. Didn't go on too badly.
Then i moved the shop towels over the driver membrane, put a 100mm square sample of 1mm hard titanium plate on that (because it's a pisspoor conductor of heat), taped down the wires in place with kapton tape, and soldered the ends together with some more flux and some more solder.
A ceramic tile would work for that job too. I just happened to have some pieces of titanium plate in my drawer.
I wouldn't be surprised if this is flux you really don't want to have on your hands, in your lungs, or long-term on your wires.
It turns out i have two more splices to make. I don't want to talk about it. Obviously, the proof will be in the dc ohms when the repair is complete.
ericj
Well-Known Member
My local makerspace has a smallish OMax waterjet system. Cutting area of something like 3ft by 6ft by like a foot thick of steel if you really want to stand around and wait for it. I had a crazy idea to make titanium plectrums that have a continuous width. Never figured out how to draw that shape, mathematically accurate anyway, in 2d CAD.
I hear that lead flashing is good for adding mass to speaker cabinets.
I'm gonna have to read up on the mylar repair advice again. A little stressed about that.
I just went through this with a pair of MG-1. I had a break that I tried to patch using foil tape, conductive glue, and some pieces of alumininum. Could never get a consistent 5 ohms DCR on the bass wires. Finally I gave up and bought the bass wire kit from Magnepan. When stripping off the old wire, I discovered that there were in fact *two* breaks, the second one being so small I could not see it.
It’s critical that the DCR of the left and right speaker sections match, BTW.
Maybe you will have better luck than I did; I’ve seen some people report here that they just slapped some aluminum tape over the break and had no other problems for years.
GD70
Lunatic Member
Good to see you became inspired again to get these done. You'll be very happy you did. I restored a set of SMG's last year, and they are amazing speakers. Use a good sealed sub with yours and you'll be in sonic heaven!
Let's see more pics and some details of the crossover work.
Glenn
Let's see more pics and some details of the crossover work.
Glenn
ericj
Well-Known Member
Finished my wire joints.
The main run measures 4.1 ohms so that sounds like a success to me? I haven't measured the other panel.
Bottom line, this flux and solder combo works.
And it WILL ruin the tip on your iron. Have sandpaper or a file handy, and a tin of tip refresher / tip tinner compound, like this:
https://www.amazon.com/Thermaltronics-FBA_TMT-TC-2-Lead-Tinner-Container/dp/B00NS4J6BY/
Maybe if you have a hot air system that is hot enough to boil off the flux that is a better way to tin the wires. I just used the 800f wedge tip this time, and i had to clean it and re-tin it twice for each joint.
The smoke isn't nice either. Have a fume extractor, fan blowing away from you, or a good cross breeze.
I wouldn't say it was hard to make the joints. Tinning the ends of the wires is tedious. heat, flux, heat, flux, heat, flux, heat, solder and flux, etc. Eventually, it takes.
The main run measures 4.1 ohms so that sounds like a success to me? I haven't measured the other panel.
Bottom line, this flux and solder combo works.
And it WILL ruin the tip on your iron. Have sandpaper or a file handy, and a tin of tip refresher / tip tinner compound, like this:
https://www.amazon.com/Thermaltronics-FBA_TMT-TC-2-Lead-Tinner-Container/dp/B00NS4J6BY/
Maybe if you have a hot air system that is hot enough to boil off the flux that is a better way to tin the wires. I just used the 800f wedge tip this time, and i had to clean it and re-tin it twice for each joint.
The smoke isn't nice either. Have a fume extractor, fan blowing away from you, or a good cross breeze.
I wouldn't say it was hard to make the joints. Tinning the ends of the wires is tedious. heat, flux, heat, flux, heat, flux, heat, solder and flux, etc. Eventually, it takes.