Magnaplanar SMGa - No Treble - Page 2 - diyAudio
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Old 24th April 2012, 10:35 PM   #11
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Right, no fuse is the same as a blown fuse. Did you check to see if the fuse is intact?

Sheldon
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Old 24th April 2012, 11:42 PM   #12
gootee is offline gootee  United States
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Use a multimeter set to read Ohms (Ω) and check:

1. With one meter lead on each end of a fuse that has been removed, it should read LOW, probably several tenths of an Ohm, or close to what it reads when the meter leads are touching each other.

2. With a fuse removed, measuring between the "+" speaker input and one of the fuse connections should give a very low reading, less than one Ohm (mostly just the resistance of the coil in the crossover). Measuring between the "+" input and the OTHER end of the fuse holder should then give about 3.2 Ohms (15 Ohm resistor [plus coil resistance] in parallel with 4 Ohm tweeter), if I'm looking at the crossover schematic correctly.

If the measurements from #2 are in the ballpark, your tweeter should be intact, electrically.

One thing I would probably replace first is the 50 uF electrolytic capacitor in the crossover. If it is an electrolytic type, and is original, then it's too old and has got to be replaced. You could use another similar electrolytic, or use a polypropylene. Just make sure the voltage rating is the same or higher.

If you don't have a multimeter or ohmmeter, you could jumper across the fuse holders with wire, temporarily at least, and try playing them at moderate volume to see if there is a difference. But chances seem pretty low that both fuses are blown.

For much more information, I suggest going to

The Planar Speaker Asylum

The crossover schematic is at

MUG Tweaks

Specifically, it's at

http://www.integracoustics.com/MUG/M...s/smg%20xo.gif

I do recommend also at least removing the "socks" that cover the speakers, so you can inspect the drivers and crossover components and connections, etc. There's plenty of info on all of that at the first link I gave.

Tom

Last edited by gootee; 24th April 2012 at 11:45 PM.
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Old 25th April 2012, 09:02 AM   #13
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Default Maggies with no Treble

Thanks Gootee

I'll do the fuse check but changing capacitors scares me to death. I have a friend who'll do this sort of stuff for me.

Brilliant information.

Many Thanks

Ronnie
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Old 25th April 2012, 09:06 AM   #14
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Default Maggies no Treble

Quote:
Originally Posted by rob g View Post
Ronnie,
Are you driving the speakers with the same amp?

Is there no high frequency coming from the treble section when you put your ear next to it?
Hi Rob

Haven't had time to do any more test yet.... but where do I put my ear ?? If there is no treble ....

Ronnie
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Old 27th April 2014, 05:13 PM   #15
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Saw this old thread and was wondering about the outcome with the treble? I just purchased a set of SMG's and they have no treble also. Would like more info on troubleshooting. will look at links provided, my first set of Maggies. Very, very disappointed righjt now.
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Old 30th April 2014, 02:55 AM   #16
andyr is offline andyr  Australia
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Quote:
Originally Posted by Freecrowder View Post
Saw this old thread and was wondering about the outcome with the treble? I just purchased a set of SMG's and they have no treble also. Would like more info on troubleshooting. will look at links provided, my first set of Maggies. Very, very disappointed righjt now.
You do know about the Planar Asylum, don't you?

The Planar Speaker Asylum

You should get lots of help there.

Good luck,

Andy
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Old 30th April 2014, 04:55 AM   #17
j beede is offline j beede  United States
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Magneplanars represent great value, new or used. The down side is that voice coil failure or delamination is usually just a matter of time. I recently replaced the tweeters in an old pair of MG-IIA. I used 30ga copper magnet wire instead of the factory aluminum wire and I was pleased with very slightly shelved down highs that resulted. The tweeters were easy to replace. After looking at the woofers--I decided not to try replacing them and repaired the broken voice coils instead. The worst part of the job is removing the staples that hold the "socks" in place. The hardest part was putting the old fabric back on. I did not have time to order fabric from Magnepan. I would not attempt to reuse the old fabric again. Good luck.
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Old 30th April 2014, 05:09 AM   #18
j beede is offline j beede  United States
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Quote:
Originally Posted by Freecrowder View Post
Saw this old thread and was wondering about the outcome with the treble? I just purchased a set of SMG's and they have no treble also. Would like more info on troubleshooting. will look at links provided, my first set of Maggies. Very, very disappointed righjt now.
Sorry to hear that. I gather you bought them before hearing them? The tweeters are very suitable for DIY, the woofers less so. You likely have multiple breaks in tweeter continuity due to corrosion. You will need to strip off the old tweeter wire with acetone and lay down new wires. You can buy wire and adhesive from Magnepan--$50 per tweeter as I recall. I used 30ga copper magnet wire ($4 for 200') and spray adhesive ($10). I was very pleased with the results. A set of "socks" from Magnepan is $90 as I recall. New cloth is virtually mandatory. FYI: I was not impressed with the aluminum soldering kit I bought locally.

Unless you are a serious DIY hobbiest you probably would be happier finding a cleaner/newer pair of used MMG for around $300.
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Old 30th May 2014, 07:43 PM   #19
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Just a followup. I did repair the woofer delam issues and put in the new tweeter kits from Magnepan. very nice speaker! Built homemade stands from shelf supports and got them up off the floor. Looking at active biamping now with MiniDsp. Lots of fun for a couple hundred dollars.
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