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Old 7th March 2009, 04:55 PM   #1
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Default Magenpan Mgiii Modifications

I am a long time Maggie lover (from the original MG2167 days) and, although I love my MGIII, have always wondered if there are easy to do improvements to be had. I have seen companies that offer modifications for SMG or any integrated tweeter panel, but not the ones with ribbon tweeters. Most of those mods involve building a new frame that is stiffer and has a more secure attachement of the speaker innards to the new wood frame, as well as removal of the rear grille cloth and higher quality crossovers and also rear angled supports.
Has anyone done any kinds of improvements to their maggies (MGIII), I would be interested to hear about them.
THanks
JC
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Old 7th March 2009, 06:38 PM   #2
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Have you checked out MUG?
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Old 8th March 2015, 01:51 PM   #3
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Default Magnaplanar MGIIIa repair help

Hi. First, I have never posted to a forum before, so please forgive me if I am not following protocol.
I own a pair of MGIII a Magnaplanars which have been heavily modified in the crossovers by the previous owner. I just purchased a McIntosh MC302 power amp to drive these speakers only to find that one of the woofers is not functioning. I discovered through simple continuity testing that one cap, a Solen PB-MKP-FC 56uF 400VDC was open with no continuity. I am planning on replacing it ASAP. My questions are:
1. Is this an adequate voltage for this cap? Or should I go to a higher voltage? (I read that a good rule of thumb is to use a voltage cap that is double the maximum voltage.)
2. Should I replace the other caps? (There are 6 caps on one speaker and 7 on the other)
3. Does it matter if I use a different manufacturer than Solen?
4. Can anyone offer any other advice to improve this speaker setup, per the background below?
Background
The speakers were made in 1987 and given to me by a friend of a friend who knew a lot about electronics. I have done some touchup gluing of the voice coils to the mylar panels over the years, but the speakers still sound great. I do not know how long ago the crossovers were built. I would like to get 2-5 more years out of them before upgrading them. I no longer have contact with the original owner. I would like to clean up the crossover network and upgrade in the process, if this is advisable.
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Old 8th March 2015, 02:17 PM   #4
john65b is offline john65b  United States
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400V is plenty for a crossover cap - why not match the Solen cap exactly? Nothing wrong with Solens.

I am not a big fan of rolling caps...as long as you don't sub a Polypropylene type with an electrolytic....

There are plenty here who will offer up Boutique expensive cap advice... Solens, Wimas, Clarity, REL, take you pick....
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Old 8th March 2015, 03:02 PM   #5
Davey is offline Davey  United States
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Bob,

A capacitor would normally show open with a continuity test.
In looking at the MGIII schematic.....even if you did have an open capacitor, it would not cause the woofer to stop operating.
I think you probably have something else going on here.

Dave.
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Old 8th March 2015, 03:11 PM   #6
john65b is offline john65b  United States
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Quote:
A capacitor would normally show open with a continuity test.
Whoops, didn't read that part...look at your wires up and down the panel. You have a break in the wire - check continuity at the coil wire ends - see if you have continuity there. Hopefully break is not on mylar and fixable, or an entire rewire is required...
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Old 8th March 2015, 04:30 PM   #7
AVWERK is online now AVWERK  United States
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As I remember this model had a inline speaker fuse? Bypass this and you will notice a difference for the better.
Gambling yes, but most speakers don,t use them for good ( sonic ) reasons.
Regards
David
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Old 8th March 2015, 04:50 PM   #8
Davey is offline Davey  United States
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JC,

I haven't seen too many DIY efforts on the MGIII speakers. A number of folks have paid good money and sent their speakers to aftermarket modifiers.

You can scan through the MUG board, but be warned.....you need to have your BS filter at maximum. A lot of flakes on that forum nowadays.

Cheers,

Dave.
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Old 12th March 2015, 06:14 PM   #9
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Quote:
Originally Posted by rubidium7 View Post
I am a long time Maggie lover (from the original MG2167 days) and, although I love my MGIII, have always wondered if there are easy to do improvements to be had. I have seen companies that offer modifications for SMG or any integrated tweeter panel, but not the ones with ribbon tweeters. Most of those mods involve building a new frame that is stiffer and has a more secure attachement of the speaker innards to the new wood frame, as well as removal of the rear grille cloth and higher quality crossovers and also rear angled supports.
Has anyone done any kinds of improvements to their maggies (MGIII), I would be interested to hear about them.
THanks
JC
MG-III are really old and Magnepan have some issues, like glue not holding the wires or wires having breaks. If the drivers are not in the best shape, you need to rewire them or maybe send them to Magnepan for refurbishing (new diaphragms and wires). After that you can start looking for modifications.
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Old 13th March 2015, 01:43 AM   #10
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Default MGIIIa repairs

I purchased two new Jantzen 56uF 400 VDC capacitors, installed them yesterday (one in each speaker to maintain balance) and it solved the problem. The speakers sound FANTASTIC again! My friend who is a sound engineer said that my testing methods were sound and he was correct. Capacitors (at least this type) are supposed to show continuity.

My new McIntosh MC 302 is a great match for these speakers. Incredible. The speakers are tight and are holding together well for their age, despite some touch ups re-gluing the voice coils to the mylar over the years. I think the previous owner knew what he was doing when he bypassed the stock crossovers and built the suped up ones that are currently in place. I ran the speakers for more than three hours at between 200-300 watts last night and they just kept sounding better and better as the night went on. Thanks for your input. Happy listening to all!
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