Magneplanar -- I'm doing the SMG crossover upgrades

I got the new 30mF Obbligato caps today. this time they were boxed neatly and arrived intact. This time they were not examined by my local post office.

I wired them in Parallel with the existing 22mF caps that were already in the crossover.
Theoretically, this should drop the crossover point from ~1100 back down to around 800 which closer to the OEM crossover point.

My first impression is that the high frequencies moved forward in the soundstage. There is a lot more fine detail including more delicately pronounced percussive instruments, strings have a much cleaner tonality, and I can hear tiny extraneous background noise that was present during the recording session. Such things as the breathing of an artist or the sound of a bow hitting the strings brings new vitality into a recording.

The much more apparent decay as the sound trails off into the stage adds much air and space to the overall presentation. Voices are still up front and center.

I'm going to let these latest changes settle and burn-in but I'm already enjoying the transformation. The improvement thus far is dramatic. They don't sound anything like the humble little SMGs I had four weeks ago.

Nice job all around Squeegy. I like your project boxes too. I guess I'll have to get to work on making some for mine. I probably won't be tinkering with my 1.6's much, although,if I do anything more, I'd probably try bypassing the fuse (think I'll mull over that one a bit).

Maybe your success might sway Feanor into taking the plunge with his 1.6's.

Tx,
Bill

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Originally Posted by bubslewis

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Maybe your success might sway Feanor into taking the plunge with his 1.6's.

Tx,
Bill

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It might at that! Congrats, Squeegy.

I was very VERY close to starting another project as a pair of MG-1s showed up near my home for sale for $99 on eBay. I contacted the seller who told me the speakers were in working order but no highs present from one side. The previous owner supplied a factory repair kit which was included in the sale but never installed. From the photos, the kit looked like a replacement air coil inductor and some misc connectors. Since these are very similar to my SMGs, my thought was approach the MG-1s in the same manner as my current speakers.

Someone ended up buying them for which I am thankful. I've already got several projects on my work bench which are still yet incomplete.

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Originally Posted by squeegy200

Bill,
You are very observant!
Peter Gunn discusses this at length in his postings and one his webpage. On my SMGs the OEM spec is 50mf. He actually started experimenting with a value of 10mf and worked up in increments. He posts the theoretical response curves for each in the discussion. He settled at 20mf for subjective reasons on the SMGa.

I am going to start at his ending point and work my way to the OEM value.

He also discusses at length the soldering points and how he dealt with those. There is detail on how he removed the socks and rewired. His website has several pictures and how he actually applied some of the same modifications to the other models in the Magnapan line.

I did not pay attention to the discussions of the other models. However, I remember him stating that he adamantly preferred the simpler SMG crossover applied to the larger models vs the OEM configuration.

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Mine are original SMG,s spec is 17uf....

[QUOTE=squeegy200]To my astonishment, upon closer inspection, my crossover wiring is unlike the SMGa of Peter Gunn. Its not even close to the SMG diagrams on the MUG user group site. I was perplexed at what to do last night.

Then I looked at Peter Gunns site once more and discovered my SMGs are wired similarly to the newer MMGs. As Bill noted, some of the tweeters on the newer panels have been reversed. The MMG solution worked.[/QUOTE]

I just got around to checking out Peter Gunn's website and I immediately saved his descriptions and very thorough instructions on re-attaching coils that came loose. My Maggies are only 4 years old and I'm pretty sure the coils are in good shape, but I'm sure glad I read Gunn's article for down the road. Everybody that owns Maggies should save this article. http://www.integracoustics.com/MUG/M...nn/repair.html

Bill

[QUOTE=bubslewis]

Quote:

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Originally Posted by squeegy200

To my astonishment, upon closer inspection, my crossover wiring is unlike the SMGa of Peter Gunn. Its not even close to the SMG diagrams on the MUG user group site. I was perplexed at what to do last night.

Then I looked at Peter Gunns site once more and discovered my SMGs are wired similarly to the newer MMGs. As Bill noted, some of the tweeters on the newer panels have been reversed. The MMG solution worked.[/QUOTE]

I just got around to checking out Peter Gunn's website and I immediately saved his descriptions and very thorough instructions on re-attaching coils that came loose. My Maggies are only 4 years old and I'm pretty sure the coils are in good shape, but I'm sure glad I read Gunn's article for down the road. Everybody that owns Maggies should save this article. http://www.integracoustics.com/MUG/M...nn/repair.html

Bill

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He has some good info. However if you plan on a rewire in the future, I wouldn't use DAP, as it works too well, and you will probably never get the wires off the Mylar without destroying it.
The 77 is merly used to hold the wires till you put the final and REAL adhesive on, that now being 3M 30NF.
Check out Alex's forum on a Maggie rewire, he uses a 12 volt power supply to magnetize the wires, and using the magnets in the speakers to hold them down.
2 benefits-#1 they are still repairable, and #2 you are putting less goop on the Mylar diaphrams, probably improving their speed/sound characteristics.

Hi Squeegy - After reading your postings on your xover upgrades I would like to know what values you ended up with for your xovers. I am considering upgrades to both my 1.5's and my MMG's.

Mate are you around to discuss your Maggie crossover components? Just want to know what you bought and where from. I've a pair of MMGs.
Ta :)

Adam

See the link below for any questions you may have about anything Magnepan.

MUG : Magnepan Users Group

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Originally Posted by thebaudelaires

Mate are you around to discuss your Maggie crossover components? Just want to know what you bought and where from. I've a pair of MMGs.
Ta :)

Adam

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Apologies for not being around much. I actually did arrive at a final configuration that was pleasing to my ears.

I used Obbligato Caps and the Jantzen AirFoil as the components and placed them into a generic project box. I will dig out the paper work and let you know where I sourced them. I'm very curious as some have used as an alternative the Solen caps for a different voice with similarly pleasing results.

These past few months, I've gathered the courage to dive deeper and reproduced the entire Peter Gunn modification with my humble SMGs

For example, I fabricated these boxes using poplar wood to serve as the final housing for the finalized crossover modification.
https://lh6.googleusercontent.com/-M...s640/322-2.JPG

https://lh3.googleusercontent.com/-5...%252520019.JPG

My woodworking skills and craftsmanship are nowhere near the skill level of Peter Gunn. However, despite my amateurish attempt at "Gunning" my own Maggies, the audible improvements are far beyond my expectations.

Very nice work there S200! Maybe some day I will mod my 1.6's.

Very nice work on those crossovers. I like the handles on the covers!

Great work, I used them in the late 80's bi amped with ribbons on the top. I could only imagine how these sound! :22:

First things first : thanks a lot Squeegy200, you've give me the guts to rip the socks and try to upgrade thoses SMG!! I'm french canadian so my english is not perfect, so be kind with my writing.

My version are first one SMG : frequency cut of 2400hz, inductance unknown but can assume 0.22mH, capacitor 17uf.



Here's my experience :
- Cut the wings to fit in my living room... WAF was an issu with the big and really brown panels. They are now 15'' wide. Yep bass is affected, little less.. Changed socks for black

- SInce I had 2 inductance layin around I had few test to perform. Really I wanted to experiment even though values seems way off. The value I have is 0.51 mH Litz (Solen) gauge 14, 0.51mh Litz (solen), and a 1.0mh with magnet core. About the desing I stayed with the same so it's first order serie.

- 1.0mH with +- 60uf (solen Chateauroux 250v) freq cut 600hz = crappy result, bass was good but really the mid cannot be performed by the High wires...

- 0.51mH Litz with 31.8uf (Solen chateauroux 250v 30+1.8) freq cut 1250hz. Lot better results : mid are there but still a little off and lifeless (like dynamic boxy speakers). I tried to lower the capacitor value so the curve would add to boost mids, little better but...



I went back to Solen (yep, near my house ;)) and get the original value : 0.22mH Litz gauge 14 with 13.6uF (Chateauroux 250v 1.8+2.7+9.1), Freq cut 2400hz. The result was really really good, better than the original for sure but I wasn't happy about a thing : mid were too present now... geez... So I try to create a gap between curves. My best result was with 9.1uf! Quite a big gap!

For the future : frame upgrade and buying finest quality cap!

Hello everybody.

I also own the original 17μF smg and I am a bit confused about the route that I should follow. Probably, I will follow Malenurse's route, since I do not want to change the inductor. So, you are suggesting a 9.1μF, instead of the original 17μF. Have you made any further experiments? I will probably try both 17μF and 9.1 μF caps. Also do you believe a new inductor will have any sonic difference?

Thank you

Regards
Papadakos Panagiotis

Well, since nobody replied, I got a pair of 10μF and 6.8 μF Obbligato capacitors and replaced the original 17μF TSI ones. I am really enjoying the result (although the new capacitors have not burnt in yet). Soundstage has grown and a bit of the previous muddy midrange has been removed. Also, I can hear easily more details and the previous tiny sweet spot of the speakers has grown. So it is a recommended and cheap upgrade for all SMG owners.

Panagiotis Papadakos

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Originally Posted by PanagiotisPapadakos

Hello everybody.

I also own the original 17μF smg and I am a bit confused about the route that I should follow. Probably, I will follow Malenurse's route, since I do not want to change the inductor. So, you are suggesting a 9.1μF, instead of the original 17μF. Have you made any further experiments? I will probably try both 17μF and 9.1 μF caps. Also do you believe a new inductor will have any sonic difference?

Thank you

Regards
Papadakos Panagiotis

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