• RE: smga crossover components - ian.weitzel@btconnect.com 03:18:00 04/03/08 (7)
  In Reply to: RE: smga crossover components posted by badduh on April 02, 2008 at 08:22:07

  I have done the crossover upgrade for the SMGa - it is a well-covered topic on this forum. A search on "SMGa" and "crossover" will produce a morning's worth of reading. Also a search on "Peter Gunn" will give you chapter and verse from the guy who has probably done more of these than anybody else on the planet. The crossover design for the SMGa is very simple, with just one capacitor and one inductor, albeit with relatively large values and hence not cheap.
  
  For what it's worth I used a Madisound "Sledgehammer" inductor, which features thick wires wound round a laminated steel core - the general opinion being that this produces enhanced bass response over the standard inductor and is better for this purpose than an air-cored one. Madisound offer a service whereby they will unwind the inductor with the value above the one you require to exactly the value you need for something like a 20 per cent premium.
  I used a Solen "Chateauroux" capacitor, these being quite reasonably priced and available in the UK. Many contributors to this board don't rate them highly, although I think they are a great improvement over the stock offering. If I was doing them again I'd probably go for Ansars - a bit more (about $25US as oppsed to $17US) also fairly easy to source in the UK.
  
  The other issue is how to accommodate the new components, which will be considerably larger then the originals and will not fit into the narrow confines of the SMGa frame. The alternatives are either to construct some kind of "hump" enclosure attached to the bottom of the speaker that contains these components or to use a separate box to house them with the bass and treble outputs from the box wired ( either directly or via binding posts) directly to the woofer and tweeter wires on the panel. I did the former, but in the light of experience were I to do it again I think I would go the separate box route. The original components can be left in situ and just bypassed, meaning that the operation can be easily reversed should it be needed and a number of internal connections can be avoided, always a good thing.
  
  Anyway, I've had mine up and running for about a year now and the improvement is clearly apparent - more bass response, without losing the "naturalness" of the Maggie bass and an astonishing midrange - in the area of the female vocal range in particular.
  
  I can only wish you the best of luck.
  
  

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  • RE: smga crossover components - badduh@hotmail.com 04:09:57 04/03/08 (6)
    In Reply to: RE: smga crossover components posted by ian.weitzel@btconnect.com on April 03, 2008 at 03:18:00

    Thanks fore your answer.
    I already did some reading on this forum and also came across a couple of topics with answers of Peter Grun, the thing that hasn't come clear to me is the value of the cap, there are some post where he says that a value of 30uf is preferred over the stock 50uf because it would bring more focus, other posts are saying that the stock value of 50uf is the best, so I'm confused, witch is the best one?
    
    An other question that comes in mind is how to wire them up, i have already made some room in the new frame to house the larger components so that's not an issue, but must i retain the original serie-filter or can i just convert it to a parallel design so i can bi-amp it in the future?
    
    Here are some URLs to i business near by who has got some nice caps and coils, can you give your opinion about this components, are the suitable to use fore the smga?
    
    For caps there are two options:
    1. http://www.capsandcoils.com/shop/index.php?main_page=index&cPath=1_15
    2. This one i have left over from an older project in 47uf:
    http://www.bmm-electronics.nl/Product.asp?Product_ID=4993
    
    Coil:
    http://www.bmm-electronics.nl/Product.asp?Product_ID=4993
    
    
    

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    • RE: smga crossover components - ian.weitzel@btconnect.com 15:06:09 04/03/08 (0)
      In Reply to: RE: smga crossover components posted by badduh@hotmail.com on April 03, 2008 at 04:09:57

      
      Okay, you're starting to get away from me here. My intention was to do a simple upgrade of the crossover components without going crazy cost-wise, and without doing endless hours of research into capacitor / inductance types, manufacturers and values - I wanted to spend my time listening to music rather than fixing speakers.
      
      I had owned my SMGas from new, bought in 1987 and so the crossover upgrade was done at the same time as fixing the delaminated wires. I have a degree in engineering, but I have little knowledge of the more esoteric areas of electronics and I struggle to read a circuit diagram. What I can and did do was to look at the actual crossover itself. This I can read and it was obvious to me that if I removed the fuse from the circuit I could also remove the resistor in parallel with it (it's there so the tweeter doesn't go open circuit when the fuse blows and thus still presents a load to the amplifier) and consequently quite a lot of the wiring too. I wasn't in a position to experiment with different values of capacitance and inductance and just replicated the original values, 0.78mH inductance and 50μF capacitance, using as I said before, Solen cap and Sledgehammer inductor. However, as you will have gathered from searching this forum, opinions are many and varied and there are no "right" answers. It's just the usual hi-fi law of diminishing returns as you travel up the cost axis of the graph.
      
      Regarding the caps you mentioned, claritycaps are made in the UK by ICW. The PX variety are their middle range and are broadly equivalent to Ansars - they make a better range - the SA - which by all accounts are very good, although expensive and also very large - some of the higher values look like coffee mugs, which again can raise issues with mounting them. A fellow countryman of mine, Andy Evans, was very taken by claritycaps and did an analysis of them in this forum some years ago. I've put the link at the bottom of this post - if it doesn't work then do a search on Andy Evans SMGa, should find it.
      
      As far as inductors go, as I say I've been very happy with the sledgehammers. The only other ones I have direct experience of are Solen "perfect lay" which are air-cored but use heavy gauge wire so have a low DCR which I think is a significant element of the bass response of a magneplanar speaker. I looked at the web page you gave but as none of the items have a brand name it's impossible for me to comment. Have a look at the Madisound website www.madisound.com and also the IPL website in the UK www.iplacoustics.co.uk - IPL are a respected kit speaker manufacturer and their crossover components are used by a lot of diy speaker builders in the UK.
      
      I did look through Peter Gunn's postings regarding changing the capacitor value. Two things became apparent - i) it would seem that PG found that some music was improved and some was made worse with a 30μF cap, which would not seem to me to be a ringing endorsement and ii) some of the details of the components used and their values are now missing - the links don't work and information about the XO is no longer on PG's website. It may well be that now PG has gone commercial with his design he now regards the XO details as proprietary information - (which if it is the case I think is fair enough) so I think you'll need to mail him for details. Or else I just lost the thread. I seem to recall that he uses a foil inductor - again ferociously expensive.
      
      I used point to point wiring where possible, wired with QED silver-plated speaker cable where not, silver-soldered all joints, minimised the number of internal connections and replaced the rather nasty steel banana sockets with decent gold-plated binding posts. Compared with the stock speakers these changes have to make a significant improvement on their own.
      
      And that's really all I have to say on the subject. I can't help with bi-wiring as my XO knowledge doesn't stretch that far and in any case I'm not really a believer in it for Maggies. To conclude I would say that "just do it" is a useful maxim, and don't forget that it really is about the music - something I'm always having to remind myself.
      

      • http://db.audioasylum.com/cgi/m.mpl?forum=mug&n=26487&highlight=SMGa+Ansar&r=&session=   (Open in New Window)

      
      

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    • It's Gunn not Grun - Peter Gunn 14:28:41 04/03/08 (4)
      In Reply to: RE: smga crossover components posted by badduh@hotmail.com on April 03, 2008 at 04:09:57

      I really need to have Mart delete those very old, very misleading posts.
      
      For the SMGa use 50uf as follows:
      
      2 x 22uf obbligato caps
      1 x 6uf dynamicap
      
      Inductor
      
      1 x 12 gaugue alpha core .78 mh
      
      Sonic craft will custom wind this value for you.
      
      Bi-amping is not advised. This XO is the best because it makes the driver a unified whole again. By bi amping (or bi wiring) you defeat the entire purpose of that. It is not only un-necessary, it won't sound as good. (in any event 2 average amps were never the equal of one good one anyway)
      
      If you can't fit the parts inside (and you can't) just nail a box together out of pine and use that. If you can't even manage that, many craft stores now sell pre made boxes to paint. See if you can find something suitable that way.
      
      If you need my wiring schematic just email me and I'll send it to you.
      
      Good luck
      
      

      
      It's all about the music...
      
      

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      • RE: It's Gunn not Grun - badduh@hotmail.com 01:57:32 04/06/08 (0)
        In Reply to: RE: It's Gunn not Grun posted by Peter Gunn on April 03, 2008 at 14:28:41

        Peter sorry fore spelling Grun instead of Gunn, my mistake, sorry
        
        Is this the correct type cap you mentioning "Obbligato Premium Film Oil Cap"?
        I haven't found any dynamicaps yet, could i use a Obligato fore the 6 uf as well?
        

        • Obbligato Premium Film Oil Cap at ebay   (Open in New Window)

        
        

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      • RE: It's Gunn not Grun - badduh 01:52:58 04/06/08 (1)
        In Reply to: RE: It's Gunn not Grun posted by Peter Gunn on April 03, 2008 at 14:28:41

        Is this the correct type cap you mentioning "Obbligato Premium Film Oil Cap"?
        I haven't found any dynamicaps yet, could i use a Obligato fore the 6 uf as well?
        

        • Obbligato Premium Film Oil Cap at ebay   (Open in New Window)

        
        

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        • RE: It's Gunn not Grun - Peter Gunn 06:54:44 04/06/08 (0)
          In Reply to: RE: It's Gunn not Grun posted by badduh on April 06, 2008 at 01:52:58

          Yes that is them.
          
          Just go to the audio asylum "home" page where the categories are listed. Below that is a list of audio dealers, there you will find DIY hi-fi who sells the obbligatos, and sonic craft and parts connexion where you can get everything else
          
          And yes, you can use a 6uf obbligato in place of the dynamicap, but it will not sound even nearly as good. The design is meant the way it is, any change will alter the sound a lot, and for the worse.
          
          

          
          It's all about the music...
          
          

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      • RE: It's Gunn not Grun - ian.weitzel@btconnect.com 15:17:40 04/03/08 (0)
        In Reply to: RE: It's Gunn not Grun posted by Peter Gunn on April 03, 2008 at 14:28:41

        Well, there you are. I spend an hour grinding out a reply and PG has done the work for you in the meantime. Clearly not regarded as proprietary information then. I'd do what he says if I were you.
        
        

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• RE: smga crossover components - ACE_Vagi@yahoo.com 08:59:04 04/02/08 (0)
  In Reply to: RE: smga crossover components posted by badduh on April 02, 2008 at 08:22:07

  You can get the larger coils de-wound to the correct value with some brands (like north creek) otherwise going for the highwer value is the best option.
  
  Apparently foil coils are better for the tweeter coils and thick wire coils for bass panels - but I'll let you know once I get my mods completed to my 2.6R's. See my other post for details on what I'm doing at the moment.
  
  Re: Cap values - Check out Paco's 1.6 mods page. It's got schematics for many maggie models on there so you might find what you're looking for.
  
  
  

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