The values I have used in calculating XO component values in various XO simulations is 4ohms for each driver.
Regards,
Andy
Also, I think there is more bass wire.
Check here SMGa buzzing, and a loose wire - roycej - Planar Speaker Asylum
Something is missing from the center
At least in mine SMGs, there 2 loops of wire, even in the center. I don't know if there are differences in the lengths of the wires though.
Check here SMGa buzzing, and a loose wire - roycej - Planar Speaker Asylum
Something is missing from the center
At least in mine SMGs, there 2 loops of wire, even in the center. I don't know if there are differences in the lengths of the wires though.
Back again. Somewhat predicatably, the tweeter in my other speaker stopped working this weekend. Again it was open circuit, with a fault traced to a breakage somewhere on the diaphragm. Frustrating, but thank goodness repairs are, if not trivial, straightforward for the most part, especially the tweeter section. Out with the repair kit, acetone and Super77 spray glue, and by Sunday evening, the lovely music was playing again.
If you plan on doing this, do yourself a big favour and buy a proper aluminium solder kit with the right flux. Worth every penny!
Now also, the obsessive compulsive side of me is satisfied that both speakers have had equal treatment
Ed
If you plan on doing this, do yourself a big favour and buy a proper aluminium solder kit with the right flux. Worth every penny!
Now also, the obsessive compulsive side of me is satisfied that both speakers have had equal treatment
Ed
3 Pairs of SMGa's For Sale -- UK Only
Hi All,
I have been following this thread since the start.
Now I have come to the comclusion that I do not (and will not) have time to repair my SMGa's.
So I have 3 pars of these fantastic speakers -- all in poor condition having been in storage for some years.
Anyone want to make me an offer for 1 or all ???
I also think that I have a repair kit ( aluminium wire - original Magnepan)
PM me
Thanks.
Kevin
Hi All,
I have been following this thread since the start.
Now I have come to the comclusion that I do not (and will not) have time to repair my SMGa's.
So I have 3 pars of these fantastic speakers -- all in poor condition having been in storage for some years.
Anyone want to make me an offer for 1 or all ???
I also think that I have a repair kit ( aluminium wire - original Magnepan)
PM me
Thanks.
Kevin
Last edited:
That's a shame Kevin.
From my experience, the job can be done comfortably with about a day per speaker. No jig is required, just a suitable form to make the turns at the end of each straight run of wire. This can even be the right sized pen, drill bit etc. etc.
The essential part is to make good notes on the wire layout, take pictures etc. so there is no guessing at the rewire stage.
Cheers,
Ed
From my experience, the job can be done comfortably with about a day per speaker. No jig is required, just a suitable form to make the turns at the end of each straight run of wire. This can even be the right sized pen, drill bit etc. etc.
The essential part is to make good notes on the wire layout, take pictures etc. so there is no guessing at the rewire stage.
Cheers,
Ed
Quick question for you folks regarding wire replacement on these speakers.
I have a pair of SMG-b that I am just about to start on.
Why is it that some of the loops of wire are double loops whereas other loops are single wires?
And..
do the double loop of wire complicate laying down new wire when attempting the repair?
I'm assuming the SMG's and SMG-a's are the same in this regard as the SMG-b's that I am dealing about to repair.
The picture posted here shows what I am referring to.
OK, folks thank you very much and best regards.
Curt
I have a pair of SMG-b that I am just about to start on.
Why is it that some of the loops of wire are double loops whereas other loops are single wires?
And..
do the double loop of wire complicate laying down new wire when attempting the repair?
I'm assuming the SMG's and SMG-a's are the same in this regard as the SMG-b's that I am dealing about to repair.
The picture posted here shows what I am referring to.
OK, folks thank you very much and best regards.
Curt
Attachments
Hi Curt,
The double loops are important for a couple of reasons. For a start, the total length of wire is important, to get the appropriate DC resistance of the "voice coil" if this changes, the load on the amp, and balance with the tweeter will not be per the design.
Secondly, the extra pass through the magnetic path will act to increase the drive on the diaphragm, achieving the specified sensitivity. This is all a careful balance that I'm sure Magnepan spent a lot of time working out empirically.
As to layup, it doesn't complicate things too much. Mark the vertical positions of the two sets of end loops before you start - a guide on the edge of the panel frame is really helpful here. Then choose a couple of round forms (pens, drill bits, wood dowels etc.) that match the curves needed at each turn, and use these to help form the bend as you lay out the wire. Be extra careful not to kink the wire, it is alumium, and very easily fatigued. Careful handling, though, will avoid trouble.
I first looked at this and thought "No way to tackle this without a jig" But it turns out that care with hand layout of the wires can provide excellent results if one takes time and care.
I hope that is helpful.
Ed
The double loops are important for a couple of reasons. For a start, the total length of wire is important, to get the appropriate DC resistance of the "voice coil" if this changes, the load on the amp, and balance with the tweeter will not be per the design.
Secondly, the extra pass through the magnetic path will act to increase the drive on the diaphragm, achieving the specified sensitivity. This is all a careful balance that I'm sure Magnepan spent a lot of time working out empirically.
As to layup, it doesn't complicate things too much. Mark the vertical positions of the two sets of end loops before you start - a guide on the edge of the panel frame is really helpful here. Then choose a couple of round forms (pens, drill bits, wood dowels etc.) that match the curves needed at each turn, and use these to help form the bend as you lay out the wire. Be extra careful not to kink the wire, it is alumium, and very easily fatigued. Careful handling, though, will avoid trouble.
I first looked at this and thought "No way to tackle this without a jig" But it turns out that care with hand layout of the wires can provide excellent results if one takes time and care.
I hope that is helpful.
Ed
another thing to notice they do double loops near the side ways of the membrane, where the membane is more limited by the spacer/tension to get higher excursion out of these spots then normally would be possible.
making good pictures or draw layout is crucial as someone stated already , its verry easy to forget how the wires went
making good pictures or draw layout is crucial as someone stated already , its verry easy to forget how the wires went
Hey Everyone,
thanks so much for the very detailed info.
Even though there are some dual loops of wire, it all sounds like its do-able.
Just got to document
I too was thinking this job is going to need a jig.
But I guess the set up characteristics of the glue make it possible
to get the wires laid down correctly. So I will try it that way.
Now all I have to do is get down to the store and load up on cotton balls and acetone
Thnx again and take care
Curt
thanks so much for the very detailed info.
Even though there are some dual loops of wire, it all sounds like its do-able.
Just got to document
I too was thinking this job is going to need a jig.
But I guess the set up characteristics of the glue make it possible
to get the wires laid down correctly. So I will try it that way.
Now all I have to do is get down to the store and load up on cotton balls and acetone
Thnx again and take care
Curt
No, you don't use magnets to hold the wire down. What you should do is connect a 12v battery to the ends of the wire loops (with a series resistor to limit the current flowing, to 0.5-1a). This holds the wire against the magnets (ie. the mylar).
By all means also use, say, 15mmD washers on top of the wire loops at the top & bottom of the mylar. The magnets 'grab' these and hold the wires down.
Re. making a jig - I suggest it's easier to lay the wire on the glued mylar and then wrap it round, say, a pencil to (wrap around, to) get the curves at the top and bottom. You should be able to lay the wires straight along the gaps, between the magnet strips.
Regards,
Andy
Last edited:
Just a screen shot of the current setup of my original 17μf smg, full-razored. Although not the best looking, all this mass and forces have improved the rigidity of this incredible speaker in a very cheap way.
An externally hosted image should be here but it was not working when we last tested it.
Glad I found this! I picked up a pair of MG IIc's that I'm getting ready to re-wire
Glad I found this! I just picked up a pair of MG IIc that need the treble sections re-wired. However, just to see what they sounded like I hooked them up. To my surprise they worked for the full range and really sounded pretty good!
I thought for sure I'd have an open circuit on at lease on of the treble panels, but I got a full spectrum response on a 20-20k sweep.
On closer inspection what looked to me like an open circuit had actually been a 'repair' job with some wire and scotch tape.
I will start a new thread on their restoration..
Glad I found this! I just picked up a pair of MG IIc that need the treble sections re-wired. However, just to see what they sounded like I hooked them up. To my surprise they worked for the full range and really sounded pretty good!
I thought for sure I'd have an open circuit on at lease on of the treble panels, but I got a full spectrum response on a 20-20k sweep.
On closer inspection what looked to me like an open circuit had actually been a 'repair' job with some wire and scotch tape.
I will start a new thread on their restoration..
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.