mrsimontibbs Posted March 25, 2022 Report Share Posted March 25, 2022 Hi. I just got a 3A midrange online, the earliest version, as a replacement, and the magnet is off-center. After hooking it up, it sounds maybe muffled and not as bright as the other one. So questions: 1. Could it be repaired? It “works” but not ideal. Is it definitely the magnet affecting the sound, or could it be something else? 2. What would cause that? Would it have been manufactured that way, or damaged, maybe in shipping? I had to enlarge the wood opening to get it to fit flush, so I can’t imagine how it was seated in the original speaker. I looked around online, but most examples and repairs of off-center magnets were on woofers. Thanks for any help! Ted Quote Link to comment Share on other sites More sharing options...
RoyC Posted March 25, 2022 Report Share Posted March 25, 2022 16 minutes ago, mrsimontibbs said: Hi. I just got a 3A midrange online, the earliest version, as a replacement, and the magnet is off-center. After hooking it up, it sounds maybe muffled and not as bright as the other one. So questions: 1. Could it be repaired? It “works” but not ideal. Is it definitely the magnet affecting the sound, or could it be something else? 2. What would cause that? Would it have been manufactured that way, or damaged, maybe in shipping? I had to enlarge the wood opening to get it to fit flush, so I can’t imagine how it was seated in the original speaker. I looked around online, but most examples and repairs of off-center magnets were on woofers. Thanks for any help! Ted Are you referring to an AR-3a or AR-3 midrange? An off-center magnet is not typical of any iteration of 3a mid, and having to enlarge the cabinet hole wouldn't be required unless you have a much later replacement mid...and if it is one of these, an off-center magnet is not at all likely. Photos will be necessary. Roy Quote Link to comment Share on other sites More sharing options...
Aadams Posted March 25, 2022 Report Share Posted March 25, 2022 9 hours ago, mrsimontibbs said: 2. What would cause that? Would it have been manufactured that way, or damaged, maybe in shipping? I had to enlarge the wood opening to get it to fit flush, so I can’t imagine how it was seated in the original speaker. I speculate the unit was damaged in shipment or the seller reattached the magnet before shipping. I had the same thing happen on my last ebay speaker shipment several years ago. A 58s cabinet took a big hit in transit that broke the glue joint and separated the magnet from the baffle mounted diaphragm. The magnet could be reattached using just the strong magnetic force, slid into mechanical alignment and appear to be properly installed but would only make a muffled sound. I think it would require some specialized equipment and knowledge to restore it to proper operation. I purchased a replacement but still have the broken one JIC. Adams Quote Link to comment Share on other sites More sharing options...
mrsimontibbs Posted March 26, 2022 Author Report Share Posted March 26, 2022 Thanks for the replies. Here are some pics. It matches my original AR 3A from the front anyway. There are no markings on back. You can see the magnet peeking out from the side. It’s possible the glue (and fingerprint) are not 50+ years old, so maybe someone did re-glue this. Quote Link to comment Share on other sites More sharing options...
RoyC Posted March 26, 2022 Report Share Posted March 26, 2022 4 hours ago, mrsimontibbs said: Thanks for the replies. Here are some pics. It matches my original AR 3A from the front anyway. There are no markings on back. You can see the magnet peeking out from the side. It’s possible the glue (and fingerprint) are not 50+ years old, so maybe someone did re-glue this. The mid in your photo is the earliest version of the AR-3a mid. The magnet was indeed glued to the plastic face plate, and the dome/voice coil assembly was glued to the underside of the (typically warped) plastic face plate. It is not uncommon for the magnet to become separated, or to literally fall off into the cabinet. I believe you are correct in the assumption that someone tried to repair it when this occurred. When the magnet becomes completely disconnected, it is nearly impossible to repair without resulting in a misaligned/rubbing voice coil. There is also no AR model equipped with this type of mid, including the earlier AR-3, which would require a modification to the cabinet hole for your mid to fit. The magnet on your specimen must really be out of whack for it not to drop in place. I'm also puzzled by the chewed up screw holes. It has obviously been through some very tough times. I have repaired a fair number of mids for forum members, as well as Ebay's "Vintage_AR", and from here it seems this one has reached the end of the line. An assortment of AR mids of this type can be found on pages 29 and 30 in the "Restoring the AR-3a" guide in the forum Library. I'm not sure what Aadams was referring to, but the glue construction described above was discontinued with the introduction of the back-wired version of the mid in the mid 70's, a number of years before the introduction of the AR-58. Screws were then used to connect the face plate to the magnet, and can be seen in photos on page 30. Roy Quote Link to comment Share on other sites More sharing options...
Aadams Posted March 26, 2022 Report Share Posted March 26, 2022 10 hours ago, RoyC said: I'm not sure what Aadams was referring to, but the glue construction described above was discontinued with the introduction of the back-wired version of the mid in the mid 70's, a number of years before the introduction of the AR-58. Screws were then used to connect the face plate to the magnet, and can be seen in photos on page 30. Here you are Roy. I had to go into my Junk archives. On examination the photos show the driver faceplate is screwed to the magnet faceplate which is glued to the magnet. The glued front and back plates of the magnet would not be noticed in a proper mechanical disassembly but thanks to ebay deeper insights are available into how a 200044-0 mid was actually assembled. Quote Link to comment Share on other sites More sharing options...
RoyC Posted March 26, 2022 Report Share Posted March 26, 2022 Thanks for the clarification and photos, Frank. Although I have seen more than a few of the magnets of front-wired mids become dislodged from the face plate I have never seen that happen to the magnet itself. To clarify a bit more for thread viewers, I added a photo of the same later style mid showing the areas we are discussing. The yellow X shows where a common separation occurs between the glued-on face plate of the earlier version mid...which was later resolved by screwing the face plate to the top of the magnet. The red X shows the issue Aadams ran across in a later mid, where the magnet assembly came apart. In either case, mrsimontibbes is not likely to salvage the mid in his photos. Roy Quote Link to comment Share on other sites More sharing options...
mrsimontibbs Posted March 27, 2022 Author Report Share Posted March 27, 2022 Thanks all for the updates. The seller agreed to refund me the price and let me keep the off-center mid instead of shipping back. So we don’t exactly know the story behind mine and I’m still on the lookout for a suitable front-wired replacement. I’ve been trying to find the early version to match, but they seem to be too rare. But now I know to inspect the magnet! Quote Link to comment Share on other sites More sharing options...
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