G'day all, I have had a rather unfortunate failure of two midbass units in a pair of Usher S-520 bookshelf speakers. I notice my drivers have a different fly-lead arrangement to other versions of the drivers and I think this construction may have contributed to the failure of the drivers. Can anyone with more driver design experience than I have shed any light on this or has anyone else had the same misfortune?
The voice-coils of the drivers are shiny and clean - no scorched spots. I cannot see any signs of overpowering and no deformations from rubbing or "poling". I removed the insulation in fact from the magnet wire as it exited the wound portion of the voice-coil toward the spider and tested from those points and in fact the voice-coil proper measures fine! 😡
So it the failure has occurred along the flexible "ribbons".. and in my drivers these are fused into the spider. When I move the spider by hand I notice that there is a definite position in the spider, close to the voice-coil fastening points at the center of the driver that is stationary and immediately next to that there is movement.. at this point I believe is a failure point waiting to happen with respect to the fly-leads and I wonder if anyone else has had this issue. Very frustrating since it has happened to *both* my speakers. Granted, it was during a loud passage with some substantial bass notes.. but as I said - none of the usual signs of excessive dissipation or excursion - ie poling or torn suspensions or spider - the flyleads just seem to have chosen identical moments to give up. I can't help but feeling this could be a manufacturing issue.
If any of you chaps feel like offering your experiences/opinions I'd be pleased to listen!
All the best from sunny Australia!
p.s. If anyone knows a source for replacement drivers I'd be pleased to know that too. I've just sent a mail off to Usher Taiwan but a good deal of that site is in Taiwanese (fair enough too!) so I'm not necessarily holding big expectations at this point. Oh, mine do appear to be the most recent incarnations of the speakers (later version crossover with improved capacitors and slightly attenuated HF output as compared to the older version).
The voice-coils of the drivers are shiny and clean - no scorched spots. I cannot see any signs of overpowering and no deformations from rubbing or "poling". I removed the insulation in fact from the magnet wire as it exited the wound portion of the voice-coil toward the spider and tested from those points and in fact the voice-coil proper measures fine! 😡
So it the failure has occurred along the flexible "ribbons".. and in my drivers these are fused into the spider. When I move the spider by hand I notice that there is a definite position in the spider, close to the voice-coil fastening points at the center of the driver that is stationary and immediately next to that there is movement.. at this point I believe is a failure point waiting to happen with respect to the fly-leads and I wonder if anyone else has had this issue. Very frustrating since it has happened to *both* my speakers. Granted, it was during a loud passage with some substantial bass notes.. but as I said - none of the usual signs of excessive dissipation or excursion - ie poling or torn suspensions or spider - the flyleads just seem to have chosen identical moments to give up. I can't help but feeling this could be a manufacturing issue.
If any of you chaps feel like offering your experiences/opinions I'd be pleased to listen!
All the best from sunny Australia!
p.s. If anyone knows a source for replacement drivers I'd be pleased to know that too. I've just sent a mail off to Usher Taiwan but a good deal of that site is in Taiwanese (fair enough too!) so I'm not necessarily holding big expectations at this point. Oh, mine do appear to be the most recent incarnations of the speakers (later version crossover with improved capacitors and slightly attenuated HF output as compared to the older version).
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