I picked up this amp broken and cheap only because it is another DLM-4500 based amp and uses a much newer revision. I wanted to test my cloned DLM-4500 driver in as many of these different models as possible and this one has one of the newest revisions, still a DLM-4500 but no daughter board, just the house brand 28 pin control IC.
Anyhow, that is not pertinent to the question. I have the amp mostly repaired, it had been run hard with a high resistance ground connection and melted the terminal blocks along with a few other little issues.
When I took it apart I found that one of the output inductors which are wound on ferrite "bobbins" in these amps had broken at the bottom, basically leaving the large end of the bobbin glued in place with the typical black fixative, and a fairly clean break through the ferrite. I have not removed it yet, but is it possible to glue or epoxy the bobbin back together and retain similar magnetic properties? My research say tentatively that it should be okay as long as I am not missing any big pieces of ferrite. I expect it will not be seriously difficult to source a new core, but to source one that matches the stock one in anything other than size and shape might be a problem.
I suppose worst case scenario I could wind a few different cores and test inductance on each to match the factory coils... I don't intend to run this amp long term or to sell it, I just want to use it as a test bed for the cloned drivers. It only has to be good enough for testing, is it possible to epoxy or glue and get acceptable results. If so, are there any suggestions?
Thanks,
Jason
Anyhow, that is not pertinent to the question. I have the amp mostly repaired, it had been run hard with a high resistance ground connection and melted the terminal blocks along with a few other little issues.
When I took it apart I found that one of the output inductors which are wound on ferrite "bobbins" in these amps had broken at the bottom, basically leaving the large end of the bobbin glued in place with the typical black fixative, and a fairly clean break through the ferrite. I have not removed it yet, but is it possible to glue or epoxy the bobbin back together and retain similar magnetic properties? My research say tentatively that it should be okay as long as I am not missing any big pieces of ferrite. I expect it will not be seriously difficult to source a new core, but to source one that matches the stock one in anything other than size and shape might be a problem.
I suppose worst case scenario I could wind a few different cores and test inductance on each to match the factory coils... I don't intend to run this amp long term or to sell it, I just want to use it as a test bed for the cloned drivers. It only has to be good enough for testing, is it possible to epoxy or glue and get acceptable results. If so, are there any suggestions?
Thanks,
Jason
Okay, sounds good. I have some #10 nylon hardware, that was something else I had considered. I'm not 100% sure there is room for the pan head under the board. I will investigate it further. If glue is used, I was thinking just loctite 404, basically super glue. I can pop it between soft jaws of my vice to cure if epoxy would be a better choice.
As always, thank you for your assistance. It's appreciated.
Jason
As always, thank you for your assistance. It's appreciated.
Jason
When I got the bobbin of the board I found the bottom was cracked, so here is what I ended up with. I 3d printed some little cups, I gotta the bottom pieces in the cup and the inductor back together. Super glued it all and then put a plastic printed center on in the middle and heat welded it in place. Looks all good now.
Thanks!
Jason
Thanks!
Jason
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