Bigsmurf, thank you but I'm set on the woofer. Do have a question, how do you unshift the magnet?
Juan
Advice on Fixin' New to Me EPI 100s
- Thread starter JJCalvillo
- Start date
Bigsmurf, thank you but I'm set on the woofer. Do have a question, how do you unshift the magnet?
Juan
bigx5murf
Super Member
push it around until the voice coil no longer rubs. The square magnet ones are just a bad design. Shipping it will most likely cause the magnet to shift.
Ha, I didn't know Barkeeper's Friend had oxalic acid in it. So basically a kind of wood bleach anyway. Well, whatever works for you! 
Maybe a dumb question, but once you have it in position, how does it stay in place?
Glue. Lots of people like the got glue gun for that job.
Bad glue is why it moved in the first place.
Tested the one original woofer I have on hand with a battery and it comes out w/correct polarity, and in when reversed. So, that's good.
It doesn't make a rubbing noise, just sort of a flapping from the cone, I believe because there's no surround.
It doesn't make a rubbing noise, just sort of a flapping from the cone, I believe because there's no surround.
Last edited:
So Epoxy?
10uF is all you need to know, I've used the Dayton film caps with success, although honestly the 100s in the kitchen are still wearing their original caps as they don't sound like they need it near as bad as some other speakers that have gone through my hands. If these are to be long term keepers I would definitely suggest going with some sort of film cap as NPEs have a finite lifespan.
Are you in Windsor, or generally south of Detroit?
Boto
Curmudgeon In Training
I have used the Dayton 1% caps in some Genesis and EPI rebuilds. They sound great. I have also used Human new crossovers in an EPI 100 and 240. They caps they supplied also sound great.
RTally
Speaker addict
I assume luvvinvinyl means hot glue gun.
Don't use hot glue to secure magnets. Hot glue does not have sufficient shear strength nor sufficient tensile strength to hold the magnet in place and prevent future shifting. Not to mention that hot glue does not adhere very well to large metal pieces without those pieces being preheated (or at a high ambient temperature). The metal is a heat sink that cools the hot glue before it can adequately adhere to the surfaces.
An epoxy is adequate for securing the magnet together and to the basket. For a working driver, applying epoxy around the joints is usually adequate to prevent shifting.
There should be a bunch of magnet-shift repair threads at AK. Search 'magnet shift' with the quotes or similar phrases. I have not fixed one myself and only learned about it after replacing an EPI woofer that was frozen in place, probably from a shifted magnet.
Easier said than done as the magnet wants to close the gap. I had to make a jig sort of like a Christmas tree stand that used like 5/16ths bolts to align the magnet while the basket was fastened to the base.
Once aligned, I could back them off, apply some thinned JB Weld to the magnet, and reassemble and align it.
Try pushing it a bit once you break it loose and you'll see what you're up against.
Well hell, now you've done it, lol. I sent Juan a woofer on the cheap, and I have that box packed as good as I can. Let's hope he doesn't have to worry about magnet shift just yet.
Hang in there, bud. We'll get you thru this resto, and that wood is looking better and better. Get it as good as you can, and don't sweat a small imperfection.
Thanks again for the woofer and your help. Once the speakers are singing, I'll readdress the 1 top with the stain. It isn't hideous now, but the rest of the cabinets are really nice. Could always just re-veneer the top and stain/oil to match.
Gotta get these speakers together, the Dual 1241 I'm calling hummingbird, is driving me nuts.
Last edited:
I think shipping a driver attached to a speaker cabinet is probably more likely to result in magnet shift when it's dropped than just wrapping up a woofer by itself. The reason being that the basket is fixed to the cabinet, and if a shear force is applied (dropping on any of the 4 sides besides front or back), the basket basically can't move but the magnet isn't attached to anything but the basket so it can be knocked loose. Seems like it should take a much bigger impact to make that happen when the woofer is not screwed to a large relatively immovable object. It will just bounce around a bit in its packaging.
Just my opinion from thinking about the physics of it.
Just my opinion from thinking about the physics of it.
Tox, you are probably right. I had a 24-70 lens attached to a body in a camera bag. The camera was supported on both sides of the lens but there was a gap between the end of the lens and the bottom of the bag. A short drop (1 ft.) was all it took to separate the lens mount from the rest of the lens. I was amazed, as it was a Canon L and supposed to be able to take some bumping. Had there been padding against the end of the lens, no problem. I'm sure the woofer Tim is sending will be fine.
How do you know if a magnet has shifted? I've done the battery test on both woofers and they move the direction they are supposed to with the battery normal and switched.