So, im reconing a 3015lf thts been blown for about 6months now. It was reconed by a guy locally before that, and suffered thermal failure after about 10 gigs (wired in parralel with 2 other 3015lfs with original cones/coils that didn blow)
Im wondering if maybe he set the voice coil at the wrong height? The scorch marks on it are not very similar othe oher drivers ive reconed. Ive attached a pic.
Should i: recone and put te voice coil as the same height as my blown one. Put it higher, or put it lower?
Thanks guys
Im wondering if maybe he set the voice coil at the wrong height? The scorch marks on it are not very similar othe oher drivers ive reconed. Ive attached a pic.
Should i: recone and put te voice coil as the same height as my blown one. Put it higher, or put it lower?
Thanks guys
Attachments
1) Yes, the voice coil was at the wrong height.
2) Yes, if you want to burn another voice coil just like the one shown.
3) Center the voice coil in the magnetic gap exactly like the original drivers.
Yeahhh. I wish i had an original driver to inspect... But alas i dont.
Hope someone with 3015 experience can chime in but thank you for confirming my suspicions. As soon as i pulled that coil i KNEW something was up an its only the 5th coil (2nd toasted one) that ive ever pulled
Hope someone with 3015 experience can chime in but thank you for confirming my suspicions. As soon as i pulled that coil i KNEW something was up an its only the 5th coil (2nd toasted one) that ive ever pulled
The numbers can be obtained from datasheet -- length of VC & top plate thickness.
So you can calculate the overhang. Use flash light on the side and you may see how much does the VC go beyond the gap. (without the dust cap in place, of course)
And be careful the center pole peice is often slightly longer -- higher than top plate. I'm not sure if it's the case of this particular woofer, but it can be obviously seen and measured with the cone assembly removed anyway. Just remember to take this factor into the calculation.
Good luck. 🙂
So you can calculate the overhang. Use flash light on the side and you may see how much does the VC go beyond the gap. (without the dust cap in place, of course)
And be careful the center pole peice is often slightly longer -- higher than top plate. I'm not sure if it's the case of this particular woofer, but it can be obviously seen and measured with the cone assembly removed anyway. Just remember to take this factor into the calculation.
Good luck. 🙂
could I assume xmech height as a possible distance from backplate? lol.
the pole piece is actually shorter than the rest of the top plate.
the pole piece is actually shorter than the rest of the top plate.
HTML:
If you don't have fish paper use a business card. Cut an "L" in one side slip it in and pull the lip tight. Pull it up to touch and then mark the top edge with a sharp pencil. Then using a marker on the voice coil indicate where the plate should be when it is mounted. Use shims to hold it in place while gluing up the spider.
I would also add ferrofluid to increase power handling.
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According to the datasheet, the gap height= 9.27mm, Xmax= 9.6mm.
So you may check the (burned) VC on hand to see if its length is 28.47mm or so.
If those numbers are fitted with one another, then it's OK to take Xmax (9.6mm) as the overhang.
By the photo (and the proportion to that healthy-looking thumb), I'd guess it's pretty much there.
🙂
So you may check the (burned) VC on hand to see if its length is 28.47mm or so.
If those numbers are fitted with one another, then it's OK to take Xmax (9.6mm) as the overhang.
By the photo (and the proportion to that healthy-looking thumb), I'd guess it's pretty much there.
🙂
FML.
Just went to set vc in a dry fit. Pull it out of box. Measure vc length. 22mm. WRONG coil. Supplier says that the whole shipment must have had wring coils from eminence....
Reallllllly wanted to us this cab sunday night.
Just went to set vc in a dry fit. Pull it out of box. Measure vc length. 22mm. WRONG coil. Supplier says that the whole shipment must have had wring coils from eminence....
Reallllllly wanted to us this cab sunday night.
Which completely explains what happened. Your reconer probably put it in at the 'correct' height for the LF, which would put it off center and cause it to heat up, distort, rectify, and all sorts of other nonsense.
I'm surprised you wouldn't have noticed the extra distortion and compression from the get-go. The box would have sounded weak.
I'm surprised you wouldn't have noticed the extra distortion and compression from the get-go. The box would have sounded weak.
wg ski, the burnt up coil that I just pulled IS the correct coil for the 3015lf.
the coil that was shipped to me this week IS NOT the correct coil, its about 5 to 7 mm shorter than the burnt up coil I just pulled.
The box *did* sound weak in the 10 hours of play I put into it before it died. much more harmonic distortion, even at low drive levels.
the coil that was shipped to me this week IS NOT the correct coil, its about 5 to 7 mm shorter than the burnt up coil I just pulled.
The box *did* sound weak in the 10 hours of play I put into it before it died. much more harmonic distortion, even at low drive levels.
So the dead VC had been grossly misplaced.
No matter which one you get, its (extra) length must be evenly split above and below the gap height.
FWIW and if you want to use it tomorrow, place it so its top (I´m talking the winding length, not the form length) is (22-9.27)/2=6.35mm (1/4") above the plate surface.
The speaker will work very well (definitely better than the badly reconed one), slightly less depth, slightly higher efficiency.
Not bad at all.
Don´t worry about the polepiece being some 1mm longer than plain flush , it does not mean you´ll have to raise the VC to compensate because it´s there for another purpose: to make magnetic flux slightly more symmetrical on top.
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