speaker repair wizzard needed

[limono]

OK !having spent all my money on EV , TAD , Lowthers I've got in my posession a pair of JBL LE8 (old rusty alnico mags) full range drivers with surrounds changed. Frankly, these are the best drivers I ever heard. Tonally, they smoked Enabled lowthers DX4's and nothing (maybe some vintage Tannoys I briefly heard years ago) comes close to my ears. There are two problems with them . Voice coils are partially shorted and both drivers measure 1.3 ,1.5 Ohm DCR . Painted aluminium dust cap was ,is, a little ringy.
Is there anybody who could for resonable (very) amount of money:
take them appart (I probably can do it ) check if the short in VC can be fixed
eventually rewind the VC (maybe even with silver wire ) ,try phase plug instead of alu dust cap (I intend to use a tweeter anyway) measure the speakers ,play with them as long as one pleases and send them back??
Regards, L

 

[Cal Weldon]

Did they look anything like this?

 

[Cal Weldon]

.

 

[limono]

Little better 🙂 I don't expect miracles ,hehe
These are first (or one of the first) LE-8 .Your fine samples are I gues LE-8T.
They do play fine on mikro Watt level .

 

[limono]

Oh , I think I know what you're thinking .Is it possible??
Regards, L

 

[Cal Weldon]

What I'm thinking is...

The price to recone made mine expendable. No one wanted to use anything but original parts and that would have cut way too far into the beer fund. I agree they are a great driver but honest to betsy these were going to cost 300USD each cone plus install and shipping. No, I gave them to charity. 😉
The dust caps on mine were attached to the top of the coil so they got that extra bit of extension. Yes they were the LE8T. Thanks for the pic of yours.

 

[limono]

OK I thought that you still have them and since the cones are trashed the coils could be reused.I know that original recone kits are $$$ (if you can get them). Well time to prepare acetone and a razor blade 😉
Best , L

 

[pinkmouse]

Well time to prepare acetone and a razor blade 😉

Try a hot air gun and palette knife first. 😉

 

[limono]

Hot air gun to loose up suspension ? It's been 20 years since I repaired a speaker and I remember we usually soaked up suspension (upper and lower) with acetone and waited overnight to loose it up . Than mandrel with thin paper around matched to voice coil diameter. Than search for magnet wire...

 

[picopos]

hey
probably was exposed to dc and if u still have a reading in impedance u r lucky as i would only open them and treat the coil...well i did it before with results ,they still work...
open them and keep posting,good luck

marco

 

[limono]

Treat the coil means paint it with varnish ??

 

[picopos]

What I'm thinking is...

The price to recone made mine expendable. No one wanted to use anything but original parts and that would have cut way too far into the beer fund.


h hh h
if nothing better to do and assuming they're really good even Cal's ones would be putted to work(they wouldn't look preety) but maybe it would be possible to have a even sound on the pair,leaving has much as possible the original materials at work...i hate to waste money h h

much respect Cal


Marco

 

[picopos]

in the lack of materials and knowledge i even used metal varnish
i think it's supposed to be something like enamel,i'm from Portugal and i know the name of the stuff as we call it there sorry about that....i think by ur description that u just need a steady hand,calm and a good eye....

 

[picopos]

but in any way each speaker has it's hard spots,

do they make any sound at all?
do u feel any disturbance in the coil if u push the cone?
u of corse dont want to break the coil on the moment of desasembling but i bet u have all that experience,if i was u i would be optimistic.....

 

[limono]

yes they play fine with beautiful tone. I really don't know what happend.I got them from a friend who replaced suspension.I think the former owner tried to play them with old deteriorated foam or had an amp problem. Funny thing is that I had them for a few months playing on the "wisper" level and although I noticed they can't take any power I thought thats normal for those speakers.

 

[picopos]

well i really have no ideia of the specs of those speakers but right know i use 20 watt speakers on a at least 50 w rms and i can pump it up no problem besides the compression of the signal(this of course depends on the program,if i wish i can also kill at least easy tweeter and midrange)but i think it's always best to have an amp with more power rated then the speaker(more headroom)i play bass and the power amp i use right now gives 1000 watt(i'll never use them) in parallel mono into a 700 watts(maximum program) speaker and the speaker was never before so more controlled loud and clear(but it's hard carring all the weight)all this to say that those speakers have to work fine loud and they seem heavy duty capable easy...use the acetone ,be delicate(that's ur babies h h h)and probably it's a matter of some days to have them filling up ur room with music....if they still give u good sound(bass and everything) it really seem's like a dry coil , i had this woofer's from a 3 way pair and one of them just got with the coil all loose inside(i didn't even try repairing) and i think it was a case of quality on the manufacter ,one still works the other dyed in the way ,no amp problem cause still today i never had a similar problem.....bla bla bla

hey do some more listening on them (go easy) try to understand whats going on inside (coil touching sides,getting wasted,or maybe that happen before and now it's not noticable besides the low impedance reading---bad suspension alignment)
hey all of what i'm saying it's based on my experience on trying to fix pairs of speakers that are worth it and maintaning they original carachter instead of reconing both with some times not similar materials and fixing them with no cost noticable,tweeters i've been lucky and put them to life again but i was very lucky also with the point were they brake...

tell us how they sound after fixed,
and,
do u have some specs???

 

[picopos]

by the way when i close a speaker i always have to take the center part in order to make sure i'm leaving the stuff well aligned,.....right now i a have an 8ohm black widow to fix in the coil area but i'm avoiding it cause the gap is so tight that i'm having trouble to solve the problem(the part that holds the coil deformed)(it sounds like overdrive but it's a mechanical noise),but in other hand these black widow i just have to order a full basket with original cone and alumnium voice coil and put the magnet of the failled one(they're prepared for that and i just need a wrench)(peavey black widow 15")

 

[limono]

Thanks for your thoughs. My speakers move freely ,no strange noises, no signs of rubbing , loose coil etc. Just both of them reads LOw DCR ~1,5Ohm instead 5.7 Ohm (or so). Lets try the heat gun. and check it out.

 

[pinkmouse]

Hot air gun to loose up suspension ? It's been 20 years since I repaired a speaker and I remember we usually soaked up suspension (upper and lower) with acetone and waited overnight to loose it up .

Acetone is certainly a viable approach to dismantling, however I've noticed it seems to soften the cone material in some speakers. The hot air gun method with a palette knife to scrape at the softening adhesive is one I always try first, just in case, before resorting to solvents. As for your DCR issue, have you tried testing T/S? They may be 4 Ohm V/Cs that just measure low on a DVM.

 

[limono]

Al ,
I thought about it but they are 50W rated speakers (AFAIK) and can't take even 2W .Never saw a dynamic speaker measuring 1.3 DCR. I used hot gun on one of them -works like a charm on a new foam replacement -thanks a bunch for the hint.Accordion lower suspension will have to be soaked up in accetone and left overnight , maybe even more but it started snowing already (can't stand this winter anymore )and I can't move on. Once I'll take cones from the baskets I'll post a picture.
L