Did my 1st ever speaker re-cone!

[tubeswell]

Weber 15F150. Was a 30W version, but the 30W coil had overheated and was rubbing on the magnet. Installed a 50W recone kit for the same model (which uses the same cone, basket, magnet, and spider, but a different coil). Brian Spane at Weber is really helpful with recone parts lists. Took me 5 hours. The next one will be faster LoL

[Enzo]

Way to go. That is one thing I never tried in my career, I just figured I'd screw it up completely.

[tubeswell]

Just tried it at 1/2 power on one of my home-brewed T-bolts. Quite bluesy sounding. Will wait a couple more days for the glue to really harden before I thrash it.

[Tom Phillips]

I was surprised that the spider flange surface that glues to the basket is so narrow. I suppose that the wider flange used in the past is not necessary because modern glues are better.

[g1]

What did you do for ventilation, or did you work outside?

[J M Fahey]

Weber 15F150. Was a 30W version, but the 30W coil had overheated and was rubbing on the magnet. Installed a 50W recone kit for the same model (which uses the same cone, basket and magnet, but a different spider and coil). Brian Spane at Weber is really helpful with recone parts lists. Took me 5 hours. The next one will be faster LoL

Congratulations, excellent job

Pictures are very useful too so somebody attempting this has some kind of "map".

If possible, post here Weber parts numbers you used, so next time somebody else already knows what to order, afaik Wever does not supply kits per se, but you mix and match what you need.

The old voice coil bubbled because itīs wound on NOMEX, which is a synthetic paper.
As light and sounds practically the same as regular paper, stands higher temperature than cellulose, only problem is that commonly available type is "calendered", meaning itīs passed through two very hot polished steel rolers, they leave surface very smooth but a problem (for us) is that it seals all pores, yet some air is trapped inside.
When voice coil overheats, hot air expands, can NOT get out (itīs sealed inside) and so pushes walls apart: it bubbles big time as can be seen there.
I tried to get un calendered NOMEX but minimum order is 10 tons or so

I *guess* your new VC is wound on Kapton: shiny translucid plastic sheet, dark orange colored.

Not easy to see because itīs wrapped in white or brown paper almost to the edge to help glueing to cone, is that so?

Congratulations again.

[J M Fahey]

I was surprised that the spider flange surface that glues to the basket is so narrow. I suppose that the wider flange used in the past is not necessary because modern glues are better.

I guess Weber did not have the proper spider at the time and supplied a cut down one, because what they had was way too tall, so original flange got stored in the circular basket.
You can get out with it if you apply a *generous* bead of glue all around it.

In both cases I was surprised at the very small diameter spiders, specially for a 15" speaker , I would have used at least 1" wider diameter.

Only explanation is that they assume it will *always* be used in a small open back combo and want to limit cone travel the brute force way.

@ g1 : for a single speaker adhesive fumes are not much, unless you do it in a bedroom at 3 AM and "honey" is sleeping a couple feet away .... "nothing" compared to tolexing a cabinet or spray painting a guitar or chassis.

[Tom Phillips]

Pete - Regarding your photo #5 named "New spider and 50W coil glued in" ... I don't see any trace of glue showing between the spider & the basket. Does that mean that the voice coil was glued into the spider because they were supplied as separate parts and that the spider is not yet glued to the basket?

Juan - Thanks for the great explanation of the parts & procedures.

Tom

[tubeswell]

Pete - Regarding your photo #5 named "New spider and 50W coil glued in" ... I don't see any trace of glue showing between the spider & the basket. Does that mean that the voice coil was glued into the spider because they were supplied as separate parts and that the spider is not yet glued to the basket?

Tom

If you squint you should be able to see the barely detectable traces of superglue contact adhesive around the base of the spider where it attaches to the basket

[tubeswell]

I guess Weber did not have the proper spider at the time and supplied a cut down one, because what they had was way too tall, so original flange got stored in the circular basket.
You can get out with it if you apply a *generous* bead of glue all around it.

The speaker recone guy at Weber specified that in the parts list and it matches the spider that came with the original.

The recone parts (from this site) for the 15F150 are:

Coil - vc1515H_8 (H is for 'heavy' - has a kapton former)
Cone -WC15N (same cone used for many of the weber 15" guitar speakers - quite a stiff cone - reasonably thick molded paper.
Spider - SN1
Dustcap - DCQ
Gasket - G15
tinsel wire (You need 2 pieces for this job)


I've previously also gotten recone parts information for the Sig12 and 12A125A speakers, as follows:

Cone - the WC12A goes on the Sig12A-S and the 12A125-A. It has to be trimmed to fit the 12A125-A. (by gently burring the VC-end hole in the cone slightly wider with the back of your thumb nail)

The other parts are

Sig12A-S

vc1015-8 (for an 8 ohm sig12, this coil also has kapton former, which is rated at 25w
WC12A
SR1
DCQ
G12
tinsel wire


12A125-A

vc1250h_8 (8 ohm, 30 watt coil)
WC12A
SQ2
DCQ
G12
tinsel wire


Brian can be contacted here: brian@tedweber.com

[tubeswell]

If possible, post here Weber parts numbers you used, so next time somebody else already knows what to order, afaik Wever does not supply kits per se, but you mix and match what you need.

(I posted these in another reply to one of your other comments in this thread just now)

The old voice coil bubbled because itīs wound on NOMEX, which is a synthetic paper.
As light and sounds practically the same as regular paper, stands higher temperature than cellulose, only problem is that commonly available type is "calendered", meaning itīs passed through two very hot polished steel rolers, they leave surface very smooth but a problem (for us) is that it seals all pores, yet some air is trapped inside.
When voice coil overheats, hot air expands, can NOT get out (itīs sealed inside) and so pushes walls apart: it bubbles big time as can be seen there.

Yeah I figured that was the case. It sounded like shit, Kind of all distorted, weeby and gutless as you tried to crank it up. Sounds all better again now.

I *guess* your new VC is wound on Kapton: shiny translucid plastic sheet, dark orange colored.

Not easy to see because itīs wrapped in white or brown paper almost to the edge to help glueing to cone, is that so?

Correct. For the shim on this I experimented and found that a strip of regular printing paper cut to the just shy of the length of 2 x the pole piece circumference produced the perfect snug fit. (Thats the blue paper in the pictures.)

[The Dude]

Nice work! Just a little tip. What I often do is put a speaker of the same size upside down on top of the speaker being reconed as a weight to hold the cone and gasket(s) in place until the glue dries. It'll save you some clamping.

[Jazz P Bass]

A piece of writing paper as a shim.

That's what .003" x 2 gap?

So it doesn't take much to make coil rub, huh?

[J M Fahey]

A piece of writing paper as a shim.

That's what .003" x 2 gap?

So it doesn't take much to make coil rub, huh?

Slightly more, about .004" separation between VC former and pole piece in this case.

And yes, space must be held to a minimum because airspace (same as vacuum) is a terrible path for magnetic force: air or vacuum permeability is 1 by definition while iron/steel goes from 100 to 5000 , depending on purity, alloy, heat treatment, etc.

The point is that iron differences pale compared to the roadblock created by even a *short* path through air, so "wasted" gap space must be held to the absolute minimum which is still functional.

Thatīs why those car audio monstrosities have huge magnets, stacked 2, 3 or even 4 high ... yet have abysmal efficiency: they have gaps you can get your finger in.

A great part of the good sound attributed to Alnico speakers, must in fact be attributed to very tight gaps and close tolerances held way back then.
I have a dead 12" Jensen speaker, dated 1946 and pulled from a 16mm projector labelled US Navy, go figure, where I still couldnīt wind a voice coil that fits comfortably.

It either scratches on the inside or if **slightly** larger scratches on the outside
Speaker is painted Navy grey and sports a large cylinder Alnico magnet similar to P12N .
Well, not *that* wide, but thatīs the idea

[The Dude]

Agreed, Juan. It's also a part of why the Peavey Black Widow speakers are less efficient than most. They had to make that gap pretty large to be able to offer a field replaceable basket.

Edit: I should add that I have nothing against BW speakers. Very affordable, easily repairable, and sturdy.