Speaker reconing

[Diablo]

CTS speaker reconed with Weber heavier paper cone (18 grams) and 3 inch paper dustcap.

[J M Fahey]

Diablo, thanks a lot !!
It's very useful to me.
It was very interesting seeing and analyzing the different options.
Speaker making is similar to nylon string lutherie, *everything* you do changes final sound a lot.
1) I was somewhat surprised (although I should keep Ampeg's "style" in mind) to see straight cones, non-ribbed ones used for guitar.
That gives you "punch" but not brightness or "attack" .
I would expect to see those cones in a Jazz oriented guitar amp.
The aluminum form voice coils are what was most popular in high power speakers way back then (early 70's); they were later displaced by Kapton.
Epoxy gluing matches that "higher power" idea, even if losing some brightness.
I will ask you for one extra picture if possible: the voice coil to cone union, taken from the front side, showing the "glue ring" and how the VC thin wires meet the flexible cord.
Make that two: a picture of the front plate/polepiece gap, if you still have one open.
If not, don't worry, this has already been *very* useful to me.
2) The Weber cone is what I expected from them: thin, light, 22 ribs, *very* American.
Very bright and punchy.
3) I was surprised by the VC they sent you.
It's *excellent* but won't stand much more than 25 W (we're talking mean dangerous "Guitar" watts, not "audio/HiFi" watts ).
It looks like paper, but very probably it's Nomex.
Sound will be bright and airy.
They can be glued with Cyanoacrilate, anyway Nomex will not carry heat to that joint.
You have basically re-built a "Twin speaker", blackface era, and like the originals, two of them won't stand a Twin full blast for a long time.
Four of them will stand your V4, a Plexi, and similar heads with no trouble.
4) The heavy, 8 ribs cone, will not be so bright at all, and won't cut through as much as the others.
5) What's important is that now you are becoming self-sufficient , speaker wise, and can try, if you wish, "exotic" combinations or just repair classic speakers to original spec.
Congratulations.

[Diablo]

CTS original glue joint of cone to VC. A section of the original dustcap remains. Tough epoxy glue.

[Diablo]

CTS original glue joint.

[Diablo]

Magnet gap.

[Diablo]

Tinsel wire and VC lead wire joint.

[Diablo]

A point of clarification - the Weber light cone and the original CTS heavier cone are both 22 ribs. The 3rd photo from the top shows the original CTS speaker and cone intact, except for a Weber dustcap I added during a prior attempt to fix the voice coil rub. I think the rub was due to the spider being too flexible from age or perhaps the spider to base glue joint was loose. As to the power capacity of the voice coils, the V4 is 100 watts, and anytime I used to turn the amp up I always had two speaker cabinets - eight speakers. These days I use the amp at home and have pulled two output tubes for half power and only use one speaker cabinet. Weber has a good variety of cones and VCs, and I really didn't think too much about the selection of parts. Their speaker technician offered several different cones, and I just grabbed two styles to try 'em out. Thanks for all the encouragement and help JM.

Here's a few links for Weber speaker parts and some good info on the mechanics:

https://taweber.powweb.com/parts.htm
http://www.webervst.com/sptalk.html

[J M Fahey]

OK, thanks.

[Steve Conner]

Diablo, you said that your new speakers sounded a bit harsh. Try breaking them in, they might improve after a few hours of blasting.

[Diablo]

I'll have to send the wife out shopping during the speaker blast breaking in party.

[Tom Phillips]

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[Tom Phillips]

A new spammer, shanda, has found the forum.

[trevorus]

Diablo, you said that your new speakers sounded a bit harsh. Try breaking them in, they might improve after a few hours of blasting.

I found this to be true with some WGS speakers I bought new. I thought they sounded terrible until I broke them in. Then they became the epitome of tone to me.

I also have some old AlNiCo speakers my grandpa gave me that were both in rough shape. I am going to try the one, and if it goes well, I will be doing another. They have some small voice coils though! Anyone know what the specs on a Celestion Blue is? I may see if I can get close with this setup.

[J M Fahey]

Well, probably not turn them into Celestion Blues, you don't have their *huge* magnetic system, and used 44mm (1 3/4") voice coils, but you can certainly recone them to "NOS-Vintage" specs if you get the parts and use the vintage technology.
You'll need the very thin and light original cones or a close equivalent, and a light, short voice coil, wound on paper.
If not available, Kapton is next in line.
It will lose some sparkle compared to the original one, but will stand much more power.
*Maybe* Weber has a Nomex version, almost as good as paper.
You must use what used to be called "speaker cement", the nitrocellulose type.
I buy a can of "base" nitrocellulose car paint, no pigment added, and just let it open in the Sun a couple days until it thickens to "honey".
You'll need to let the speaker dry for a few days, we are not talking epoxy or super glue here.
Good luck.

[trevorus]

Yeah, I wouldn't be opposed to losing a bit of sparkle at all. Besides the constant background buzz of voice coil rub, they were quite bright. Of course, the smaller magnet will keep the thing on the brighter side, but I'm all for making it slightly beefier, toning down the highs a bit, and making it stand some power. I'll be building either a bassman clone or something similar soon, so these will likely be running through these old alnicos.