Speaker repair/rebuild questions

C

Craig Hauber

Sophomore
Jan 20, 2011
242
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18
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Between Williston ND and Plentywood MT
www.mondaksound.com
I'm just stabbing in the dark here that someone may know some of these DIY repair answers.

1)Does anybody have a good source for reconing parts?
I have a hobby of restoring antique radios, speakers and backline and would like to rebuild some speakers. Need shims, glues and generic cones and spiders.
Would also like to get started on more current speaker reconing too, figured the parts could work just as well for ancient speakers as well as more recent stuff

2)What do you use to dissolve existing glues on cones. Would like to re-use some coils and spiders as I doubt they are replaceable.

3)What do you use to seal the cloth accordion-type surrounds? I notice they don't hold air when you put them together fresh out of the cone-kit.

4)I have some really old speakers (50's-60's) that have always-sticky goo on the cloth surrounds and some are dried out and cracking, what do you replace that goo with to make it sticky and pliable again?

5) were ancient tube car radio field-coils battery voltage or something higher from the vibrator circuit. Were they part of the power supply like in home radios. (I'm fixing one up that I can't find a schematic for and someone cut all the wires before I got it and trying to guess how it all goes together :-)

Thanks for any help
 
Re: Speaker repair/rebuild questions

I was a reconer for quite a while and did a lot of custom/old special recones.

There are A TON of different various parts and there is no "generic" parts-simply because they are all special sizes.

For those types of repairs I used Waldom parts-I don't know if they are still around. They don't sell to the public (or didn't) so you had to be set up as a dealer.

MEK is good for cleaning most speakers. The problem is it will soften old parts-so they won't be as strong as they used to be.

Orange County Speaker sells a number of various speaker glues/sealers etc

I don't know what that "sticky goo" was-but it was used on a good number of drivers. I would use the white surround sealer that you can get from Orange County Speaker.

I have no idea on the question about the car field coil speakers. I did recone MANY old jukebox speakers that were field coils. The coil was in the power supply-like home radios.
 
Re: Speaker repair/rebuild questions

Craig Hauber said:
5) were ancient tube car radio field-coils battery voltage or something higher from the vibrator circuit. Were they part of the power supply like in home radios. (I'm fixing one up that I can't find a schematic for and someone cut all the wires before I got it and trying to guess how it all goes together :-)

Thanks for any help
Click to expand...
DC voltage through a speaker's field coil provides the magnetic field for the speaker.
AFAIK, the DC is from the battery, not elsewhere. Many old tube car radios are 6 volt, not 12, so the field coil impedance would differ between the two.

There are some old tube radio forums with people familiar with these kinds of "projects", but you will need brand names and photos to get information.
 
Re: Speaker repair/rebuild questions

Thanks John,

Out of that rather extensive catalog of adhesives, what product is ideal for cone to coil, spider to coil and cone/spider to frame? Or is there a single product that's good for all of those uses?
-in other words, what do you use?:)~:-)~:smile:

John Halliburton said:
Speaker Parts Voice Coils Speaker Repair Kits - MWA Speaker Parts, Inc.

IIR, they have lots of bits and bobs for older drivers like you are describing.

CP Moyen here in the Chicago area is a well known supplier of adhesives and treatments for the loudspeaker industry:

C.P. Moyen Co. Manufacturer of Adhesives, Coatings and Epoxies

Best regards,

John
Click to expand...
 
Re: Speaker repair/rebuild questions

Craig Hauber said:
Thanks John,

Out of that rather extensive catalog of adhesives, what product is ideal for cone to coil, spider to coil and cone/spider to frame? Or is there a single product that's good for all of those uses?
-in other words, what do you use?:)~:-)~:smile:
Click to expand...

It depends. You'll need to contact them and see if they still have a brochure or white paper on descriptions of their adhesives for the loudspeaker industry. I get anymore with industrial companies that put up a web page that is little more than a basic line card.

A lot of the front surrounds/basket, spider/basket glue ups use the white PVA based glue. Also useful for front gasket/surround/basket gluing.

Voice coil formers to baskets typically can be a couple of different adhesives. The red one, or the black one. ;>)

The red one is a solvent based adhesive, the black one is an epoxy, IIRC. Been a while since used them.

Best regards,

John
 
Re: Speaker repair/rebuild questions

Art Welter said:
There are some old tube radio forums with people familiar with these kinds of "projects", but you will need brand names and photos to get information.
Click to expand...

I've been all over the web and no forums or mailing list come close to the quality of suggestions and the overall "signal to noise ratio" of this forum and that "other one" we all came from. I'll at least ask here for a sound gearhead subject even if it's slightly off topic.
-For one reason my head really starts to hurt when over at DIYaudio.com and this one helps restore me afterwords :-)

Can you believe that searching for field-coil actually brings up forum posts and articles by audiophiles attempting to build their own in that quest for the ultimate "high end"?
They are also the types that pull the back off old alnico comp drivers, turn them around and attach that to a horn -with no phase plug! and think that sounds truer and more accurate?

I'm of the opinion that the loudspeaker industry over the last 80 years has strived for bettering themselves yet they never have gone back to field-coils so there must be a reason for that.

I'm only interested for the sake of historical reasons and the fact that we've restored every other aspect of the cars, why not the original radio too. (And since then have discovered the radios were aftermarket by motorola and not original to the car anyways)

Still interesting though, exploring 6VDC-powered mobile tube electronics.
 
Re: Speaker repair/rebuild questions

Craig Hauber said:
-For one reason my head really starts to hurt when over at DIYaudio.com and this one helps restore me afterwords :-)

Can you believe that searching for field-coil actually brings up forum posts and articles by audiophiles attempting to build their own in that quest for the ultimate "high end"?
Click to expand...

I'm with you on the first part.

The field coil speaker that guy in Norway is building is incredible.
 
Re: Speaker repair/rebuild questions

And +1 on MWA speaker parts. They have the worlds most extensive collection. And they wind voice coils special on request.
 
Re: Speaker repair/rebuild questions

Jack Arnott said:
And +1 on MWA speaker parts. They have the worlds most extensive collection. And they wind voice coils special on request.
Click to expand...

Dear all,
I want to buy some voice coil from MWA to re-cone my speaker, I contacted to the MWA by email request from MWA website for my order (about 20 pcs voice coil), but they do not sell in public.
Would you like to suggest me where can I buy voice coil from MWA ?
Last year , I had a MWA voice coil from my friend give me, and I re-cone one of my speaker, the sound is very good.
Thank you very much.
 
Re: Speaker repair/rebuild questions

Craig Hauber said:
I'm of the opinion that the loudspeaker industry over the last 80 years has strived for bettering themselves yet they never have gone back to field-coils so there must be a reason for that.
Click to expand...

That DIY field coil is incredible. Have not checked in on that in a while.
The best sounding speaker I have ever heard was field coil. And it was limited to about 12k on the high end. Two way system with two horns, crossed at 350hz.

The draw back to field coil is cost. Twice as much power needed, and twice as much heat to dissipate. So not practical for live use. There are other drawbacks too. The system I heard was "priced" at $75K, but that was more a thought than a marketing plan. They only have the one, and never sold it.

Think of it as the difference between a dynamic mic, and an electret condenser. Same principle, in reverse. The sound board provides the power, instead of a magnet as in a dynamic. Same difference in sound. With a magnet, the flux density changes with the power band. (Less so with alnico, but alnico is very expensive anymore, and other political reasons too deep to go into.) With field coil the flux density is much more stable, and so the sound is more refined.
 
Re: Speaker repair/rebuild questions

FieldCoil Adventure said:
Dear all,
I want to buy some voice coil from MWA to re-cone my speaker, I contacted to the MWA by email request from MWA website for my order (about 20 pcs voice coil), but they do not sell in public.
Would you like to suggest me where can I buy voice coil from MWA ?
Last year , I had a MWA voice coil from my friend give me, and I re-cone one of my speaker, the sound is very good.
Thank you very much.
Click to expand...


MWA has about 600 dealers. They should be able to direct you to the one closest to you. If not, try contacting your local re cone place and see if they are a MWA customer.
 
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