Rewinding loudspeaker coil
 

Or admiration of the art of louspeaker making.
46V DC on 8 ohm 10 inch speaker, didn't last long, going o/c.
Decided to try rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid connections. Heating
the frame with a hot air gun and pushing the periphery of the cone with a
well used and rounded wooden kitchen spatula, separated cleanly from the
gummy glue.
Put in spacers to stretch the inner dust diaphragm and hot air gun heating
unglued the periphery of that corrugated disc.
I didn't expect to see what was inside. A burnt mass of wire and the
innermost end of the penetrating lacquered paper cylinder neatly burnt off
in a perfect ring.
Gap in magnet about 66 thou, paper cylinder about 5 thou thick and 2 layers
of about 2 x 30 turns of 6 thou wire (originally). I don't fancy trying to
rewind on a small paper cylinder and fixing to the remnant all with such
XY&Z precision to clear that 2x 25thou slot gap in the magnet.
For the next time anyone know of a WWW site explaining the jigs, paper
lacqering process, wattage/wire guage/turns etc ?.
Its amazing such cloth and paper art, more than technology, can take the
punishment.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

Rewinding loudspeaker coil
 

On Wed, 19 Apr 2006 07:43:50 +0100, "n cook"
wrote:

Or admiration of the art of louspeaker making.
46V DC on 8 ohm 10 inch speaker, didn't last long, going o/c.
Decided to try rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid connections. Heating
the frame with a hot air gun and pushing the periphery of the cone with a
well used and rounded wooden kitchen spatula, separated cleanly from the
gummy glue.
Put in spacers to stretch the inner dust diaphragm and hot air gun heating
unglued the periphery of that corrugated disc.
I didn't expect to see what was inside. A burnt mass of wire and the
innermost end of the penetrating lacquered paper cylinder neatly burnt off
in a perfect ring.
Gap in magnet about 66 thou, paper cylinder about 5 thou thick and 2 layers
of about 2 x 30 turns of 6 thou wire (originally). I don't fancy trying to
rewind on a small paper cylinder and fixing to the remnant all with such
XY&Z precision to clear that 2x 25thou slot gap in the magnet.
For the next time anyone know of a WWW site explaining the jigs, paper
lacqering process, wattage/wire guage/turns etc ?.
Its amazing such cloth and paper art, more than technology, can take the
punishment.

Not a task I would try, although I believe some have done it.

If the speaker manufacturer is reputable/well known you may be able to
buy a replacement cone/voice coil assembly. This is the standard
method used by speaker repairers and it is so much simpler and can be
very cost effective. The next solution is to buy a new driver.....

Rewinding loudspeaker coil
 

n cook spake thus:

Or admiration of the art of louspeaker making.
46V DC on 8 ohm 10 inch speaker, didn't last long, going o/c.
Decided to try rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid connections. Heating
the frame with a hot air gun and pushing the periphery of the cone with a
well used and rounded wooden kitchen spatula, separated cleanly from the
gummy glue.
Put in spacers to stretch the inner dust diaphragm and hot air gun heating
unglued the periphery of that corrugated disc.
I didn't expect to see what was inside. A burnt mass of wire and the
innermost end of the penetrating lacquered paper cylinder neatly burnt off
in a perfect ring.
Gap in magnet about 66 thou, paper cylinder about 5 thou thick and 2 layers
of about 2 x 30 turns of 6 thou wire (originally). I don't fancy trying to
rewind on a small paper cylinder and fixing to the remnant all with such
XY&Z precision to clear that 2x 25thou slot gap in the magnet.

Possibly impertinent question: wouldn't a guy want to use a mandrel of
some kind to wind the coil on? That way you wouldn't have to worry about
a flimsy paper cylinder collapsing, no? (Like maybe a turned piece of wood.)


--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists"

Rewinding loudspeaker coil
 

David Nebenzahl wrote in message
.com...
n cook spake thus:

Or admiration of the art of louspeaker making.
46V DC on 8 ohm 10 inch speaker, didn't last long, going o/c.
Decided to try rewinding as I've never tried it before. Found a clean
way to
remove the cone from the frame. Desoldered the braid connections.
Heating
the frame with a hot air gun and pushing the periphery of the cone with
a
well used and rounded wooden kitchen spatula, separated cleanly from the
gummy glue.
Put in spacers to stretch the inner dust diaphragm and hot air gun
heating
unglued the periphery of that corrugated disc.
I didn't expect to see what was inside. A burnt mass of wire and the
innermost end of the penetrating lacquered paper cylinder neatly burnt
off
in a perfect ring.
Gap in magnet about 66 thou, paper cylinder about 5 thou thick and 2
layers
of about 2 x 30 turns of 6 thou wire (originally). I don't fancy trying
to
rewind on a small paper cylinder and fixing to the remnant all with such
XY&Z precision to clear that 2x 25thou slot gap in the magnet.

Possibly impertinent question: wouldn't a guy want to use a mandrel of
some kind to wind the coil on? That way you wouldn't have to worry about
a flimsy paper cylinder collapsing, no? (Like maybe a turned piece of
wood.)


--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists"

But the cylinder is just glued to the cone, take it off any mandrel and
there is nothing to stop it going just slightly oval.
Temperature changes, humidity changes, self weight in use etc and I only
come across a coil/cylinder rubbing in the magnet housing after abuse.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

Rewinding loudspeaker coil
 

You might have some luck by posting this over in
rec.antiques.radio+phono. I believe that some folks there have rewound
a voice coil.

Bill
~~~~~~~~~~~~~~~~~~~`

n cook wrote:

Or admiration of the art of louspeaker making.
46V DC on 8 ohm 10 inch speaker, didn't last long, going o/c.
Decided to try rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid connections. Heating
the frame with a hot air gun and pushing the periphery of the cone with a
well used and rounded wooden kitchen spatula, separated cleanly from the
gummy glue.
Put in spacers to stretch the inner dust diaphragm and hot air gun heating
unglued the periphery of that corrugated disc.
I didn't expect to see what was inside. A burnt mass of wire and the
innermost end of the penetrating lacquered paper cylinder neatly burnt off
in a perfect ring.
Gap in magnet about 66 thou, paper cylinder about 5 thou thick and 2 layers
of about 2 x 30 turns of 6 thou wire (originally). I don't fancy trying to
rewind on a small paper cylinder and fixing to the remnant all with such
XY&Z precision to clear that 2x 25thou slot gap in the magnet.
For the next time anyone know of a WWW site explaining the jigs, paper
lacqering process, wattage/wire guage/turns etc ?.
Its amazing such cloth and paper art, more than technology, can take the
punishment.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

Rewinding loudspeaker coil
 

n cook spake thus:

David Nebenzahl wrote in message
.com...

n cook spake thus:

Or admiration of the art of louspeaker making. 46V DC on 8 ohm 10
inch speaker, didn't last long, going o/c. Decided to try
rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid
connections.

Heating the frame with a hot air gun and pushing the periphery of
the cone with a well used and rounded wooden kitchen spatula,
separated cleanly from the gummy glue. Put in spacers to stretch
the inner dust diaphragm and hot air gun heating unglued the
periphery of that corrugated disc. I didn't expect to see what
was inside. A burnt mass of wire and the innermost end of the
penetrating lacquered paper cylinder neatly burnt off in a
perfect ring.

Gap in magnet about 66 thou, paper cylinder about 5 thou thick
and 2 layers of about 2 x 30 turns of 6 thou wire (originally). I
don't fancy trying to rewind on a small paper cylinder and fixing
to the remnant all with such XY&Z precision to clear that 2x
25thou slot gap in the magnet.

Possibly impertinent question: wouldn't a guy want to use a mandrel
of some kind to wind the coil on? That way you wouldn't have to
worry about a flimsy paper cylinder collapsing, no? (Like maybe a
turned piece of wood.)

But the cylinder is just glued to the cone, take it off any mandrel and
there is nothing to stop it going just slightly oval.
Temperature changes, humidity changes, self weight in use etc and I only
come across a coil/cylinder rubbing in the magnet housing after abuse.

OK, then how about lacquering the assembly after winding; shouldn't this
help it keep its shape? I think this is what speaker mfrs. do.


--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists"

Rewinding loudspeaker coil
 

David Nebenzahl wrote in message
.com...
n cook spake thus:

David Nebenzahl wrote in message
.com...

n cook spake thus:

Or admiration of the art of louspeaker making. 46V DC on 8 ohm 10
inch speaker, didn't last long, going o/c. Decided to try
rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid
connections.

Heating the frame with a hot air gun and pushing the periphery of
the cone with a well used and rounded wooden kitchen spatula,
separated cleanly from the gummy glue. Put in spacers to stretch
the inner dust diaphragm and hot air gun heating unglued the
periphery of that corrugated disc. I didn't expect to see what
was inside. A burnt mass of wire and the innermost end of the
penetrating lacquered paper cylinder neatly burnt off in a
perfect ring.

Gap in magnet about 66 thou, paper cylinder about 5 thou thick
and 2 layers of about 2 x 30 turns of 6 thou wire (originally). I
don't fancy trying to rewind on a small paper cylinder and fixing
to the remnant all with such XY&Z precision to clear that 2x
25thou slot gap in the magnet.

Possibly impertinent question: wouldn't a guy want to use a mandrel
of some kind to wind the coil on? That way you wouldn't have to
worry about a flimsy paper cylinder collapsing, no? (Like maybe a
turned piece of wood.)

But the cylinder is just glued to the cone, take it off any mandrel and
there is nothing to stop it going just slightly oval.
Temperature changes, humidity changes, self weight in use etc and I
only
come across a coil/cylinder rubbing in the magnet housing after abuse.

OK, then how about lacquering the assembly after winding; shouldn't this
help it keep its shape? I think this is what speaker mfrs. do.


--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists

I've been doing some measuring and looks as though such speakers use a sort
of air bearing/ ground effect.
Inside diameter of the slot in the magnet something a bit less than 1.502 in
so probably 1.5 inches. Inside diameter of the paper cylinder that goes
inside the magnet gap about 1.65 inches so with a gap width of bit greater
than 66 thou and paper plus double thickness coil of 15 thou means the wire
cannot touch the outer diameter of the magnet gap. And I just cannot believe
that in all operational circumstances that the inside of the paper cylinder
can never touch the inside surface of the slot with only 7 thou of
clearance. A silicone treatment to the inside surface of the paper cylinder
would make sense, anyone know whether it is used ?
Knowing that I might have a go gluing a new bit of cylinder and new coil to
the existing remnant of cylinder as there is plenty of external room for
excess glue/binding.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

Rewinding loudspeaker coil
 

In article , "n cook" wrote:
David Nebenzahl wrote in message
s.com...
n cook spake thus:

David Nebenzahl wrote in message
.com...

n cook spake thus:

Or admiration of the art of louspeaker making. 46V DC on 8 ohm 10
inch speaker, didn't last long, going o/c. Decided to try
rewinding as I've never tried it before. Found a clean way to
remove the cone from the frame. Desoldered the braid
connections.

Heating the frame with a hot air gun and pushing the periphery of
the cone with a well used and rounded wooden kitchen spatula,
separated cleanly from the gummy glue. Put in spacers to stretch
the inner dust diaphragm and hot air gun heating unglued the
periphery of that corrugated disc. I didn't expect to see what
was inside. A burnt mass of wire and the innermost end of the
penetrating lacquered paper cylinder neatly burnt off in a
perfect ring.

Gap in magnet about 66 thou, paper cylinder about 5 thou thick
and 2 layers of about 2 x 30 turns of 6 thou wire (originally). I
don't fancy trying to rewind on a small paper cylinder and fixing
to the remnant all with such XY&Z precision to clear that 2x
25thou slot gap in the magnet.

Possibly impertinent question: wouldn't a guy want to use a mandrel
of some kind to wind the coil on? That way you wouldn't have to
worry about a flimsy paper cylinder collapsing, no? (Like maybe a
turned piece of wood.)

But the cylinder is just glued to the cone, take it off any mandrel and
there is nothing to stop it going just slightly oval.
Temperature changes, humidity changes, self weight in use etc and I
only
come across a coil/cylinder rubbing in the magnet housing after abuse.

OK, then how about lacquering the assembly after winding; shouldn't this
help it keep its shape? I think this is what speaker mfrs. do.


--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists

I've been doing some measuring and looks as though such speakers use a sort
of air bearing/ ground effect.
Inside diameter of the slot in the magnet something a bit less than 1.502 in
so probably 1.5 inches. Inside diameter of the paper cylinder that goes
inside the magnet gap about 1.65 inches so with a gap width of bit greater
than 66 thou and paper plus double thickness coil of 15 thou means the wire
cannot touch the outer diameter of the magnet gap. And I just cannot believe
that in all operational circumstances that the inside of the paper cylinder
can never touch the inside surface of the slot with only 7 thou of
clearance. A silicone treatment to the inside surface of the paper cylinder
would make sense, anyone know whether it is used ?
Knowing that I might have a go gluing a new bit of cylinder and new coil to
the existing remnant of cylinder as there is plenty of external room for
excess glue/binding.


Your going to have to insert shims in there anyway to reattach the cone
so its linned up. I don't know if ferro fluid is silicone based, probably.

greg

Rewinding loudspeaker coil
 

But the cylinder is just glued to the cone, take it off any mandrel and
there is nothing to stop it going just slightly oval.
Temperature changes, humidity changes, self weight in use etc and I only
come across a coil/cylinder rubbing in the magnet housing after abuse.


If you wind the coil with a mandrel inside of the paper cylinder, and
bond the coil to the cylinder with something ( adhesive? laquer?
polyurethane?) when you're done, I would think that the wire would add
significant rigidity to the otherwise flimsy paper.

If you're still worried about deformation, leave the mandrel in the coil
while you glue the cylinder to the cone. Then there is no way it will go
out of round, short of gross mechanical injury.

Just a thought.

Pete

Rewinding loudspeaker coil
 

H. P. Friedrichs wrote:

But the cylinder is just glued to the cone, take it off any mandrel and
there is nothing to stop it going just slightly oval.
Temperature changes, humidity changes, self weight in use etc and I only
come across a coil/cylinder rubbing in the magnet housing after abuse.



If you wind the coil with a mandrel inside of the paper cylinder, and
bond the coil to the cylinder with something ( adhesive? laquer?
polyurethane?) when you're done, I would think that the wire would add
significant rigidity to the otherwise flimsy paper.

If you're still worried about deformation, leave the mandrel in the coil
while you glue the cylinder to the cone. Then there is no way it will go
out of round, short of gross mechanical injury.

Just a thought.

Hi...

Used to do this way back in the olden days (just shortly after
they invented sunshine :) so let me throw in my 2 cents in the
hope it may be helpful.

First, though, never ever created voice coils themselves. On a rare
occasion replaced one. Much more often replaced cones that had
been penetrated by little fingers, tools, or just dried out and
cracked.

A thought, if I may? Don't think I'd glue the winding to the
form; might rather consider shellacing it in place, while the
whole thing is still on it's solid form. Use a spray can; that
way you'll stiffen the paper form as well.

Don't think it matters much (if at all) if the form does go
slightly out of round while it's "in hand" What has to be done
is find pieces of paper that will fit perfectly between the
magnet and the newly wound coil and it's form. Has to be just
right - tight enough to firmly hold the coil in place, yet able
to be pulled out without damaging the coil or form.
(remember that the coil has to not only be centered, but also
temporarily hold the coil at the proper height - so that it
won't hit bottom or come free of the magnetic field when the
cone moves)

So, experiment with paper weights, find ones that can fit just
snuggly enough. Cut yourself a number of pieces, 'bout 3 or
4 inches long, 1/4 inch wide. Drop the coil in alone, look
with a flashlight and magnifying glass to see what it looks like
bottomed. Take it out again, insert it with the paper shims all
around so that half of the free space you just saw is now free
again with the shims in place.

Now glue down the outer circumference of the cone, and spot glue
the voice coil to the cone at 4 equidistant spots between the shims.
When this glue is firmly set, remove 4 more shims at 90 degree
seperation, tack the newly freed spots. Keep this up until the
shims are all out, and the coil is firmly held all around its
perimeter.

Install the dust cap, and you're done :)

Take care.

Ken