[west]

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make coils
wound on plastic bobbins due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be susceptible. Do you think
this is a true claim and why? Perhaps Jantzen is gilding the lily?

Cordially,
west

[Peter Wieck]

west wrote:
Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make coils
wound on plastic bobbins due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be susceptible. Do you think
this is a true claim and why? Perhaps Jantzen is gilding the lily?

Please point to the source of that informaton. By your word, it simply
is not enough for legitmate comment... or legitimate enough for
comment... either way.

Peter Wieck
Wyncote, PA

[Eeyore]

Peter Wieck wrote:

west wrote:
Did you know this about plastic bobbins?
While reading a Jantzen ad

Don't they make swimsuits ?

Graham

[Eeyore]

west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make coils
wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be susceptible.

Why ?

Sounds fairly nutty to me for sure.

Graham

[Patrick Turner]

Eeyore wrote:

Peter Wieck wrote:

west wrote:
Did you know this about plastic bobbins?
While reading a Jantzen ad

Don't they make swimsuits ?

Graham

Plastic bobbins for crossover coils are notoriously bad items,
and often made using plastic that is too thin, and too soft, flimsy, and
the result of a corrupt bean counter's mind,
and A&R speakers are full of them.
Not only that, the winding isn't usually bonded together with varnish or
epoxy,
and is usually a random wound item and just taped around on completion,
and the bobbin is held
to a thin masonite board with an Aluminium stud with a steel spring clip
which is subject to the magnetic field.

But these coils are not very microphonic, certainly not as much as
some capacitors were thought to be, such as those un old JBL speakers
where
they placed the caps in sealed cardboard cylinders, and filled around
the cap
with CarlyFornia Beach Sand, a very special and rare substance only
found
on the US west coast in that lesser known seaside village discovered by
Karl Ifornia.

The village went broke when someone decided polypropylene caps were
better and cheaper.

The simple test for microphony is to have a signal present and
hammer the coils with a mallet, and if any sound is heard via the
speaker, then they are microphonic,
since wire movement is altering the inductance and slightly
amplitude/phase modulating the signal.
But chances are the sound of whacking the darn coils at the mallet is
louder than any electronic signal
is in the speaker, and must lees of an effect than whacking the cables
going into a
phono preamp, something that proves interconnects can be microphonic,
and I am sorry
to spoil all audiophile's saturday because now I have given then
something else to tear their hair out
with worry after spending a zillion bucks on gear.... :-)

Happy coil whacking!

Meanwhile, watch that goil in de Jantzen, she coulda getta me into a
lotta nice trouble...


Oh, and I like to wind all my own coils, random is OK, but I like to use
varnish so the
coil wire is adhered together, and movement is unlikely...
Then I use a brass screw and large timber washer to fix the coil to a
plywood board for the crossover;
no flimsy pcbs are to be found at TA.


Patrick Turner.

[Peter Wieck]

Patrick Turner wrote:

Stuff about poor quality-control with coil-winding.

And all of it true. True of wood, plastic, epoxy, composite, bakelite,
catalin, air and about anything else.

Crap made with crap using crap techniques will, usually, result in
crap. Inexpensive materials used with great care and proper techniques
may give excellent results. Plastic forms sufficiently substantial,
carefully made and treated properly will be just fine. And the coils
coming off them will be just fine if properly handled and treated
thereafter. Stabilzation after winding is absolutely necessary if only
to control the inevitable 'settling' effects of the wire, for lack of a
better word.

But again, there will be some who tell you that putting a NEMA 5-20R
20A @ 125V receptacle into liquid nitrogent for a specified period will
result in audible differences from your speakers.

Peter Wieck
Wyncote, PA

[west]

"west" wrote in message
news:jJAnh.301$Ul4.156@trnddc05...
Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make coils
wound on plastic bobbins due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be susceptible. Do you
think
this is a true claim and why? Perhaps Jantzen is gilding the lily?

Cordially,
west

For those who need to know: Jantzen Audio Denmark, www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line. I'm a
bit surprised that they are not recognized. Hope this helps.

Cordially,
west

[Eeyore]

west wrote:

"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make coils
wound on plastic bobbins due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be susceptible. Do you
think
this is a true claim and why? Perhaps Jantzen is gilding the lily?


For those who need to know: Jantzen Audio Denmark, www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line. I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

Graham

[Eeyore]

flipper wrote:

Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make coils
wound on plastic bobbins due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be susceptible. Do you
think this is a true claim and why? Perhaps Jantzen is gilding the lily?


For those who need to know: Jantzen Audio Denmark, www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line. I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

Graham

[west]

"Eeyore" wrote in message
...


flipper wrote:

Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make
coils
wound on plastic bobbins due to the risk of microphony." I can only
think
that perhaps coils in speaker crossovers might be susceptible. Do
you
think this is a true claim and why? Perhaps Jantzen is gilding the
lily?


For those who need to know: Jantzen Audio Denmark,
www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free
manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line.
I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

Graham

"will not make coils on plastic bobbins" means they make coils. Why are you
picking fly **** out of pepper instead of keeping the focus on another
possible cause for microphonics?
BTW: Thanks to Professor Turner for his post which was both informative and
cordial.
Cordially,
west

[Jon Yaeger]

in article kYZnh.664$8B5.578@trnddc08, west at wrote on
1/6/07 10:40 PM:


"Eeyore" wrote in message
...


flipper wrote:

Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make
coils
wound on plastic bobbins due to the risk of microphony." I can only
think
that perhaps coils in speaker crossovers might be susceptible. Do
you
think this is a true claim and why? Perhaps Jantzen is gilding the
lily?


For those who need to know: Jantzen Audio Denmark,
www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free
manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line.
I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

Graham

"will not make coils on plastic bobbins" means they make coils. Why are you
picking fly **** out of pepper instead of keeping the focus on another
possible cause for microphonics?
BTW: Thanks to Professor Turner for his post which was both informative and
cordial.
Cordially,
west




Definitions of "cordial" on the Web:

1) affable: diffusing warmth and friendliness; "an affable smile"; "an
amiable gathering"; "cordial relations"; "a cordial greeting"; "a genial
host"

2) showing warm and heartfelt friendliness; "gave us a cordial reception";
"a hearty welcome"

[Patrick Turner]

west wrote:

"Eeyore" wrote in message
...


flipper wrote:

Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make
coils
wound on plastic bobbins due to the risk of microphony." I can only
think
that perhaps coils in speaker crossovers might be susceptible. Do
you
think this is a true claim and why? Perhaps Jantzen is gilding the
lily?


For those who need to know: Jantzen Audio Denmark,
www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free
manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line.
I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

Graham

"will not make coils on plastic bobbins" means they make coils. Why are you
picking fly **** out of pepper instead of keeping the focus on another
possible cause for microphonics?
BTW: Thanks to Professor Turner for his post which was both informative and
cordial.
Cordially,
west


The gear sold by
http://www.jantzen-audio.com
looks very good. The foil wound coils look very nice for Xovers indeed,
and offer excellent performance, but its difficult for the DIYer to
build such things
because unlike magnet winding wire which is easily available the flat
foils is hard to get.
No doubt Jantzen prices will horrify the penny pinching diyer.

I would think though that neat air cored layer wound round wired coils
which are varnished and baked
would be quite blameless in sonic/technical performance.
To get low winding resistance losses the coils should have not more than
5% of the load value
which is in series with a coil, so an inductor of say 4mH in series with
say a 6 ohm woofer
for a crossover pole at 238 Hz the dcr should be 0.3ohms, and this means
using a coil
about 2 or 3 times the size of anything usually supplied in generic good
brand speakers.

Then there are ferrite cores shaped like cotton reels around which less
turns of thinner wire may be wound
to achieve the low dcr but have the same L, and who knows if these sound
better or worse, but
when in doubt, don't use iron in X-over coils, just air thankyou very
much!
Coils used in shunt situations usually don't need to have extremely low
dcr, and in fact
some effective series R in the form of dcr resistance is quite
acceptable in many cases
for a damped resonant trap or shunt L of some kind.

I make my own bobbins often with plywood cheeks cut from squares of 6mm
plywood
and drilled to take 25mm timber dowel. The dowl is cut to about 40mm
long, and
well glued to the cheeks and a 13mm hole drilled through the dowel
centre to fit
my winding lathe shaft.
I try to keep the cross section of the coil square, to ensure an
efficient coil
so dcr is minimal, and ppl should be prepared to do their own
experimenting
with wire and inductance meter.
Obviously, there is no need to bake the coil on the wooden bobbin;
the bobbin usually holds the wire firmly enough, and just soaking with
polyurethane
furniture varnish is fine and it will eventually dry and cure with air
exposure.

The completed coil is mounted on the X-over plywood components board and
the fixing can be with brass screws
through the cheek or another 12mm dowel through the centre of the coil
and through the board.
Solid, and simple, and not the result of a pea brained bean counter.

Engineering Enterprizes in Melbourne, Victoria, sell a range of plastic
bobbins
but they are all a bit flimsy, although they are a good source for
transformer
bobbins for E&I laminations.
These bobbins can also be used for crossovers and they are stiffer than
the round type bobbins.
But winding onto rectangular bobbins is a PITA for the uninitiated, and
I suggest those
who are dedicated and serious and who are equipped tool wize use the
wooden bobbin method,
or else could use flat PVC sheet and electricians PVC conduit for the
centres.
Such bulk materials are CHEAP, and very effective.

Meanwhile, one can purchase most coils wanted for speakers in the local
Jaycar stores in Oz and
perhaps WES components, but usually the dcr is dissapointingly high so I
never buy any,
and if they did have low loss coils avaiable the price would be high and
so even though
the cost of making hand made specials is higher again who cares, because
we end up with something that will last 100 years and
work perfectly.

Patrick Turner.

[Eeyore]

west wrote:

"Eeyore" wrote in message
flipper wrote:
Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make
coils
wound on plastic bobbins due to the risk of microphony." I can only
think
that perhaps coils in speaker crossovers might be susceptible. Do you

think this is a true claim and why? Perhaps Jantzen is gilding the
lily?


For those who need to know: Jantzen Audio Denmark,
www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free
manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line.
I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

"will not make coils on plastic bobbins" means they make coils.

So ?

Many companies make coils including ones I've worked ( consulted ) for.


Why are you picking fly **** out of pepper instead of keeping the focus on
another
possible cause for microphonics?

Show me a microphonic inductor and I'll show you Shangi La.

Graham

[Eeyore]

flipper wrote:

Eeyore wrote:
flipper wrote:
Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make coils
wound on plastic bobbins due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be susceptible. Do you
think this is a true claim and why? Perhaps Jantzen is gilding the lily?


For those who need to know: Jantzen Audio Denmark, www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line. I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

It's even still up there. "While reading a JANTZEN AD... they claimed
to 'NOT MAKE coils wound on..."

What's so bloody hard to figure out?

In what way does that prove that the Jantzen Co is a component manufacturer ?

I have previously *never* come across a *component manufacturer* placing an
advertisement in a magazine for the general public.


Graham

[Eeyore]

flipper wrote:

Eeyore wrote:
flipper wrote:
Eeyore wrote:
flipper wrote:
Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make
coils
wound on plastic bobbins due to the risk of microphony." I can only
think
that perhaps coils in speaker crossovers might be susceptible. Do you
think this is a true claim and why? Perhaps Jantzen is gilding the lily?


For those who need to know: Jantzen Audio Denmark,
www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free
manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line. I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

It's even still up there. "While reading a JANTZEN AD... they claimed
to 'NOT MAKE coils wound on..."

What's so bloody hard to figure out?

In what way does that prove that the Jantzen Co is a component manufacturer ?

Lordy but you can be a thick headed obstinate arguer for simply the
sake of arguing.

You see an "ad" and they "make" something. Whether it's a 'proof' or
not it's a damn good guess and I'd wager your average Joe with no axe
to grind would naturally figure as much.

Since when did any advertisement prove the company was purely a coil-winder ?


You just felt like poking a stick in his eye and are now trying to
find some way to defend poking a stick in his eye.

I'll poke a stick in your eye if that's what's required.


I have previously *never* come across a *component manufacturer* placing an
advertisement in a magazine for the general public.

Besides him not originally saying anything about where he saw the ad,
'general public', 'magazine', or whatever, not that it matters one
whit 'where' because he saw an AD from someone who MAKES something,
you must have a limited reading exposure.

Duh !

You are such a waste of space Mr Dolphin.


Graham

[Patrick Turner]

Jon Yaeger wrote:

in article kYZnh.664$8B5.578@trnddc08, west at wrote on
1/6/07 10:40 PM:


"Eeyore" wrote in message
...


flipper wrote:

Eeyore wrote:
west wrote:
"west" wrote in message

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to "not make
coils
wound on plastic bobbins due to the risk of microphony." I can only
think
that perhaps coils in speaker crossovers might be susceptible. Do
you
think this is a true claim and why? Perhaps Jantzen is gilding the
lily?


For those who need to know: Jantzen Audio Denmark,
www.jantzen-audio.com
has the aforementioned ad in "Multi Media Manufacture" a free
manufacturer's
guide to AV design & development. The ad is in the Jan/Feb 2007, p.9
magazine, highlighting their new "Audio-Z audiophile capacitor line.
I'm a
bit surprised that they are not recognized. Hope this helps.

Oh a component manufacturer / supplier !

Why didn't you say before ?

He did, quite clearly.

No he did not !

Graham

"will not make coils on plastic bobbins" means they make coils. Why are you
picking fly **** out of pepper instead of keeping the focus on another
possible cause for microphonics?
BTW: Thanks to Professor Turner for his post which was both informative and
cordial.
Cordially,
west



Definitions of "cordial" on the Web:

1) affable: diffusing warmth and friendliness; "an affable smile"; "an
amiable gathering"; "cordial relations"; "a cordial greeting"; "a genial
host"

2) showing warm and heartfelt friendliness; "gave us a cordial reception";
"a hearty welcome"

Sometimes i also like to drink that red colured codial made with
fermented grapes.

But never too much, or I can't drive home.

I always accept a cordial reception when they hand me a glass of it.

Ah, tiz the time of year to drink red cordial to be sure now.

And to gaze upon the triodes and listen to some music.

Patrick Turner.

[Eeyore]

flipper wrote:

On Sun, 07 Jan 2007 13:17:40 +0000, Eeyore
wrote:

Since when did any advertisement prove the company was purely a coil-winder ?

Since when were "component manufacturer" and "purely a coil-winder"
synonyms?

"west" mentioned neither.

Graham

[Steven Swift]

Eeyore writes:

Show me a microphonic inductor and I'll show you Shangi La.

Graham

Don't know about audio, but this is a source of spurs in RF design. You can
see them on a spectrum analyzer when your UUT is on a shake table. The coils
need to be vacuum impregnated or potted. You can also hear capacitors and
inductors in power supplies and amplifiers. I would assume that the properties
are somewhat reciprocal.

Steve.

--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA

[Eeyore]

Steven Swift wrote:

Eeyore writes:

Show me a microphonic inductor and I'll show you Shangi La.

Graham

Don't know about audio, but this is a source of spurs in RF design. You can
see them on a spectrum analyzer when your UUT is on a shake table. The coils
need to be vacuum impregnated or potted. You can also hear capacitors and
inductors in power supplies and amplifiers. I would assume that the properties
are somewhat reciprocal.

On a shaker table you don't surprise me.

Graham

[Arny Krueger]

"Eeyore" wrote in
message
west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to
"not make coils wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be
susceptible.

Why ?

Sounds fairly nutty to me for sure.

Agreed. Note that Pat Turner has to ignore the fact that coils wound on
plastic bobbins can be encapsulated in epoxy or dipped in varnish.

[Arny Krueger]

"Steven Swift" wrote in message

Eeyore writes:

Show me a microphonic inductor and I'll show you Shangi
La.

Graham

Don't know about audio,

Would you believe that there are some differences between good practice for
audio and good practice for RF?

but this is a source of spurs in RF design.

....if you ignore accepted practice.

You can see them on a spectrum analyzer when
your UUT is on a shake table.

....if you ignore accepted practice.

The coils need to be vacuum
impregnated or potted.

Or good practice followed by other means, such as using thicker wire.

You can also hear capacitors and
inductors in power supplies and amplifiers.

You can hear output transistors, as well. Moral of story, don't put them at
your sweet spot.

That was a real brain teser, wasn't it? ;-)

I would assume that the properties are somewhat reciprocal.

Logic like that will have you worrying about skin efffect in speaker cables.

[Eeyore]

Arny Krueger wrote:

"Eeyore" wrote
west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to
"not make coils wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be
susceptible.

Why ?

Sounds fairly nutty to me for sure.

Agreed. Note that Pat Turner has to ignore the fact that coils wound on
plastic bobbins can be encapsulated in epoxy or dipped in varnish.

Provided that the former material is non-magnetic it has zero influence on the
result.

Graham

[Patrick Turner]

Eeyore wrote:

Arny Krueger wrote:

"Eeyore" wrote
west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed to
"not make coils wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be
susceptible.

Why ?

Sounds fairly nutty to me for sure.

Agreed. Note that Pat Turner has to ignore the fact that coils wound on
plastic bobbins can be encapsulated in epoxy or dipped in varnish.

Did I have to ignore this? was I forced to ignore it?
By whom?

Cossover coils can be wound WITHOUT ANY BOBBIN AT ALL.
Its probably difficult for the DIYer to achieve because how do you hold
the wire
in place as you wind it and after you have wound it?
Well, that's not impossible and industry has achieved it easily and the
diyer
can wind the coil in a TEMPORARY bobbin and the wire can be lightly
varnished
by brushing it on after each layer. Alternatively epoxy can be used to
glue the windings as one proceeds. The former bobbin needs to be not
likely to
adhere to the wires during the wind up so one may have to wax it before
winding.

When the completed winding is done and the former removed from the lathe
and each half
removed from each side of the coil the total wound item can be
encapuulated in
epoxy or whatever to make a solid block with mounting holes for a brass
screw.

Many boobinless coils are merely held together with 3 or 4 plastic
cable-ties
after removal of the coil from the lathe where not even a temporary
former is used at all
and no varnish/glue either. The ties clamp the turns together in a more
or less neat
nut unlayered bundle, and this is all some makers have done in the
crossovers.

They use a blob of hot glue to attatch the coil to a PCB. All very
slapdash indeed,
and the movement of the wires during vibration would cause a change in
inductance hence phase
or amplitude modulation of any signal present.

The loose wound coil done well is not a disaster if it bundled with the
ties, or perhaps
wound around with string lashings, then dipped in whatever binding
substance one wishes to use
such as molten wax, polyurtethane varnish, epoxy, etc, as long as such
things are not
so viscous that they cannot penetrate the coil interior via natural
capilliary action.

Its not too difficult to make a 'fingered' coil holder for one's winding
lathe
to allow bundling by cable ties of a wound coil before removal of the
coil off the lathe.
You just need to be keen, practically minded, and damned determined.

But I have often made up my own timber bobbins, and endeavoured to layer
wind the coil.
Place the bobbin on the lathe, wind the turns, and no more muckinmg
around.

Neat layering means slightly less turns for a given L. L needs to be
measured as the turns go on,
and this means removal off the lathe for measurement with an inductance
meter
connected between the bared start lead of the coil and a small section
of bared wire yet to be wound on.
This could be very messy without a bobbin.
Different wire guages mean different coil dimensions and hence different
L
and its all too unreliable and difficult to always calculate with
Wheeler's Formula or whatever.
Best to wind and measure, wind and measure, but with an initial estimate
as a guide.
And taps are easy. Taps are usually necessary
because with diying speakers and the X-overs, the final L, C and R
values chosen depend on the
very much corrected values of the L,C & R initially chosen by
calculation,
but which need confirmation my careful
accoustic measurements, and in practice the final design of a X-over is
very different to the
initially calculated design.
As a diyer, one expects one's efforts to be better than what can be
purchased in the shops,
designed bt bean counters and dumbed down by the whole "process".

Most speaker X-overs are just calculated, and the results applied
without adequate
trimming of values to get the simplest LCR arrangement
but flattest speaker response that sounds the best, and simplicity means
not having to use
an absurd number of resonant traps and filters to bring the response
that extra 0.5dB
closer to best possible, which is NEVER perfectly flat, despite what
many makers may say/show in their
lie ridden data sheets/graphs.
I have tested countless mainstream speakers and have yet to see a single
pair ever
have a response within +/- 3dB between 50Hz and 15kHz at amy position of
the test microphone using
pink noise in any room. One does really well to get a speaker to give an
*average* response of
+/- 2dB across the band, where the average is the average dB of six
different mic positions
around the listening seat.

Many commercially available speakers are utter engineering jokes.
No wonder the reviewers give so many different opinions about speakers;
the response is
very different for every pair they review; all act like de-facto graphic
equalizers,
and of course, what magazine reviewer has a good bit of testing
equipment?

Not a huge number of modern made speakers have grossly microphonic coils
though.
The fashion now due to bean counters selecting the cheapest appraoch of
such hidden technology
as crossovers is for pre-formed ferrite bobbins, and wire wound on
around these
tends to remain firmly placed and is thus non microphonic.
The cost of iron bobbins must be less than many more turns of what must
be bigger diameter wire
to achieve the same L and dcr in an air cored coil.
Has anyone analysed the effect on thd/imd of iron cored coils used in
speaker x-overs?
Presumably a spiral core of GOSS, similar to what is used for say a 15VA
power tranny
could make a nice low dcr coil in series with a bass speaker.
So would the thd/imd be worse than any microphonic effects?
What is the effect of the iron core non-linearities?
Does the use of a solenoid instead of a toroid of GOSS mean
that less thd/imd occurs?

I can't help but raise more questions, as there are what seem to me to
be
greater issues involved than the perils of microphonic coils.


Provided that the former material is non-magnetic it has zero influence on the
result.

The dielectric effects would possibly also be negligible at audio F
with plastics/wood.


Graham

Patrick Turner.

[Arny Krueger]

"Eeyore" wrote in
message
Arny Krueger wrote:

"Eeyore" wrote
west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed
to "not make coils wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be
susceptible.

Why ?

Sounds fairly nutty to me for sure.

Agreed. Note that Pat Turner has to ignore the fact that
coils wound on plastic bobbins can be encapsulated in
epoxy or dipped in varnish.

Provided that the former material is non-magnetic it has
zero influence on the result.

Well, the former can be mechanically significant. Inductors can be
microphonic, but solving that problem is not unmanagably impeded by the use
of a plastic former.

[Arny Krueger]

"Patrick Turner" wrote in message

Eeyore wrote:

Arny Krueger wrote:

"Eeyore" wrote
west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed
to "not make coils wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be
susceptible.

Why ?

Sounds fairly nutty to me for sure.

Agreed. Note that Pat Turner has to ignore the fact
that coils wound on plastic bobbins can be encapsulated
in epoxy or dipped in varnish.

Did I have to ignore this? was I forced to ignore it?
By whom?

Nice job of backpedalling, Patrick.

Cossover coils can be wound WITHOUT ANY BOBBIN AT ALL.

No they can't. Coils in finished products that lack bobbins were wound on
temporary bobbins. I guess you've never been in a coil factory, Patrick.

Its probably difficult for the DIYer to achieve because
how do you hold the wire
in place as you wind it and after you have wound it?

You use a temporary bobbin, Patrick. I can tell that you never studied
machine tool design or industrial engineering and have never been in an
electrical or electronics factory.

Save your posturing for people that are poorly informed, Patrick.

[Eeyore]

Arny Krueger wrote:

"Patrick Turner" wrote in message
Eeyore wrote:
Arny Krueger wrote:
"Eeyore" wrote
west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they claimed
to "not make coils wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be
susceptible.

Why ?

Sounds fairly nutty to me for sure.

Agreed. Note that Pat Turner has to ignore the fact
that coils wound on plastic bobbins can be encapsulated
in epoxy or dipped in varnish.

Did I have to ignore this? was I forced to ignore it?
By whom?

Nice job of backpedalling, Patrick.

Cossover coils can be wound WITHOUT ANY BOBBIN AT ALL.

No they can't. Coils in finished products that lack bobbins were wound on
temporary bobbins. I guess you've never been in a coil factory, Patrick.

Its probably difficult for the DIYer to achieve because
how do you hold the wire
in place as you wind it and after you have wound it?

You use a temporary bobbin, Patrick. I can tell that you never studied
machine tool design or industrial engineering and have never been in an
electrical or electronics factory.

Isn't the 'official' name for such a temporary bobbin a mandrel ?

Graham

[Arny Krueger]

"Eeyore" wrote in
message
Arny Krueger wrote:

"Patrick Turner" wrote in
message
Eeyore wrote:
Arny Krueger wrote:
"Eeyore"
wrote
west wrote:

Did you know this about plastic bobbins?
While reading a Jantzen ad I notice that they
claimed to "not make coils wound on plastic bobbins

So what do they use ?

due to the risk of microphony." I can only think
that perhaps coils in speaker crossovers might be
susceptible.

Why ?

Sounds fairly nutty to me for sure.

Agreed. Note that Pat Turner has to ignore the fact
that coils wound on plastic bobbins can be
encapsulated in epoxy or dipped in varnish.

Did I have to ignore this? was I forced to ignore it?
By whom?

Nice job of backpedalling, Patrick.

Cossover coils can be wound WITHOUT ANY BOBBIN AT ALL.

No they can't. Coils in finished products that lack
bobbins were wound on temporary bobbins. I guess you've
never been in a coil factory, Patrick.

Its probably difficult for the DIYer to achieve because
how do you hold the wire
in place as you wind it and after you have wound it?

You use a temporary bobbin, Patrick. I can tell that you
never studied machine tool design or industrial
engineering and have never been in an electrical or
electronics factory.

Isn't the 'official' name for such a temporary bobbin a
mandrel ?

That is one common kind of temporary bobbin. It's a many-to-many
relationship.