Jansen electrostatic tweeter questions?

None

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I've got an old pair of Jansen speakers with the electrostatic
tweeters. They're four array radiator types.( four inch square or so
with four to a box.)
I'm thinking about putting them in another speaker box project I'm
working on and could use some advice from any who've had any
experience with these type of tweeters.
One of the individual radiators is badly damaged and I was thinking of
paring them down from four to just three as it might be impossible to
get replacement parts for anything this old. This shouldn't be a
problem should it?
Also they've got a heavy buildup of grime on them from extended
storage. What's the best way to clean them off? (I was thinking a bit
of simple green followed by rinsing with water, then blowing off with
compressed air. Or would it be safe to use a contact cleaner?
Thanks in advance for any info regarding these units.
 
G

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none wrote:


> I've got an old pair of Jansen speakers with the electrostatic
> tweeters. They're four array radiator types.( four inch square or so
> with four to a box.)
> I'm thinking about putting them in another speaker box project I'm
> working on and could use some advice from any who've had any
> experience with these type of tweeters.
> One of the individual radiators is badly damaged and I was thinking of
> paring them down from four to just three as it might be impossible to
> get replacement parts for anything this old. This shouldn't be a
> problem should it?
> Also they've got a heavy buildup of grime on them from extended
> storage. What's the best way to clean them off? (I was thinking a bit
> of simple green followed by rinsing with water, then blowing off with
> compressed air. Or would it be safe to use a contact cleaner?
> Thanks in advance for any info regarding these units.

=======================================

Please note, it's "Janszen" with a "Z", after their inventor, US Navy
engineer Capt. Arthur Janszen. Some of the advertising even had the
name as "JansZen" with a big "Z" so people be less likely to confuse the
product with "Jensen."

Do not use anything liquid on the screens. The polarizing voltage is
1100 volts and if there is any moisture left in them, you will risk
arcing or damage when they are turned on. Brush them lightly with a
soft brush to remove the dust, or blow them lightly with air.

Dropping from four to three screens will drop efficiency, maximum output
and power handling by 25%.

Many of these, after long storage, will suffer from breakdown of the
connection from the center terminal (on the inside of the screen) to the
metalized mylar diaphragm. Symptom of this is low or no output. Don't
be surprised if it doesn't work.

The efficiency of those tweeters is relatively low. At highest output
(which was adjusted by altering the polarizing voltage down from the
maximum 1100 volts), they were barely a match for the AR-1w (the woofer
section of the AR-3). I paired a set with a pair of old AR-2 (tweeters
disconnected) once, just as an experiment, and the woofer predominated.
Just about any modern woofer is more efficient, due to more powerful
magnets and improved materials, and the use of ducted ports on most.

Sometimes an old set may have bad rectifiers in the polarizing supply.
Early ones had selenium rectifiers that have probably long gone bad.
Just be aware if repairing it, that it's an 1100 volt supply. A common
1N4004 diode won't do the job, even though the current draw is minimal.
And be very careful poking around inside, for your own safety.

That said...if you have a good-working set of Janszen electrostatic
tweeters, and they are well matched with your woofers, their performance
is glorious, if somewhat beamy due to the four flat radiators. That was
my preferred speaker system for years, and although they aren't hooked
up now, I still have my two Janszen 130 tweeters, the pair of AR-3, and
a pair of cast-frame AR 12-inch woofers which I bought secondhand, for
"just in case" replacement parts.

-GP
 
G

Guest

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Archived from groups: rec.audio.high-end (More info?)

Gene Poon wrote about the JansZen electrostatic tweeters:


> Many of these, after long storage, will suffer from breakdown of the
> connection from the center terminal (on the inside of the screen) to the
> metalized mylar diaphragm. Symptom of this is low or no output. Don't
> be surprised if it doesn't work.

I should have mentioned that in many cases there is a low-cost fix.
When the JansZens were popular, I fixed quite a few by installing an
external contact to the diaphragm.

-GP
 

None

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On 17 Apr 2005 15:13:40 GMT, Gene Poon <sheehans@ap.net> wrote:

>none wrote:
>
>
>> I've got an old pair of Jansen speakers with the electrostatic
>> tweeters. They're four array radiator types.( four inch square or so
>> with four to a box.)
>> I'm thinking about putting them in another speaker box project I'm
>> working on and could use some advice from any who've had any
>> experience with these type of tweeters.
>> One of the individual radiators is badly damaged and I was thinking of
>> paring them down from four to just three as it might be impossible to
>> get replacement parts for anything this old. This shouldn't be a
>> problem should it?
>> Also they've got a heavy buildup of grime on them from extended
>> storage. What's the best way to clean them off? (I was thinking a bit
>> of simple green followed by rinsing with water, then blowing off with
>> compressed air. Or would it be safe to use a contact cleaner?
>> Thanks in advance for any info regarding these units.
>
>=======================================
>
>Please note, it's "Janszen" with a "Z", after their inventor, US Navy
>engineer Capt. Arthur Janszen. Some of the advertising even had the
>name as "JansZen" with a big "Z" so people be less likely to confuse the
>product with "Jensen."
>
>Do not use anything liquid on the screens. The polarizing voltage is
>1100 volts and if there is any moisture left in them, you will risk
>arcing or damage when they are turned on. Brush them lightly with a
>soft brush to remove the dust, or blow them lightly with air.
>
>Dropping from four to three screens will drop efficiency, maximum output
>and power handling by 25%.
>
>Many of these, after long storage, will suffer from breakdown of the
>connection from the center terminal (on the inside of the screen) to the
>metalized mylar diaphragm. Symptom of this is low or no output. Don't
>be surprised if it doesn't work.
>
>The efficiency of those tweeters is relatively low. At highest output
>(which was adjusted by altering the polarizing voltage down from the
>maximum 1100 volts), they were barely a match for the AR-1w (the woofer
>section of the AR-3). I paired a set with a pair of old AR-2 (tweeters
>disconnected) once, just as an experiment, and the woofer predominated.
> Just about any modern woofer is more efficient, due to more powerful
>magnets and improved materials, and the use of ducted ports on most.
>
>Sometimes an old set may have bad rectifiers in the polarizing supply.
>Early ones had selenium rectifiers that have probably long gone bad.
>Just be aware if repairing it, that it's an 1100 volt supply. A common
>1N4004 diode won't do the job, even though the current draw is minimal.
> And be very careful poking around inside, for your own safety.
>
>That said...if you have a good-working set of Janszen electrostatic
>tweeters, and they are well matched with your woofers, their performance
>is glorious, if somewhat beamy due to the four flat radiators. That was
>my preferred speaker system for years, and although they aren't hooked
>up now, I still have my two Janszen 130 tweeters, the pair of AR-3, and
>a pair of cast-frame AR 12-inch woofers which I bought secondhand, for
>"just in case" replacement parts.
>
>-GP

Thanks for all the info.
I had these things collecting dust in the back of my warehouse for
years and thought it'd be nice to put them in a pair of studio
monitors I'm building.
Someone had tried to pry out one of the units and cracked it along the
edge, it did straighten out though and physically looks fine.
They're 5 inch square with the patent # 2,896,025 on the edge if that
helps ID them for you.
They're really grimey from the long storage and will have to be taken
apart for cleaning if you could give me details on how to do that.
(I've done alot of electronic repair in my time so it's not beyond my
ability, just need the details on these particular electrostats.)
If you have links to any sites on these tweeters it'd be a big help.

I think they may be the 130's(I've stripped all electronics/drivers
out of the boxes). There was nothing on the boxes themselves to
indicate model.
The power supply/comtrol unit is all solid state with 12 caps, 2 5000
ohm resistors various other small resistors/diodes as well as a
transformer coil and the choke coil and cap for the woofer.
The control pot is a 20meg wire wound.
Hope this helps.

I do still have the woofers that came in the boxes and they are in
near mint condition.
12 inch with a rubberized 5 pleat edge and heavy cone.
They test out really good for being as old as they are.
I'd put them up against most made today, will probably put them in
some smaller boxes in some future project.
Thanks again for all the info.
 
G

Guest

Guest
Archived from groups: rec.audio.high-end (More info?)

none wrote:

> Someone had tried to pry out one of the units and cracked it along the
> edge, it did straighten out though and physically looks fine.
> They're 5 inch square with the patent # 2,896,025 on the edge if that
> helps ID them for you.
> They're really grimey from the long storage and will have to be taken
> apart for cleaning if you could give me details on how to do that.
> (I've done alot of electronic repair in my time so it's not beyond my
> ability, just need the details on these particular electrostats.)
> If you have links to any sites on these tweeters it'd be a big help.
=====================

I don't know of any sites about repairing them, but that's mostly
because I haven't really looked. I just sort of jumped in, years ago.

The JansZen screens can NOT be disassembled for cleaning. They're glued
together permanently. All you can really do is to lightly brush or
vacuum them to get as much dust out from between the stators and the
diaphragm, as you can.

-GP
 
G

Guest

Guest
Archived from groups: rec.audio.high-end (More info?)

Incidentally, there are two different versions of the JansZen
electrostatic tweeter screens. Both are constructed like a sandwich;
the diaphragm and fiber spacers are analogous to the meat in a sandwich,
and the plastic frames and stators to the bread.

On the earlier version, built until about the late 1960s or early 1970s,
the plastic frames had the stator wires on the inside only. To the
outside, what you saw was the square holes moulded into the plastic,
with the stator wire grid behind the holes. In the later version, the
stator wires were spiral-wound around the plastic frame. What you saw
outside was the actual insulated stator wire; the square holes were
still there, underneath them. Old JansZen speakers sent in for repair
after the new design was introduced, would come back with the new
screens. The factory considered them to be directly interchangeable.

Power handling in the JansZen electrostatics was limited by another
factor than the usual diaphragm-excursion characteristic of dynamic
speakers. If driven too hard, the air between the stators and the
diaphragm would ionize and the polarizing voltage would drain off. This
resulted in the strange characteristic of increased power to the screen
resulting in lower output, but still with low distortion.
 

None

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On 20 Apr 2005 23:59:40 GMT, Gene Poon <sheehans@ap.net> wrote:

>none wrote:
>
>> Someone had tried to pry out one of the units and cracked it along the
>> edge, it did straighten out though and physically looks fine.
>> They're 5 inch square with the patent # 2,896,025 on the edge if that
>> helps ID them for you.
>> They're really grimey from the long storage and will have to be taken
>> apart for cleaning if you could give me details on how to do that.
>> (I've done alot of electronic repair in my time so it's not beyond my
>> ability, just need the details on these particular electrostats.)
>> If you have links to any sites on these tweeters it'd be a big help.
>=====================
>
>I don't know of any sites about repairing them, but that's mostly
>because I haven't really looked. I just sort of jumped in, years ago.
>
>The JansZen screens can NOT be disassembled for cleaning. They're glued
>together permanently. All you can really do is to lightly brush or
>vacuum them to get as much dust out from between the stators and the
>diaphragm, as you can.
>
>-GP

I must have the older ones as there are no external wires.
I do believe I can get them apart though, with a bit of care.
There are three brass rivets at the bottom which I'll drill out and
the three bolt style conact posts holding it together at the top.
I really need to get them apart as it's not dust but a heavy film of
grunge that won't brush off.
I'll use a mild solvent to loosen the glue that holds the plastic
frame together.
I have a pretty complete work bench of micro tools that I use for
servicing micro-electronics in cameras and other electronic devices.
I've talked with some diy'ers at an electrostatic forum who've been a
big help on general ESL theory and construction tho' I'm still looking
around for some sort of exploded diagrahm for these units.(Most have
told me that if all else fails it's fairly easy to build a set of flat
panels that'll run off the Janszen power supplies.)
And from what I've read there are all sorts of improvements in both
the mylars and coatings used in electrostats since these were
designed.
I wouldn't mind having a crack at upgrading these units if the
origianal diaphrams are bad.
Thanks again for the advice.
 

Bear

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Gene Poon wrote:
> Incidentally, there are two different versions of the JansZen
> electrostatic tweeter screens. Both are constructed like a sandwich;
> the diaphragm and fiber spacers are analogous to the meat in a sandwich,
> and the plastic frames and stators to the bread.
>
> On the earlier version, built until about the late 1960s or early 1970s,
> the plastic frames had the stator wires on the inside only. To the
> outside, what you saw was the square holes moulded into the plastic,
> with the stator wire grid behind the holes. In the later version, the
> stator wires were spiral-wound around the plastic frame. What you saw
> outside was the actual insulated stator wire; the square holes were
> still there, underneath them. Old JansZen speakers sent in for repair
> after the new design was introduced, would come back with the new
> screens. The factory considered them to be directly interchangeable.
>
> Power handling in the JansZen electrostatics was limited by another
> factor than the usual diaphragm-excursion characteristic of dynamic
> speakers. If driven too hard, the air between the stators and the
> diaphragm would ionize and the polarizing voltage would drain off. This
> resulted in the strange characteristic of increased power to the screen
> resulting in lower output, but still with low distortion.


Never heard of or saw these spiral jobbers - any pix on the web or jpegs
you may have??

Also, you can't wash the JanZens because they have a graphite diaphragm,
you'll wash that off and they won't work.


_-_-bear


http://www.bearlabs.com


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