[Serge Auckland]

Trevor Wilson wrote:
"Serge Auckland" wrote in message
...
WindsorFox wrote:
I have some extremely rare tweeters that I need to protect. Can anyone
recommend the size fuse I should use to stop at say 100 watts and at 200
watts?

TIA
I wouldn't use a fuse at all. As others have commented, fuses are too slow
and if of low enough value to protect a tweeter, the series resistance
would affect the response of the crossover.

**And a PolyswitchT makes far more sense, in so many ways.

I would use a VDR (Voltage Dependent Resistor) *across* the tweeter. This
device goes effectively from an open circuit to a short circuit very
quickly (a few nS) when overvoltaged. You need to know what the maximum
short-term voltage the tweeters can take, and size the VDR accordingly.
Note that on overload the VDR will present a short-circuit to the
crossover, and hence in part, to the amplifier. However, the short-circuit
is only present during the over-voltage so on music, if you crank up the
level too high, the VDR will operate only on peaks, and shouldn't affect
the Power Amp, unless it is of a very weak design. The momentary loss of
top, and generally nasty sound will warn you that you're overcooking
things.

**And for all those reasons, a PolyswitchT makes more sense.

Back in the '80s, Mordaunt-Short fitted VDRs as tweeter protection,

**Nope. They used PolyswitchesT. The first speaker company to use them,
AFAIK. Naturally, they were used in series with the tweeters. I confirmed
this in a 'phone call with the designer, back in 1985ish, as I had never
seen such a device before that time. I duly contacted the Australian
distributor (Raychem) and obtained several samples. I've been using them
ever since.



You could be right about Mordaunt-Short. It was a long time ago, so I
could be mistaken. Nevertheless, if you have a series element to the
tweeter, it should be taken into account in the crossover design, and
not added later, which is another reason for using a VDR which goes
across the tweeter.

S.

--
http://audiopages.googlepages.com

[GregS]

In article , Serge Auckland wrote:
Trevor Wilson wrote:
"Serge Auckland" wrote in message
...
WindsorFox wrote:
I have some extremely rare tweeters that I need to protect. Can anyone
recommend the size fuse I should use to stop at say 100 watts and at 200
watts?

TIA
I wouldn't use a fuse at all. As others have commented, fuses are too slow
and if of low enough value to protect a tweeter, the series resistance
would affect the response of the crossover.

**And a PolyswitchT makes far more sense, in so many ways.

I would use a VDR (Voltage Dependent Resistor) *across* the tweeter. This
device goes effectively from an open circuit to a short circuit very
quickly (a few nS) when overvoltaged. You need to know what the maximum
short-term voltage the tweeters can take, and size the VDR accordingly.
Note that on overload the VDR will present a short-circuit to the
crossover, and hence in part, to the amplifier. However, the short-circuit
is only present during the over-voltage so on music, if you crank up the
level too high, the VDR will operate only on peaks, and shouldn't affect
the Power Amp, unless it is of a very weak design. The momentary loss of
top, and generally nasty sound will warn you that you're overcooking
things.

**And for all those reasons, a PolyswitchT makes more sense.

Back in the '80s, Mordaunt-Short fitted VDRs as tweeter protection,

**Nope. They used PolyswitchesT. The first speaker company to use them,
AFAIK. Naturally, they were used in series with the tweeters. I confirmed
this in a 'phone call with the designer, back in 1985ish, as I had never
seen such a device before that time. I duly contacted the Australian
distributor (Raychem) and obtained several samples. I've been using them
ever since.


You could be right about Mordaunt-Short. It was a long time ago, so I
could be mistaken. Nevertheless, if you have a series element to the
tweeter, it should be taken into account in the crossover design, and
not added later, which is another reason for using a VDR which goes
across the tweeter.

With an 8 ohm tweeter, you need at least 1 ohm cold polyswitch or PTC resistor.
I would use a .5 ohm for a 4 ohm tweeter. These values can be tweeked, but
I don't know how many values are available. Many tweeters can be fried with more than a 5 watt
sinewave. For about a 5 watt continiuos rating, the poly switch will be dissapating
1/2 watt, plenty to warm it up and increase the resistance.

greg

[Trevor Wilson]

"GregS" wrote in message
...
In article , "Trevor Wilson"
wrote:

"Serge Auckland" wrote in message
.. .
WindsorFox wrote:
I have some extremely rare tweeters that I need to protect. Can
anyone
recommend the size fuse I should use to stop at say 100 watts and at
200
watts?

TIA

I wouldn't use a fuse at all. As others have commented, fuses are too
slow
and if of low enough value to protect a tweeter, the series resistance
would affect the response of the crossover.

**And a PolyswitchT makes far more sense, in so many ways.

They take too long to work lie a fuse, but can work with avarage current.
It also depends on how much air is circulating around it. A lamp works
well.
A voltage dependent resistor, Much like a MOV, reacts very fast, but has
some additional parallel capacitance. I was using a polyswitch sold by MCM
a few years ago,
and Pyle. i experimented with that device and found it worked with 4 ohm
tweeters, but not 8.

**PolyswitchesT are an excellent replacement for fuses. Sized correctly,
they provide almost foolproof protection for sensitive drivers. I will
repeat that, with emphasis: SIZED CORRECTLY, they provide almost foolproof
protection for sensitive drivers. Incorrectly sized PolyswitchesT operate
the same as incorrectly sized fuses. IOW: Very badly. A lamp is a dumb
speaker protection device, as it has a changing resistance, with
temperature. PolyswitchesT, for all intents, do not. The nice thing about
PolyswitchesT (and fuses) is that they allow short term overload, whilst
operating reasonably quickly under medium term overload. Perfect for
speakers.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[Trevor Wilson]

"Serge Auckland" wrote in message
...
Trevor Wilson wrote:
"Serge Auckland" wrote in message
...
WindsorFox wrote:
I have some extremely rare tweeters that I need to protect. Can
anyone recommend the size fuse I should use to stop at say 100 watts
and at 200 watts?

TIA
I wouldn't use a fuse at all. As others have commented, fuses are too
slow and if of low enough value to protect a tweeter, the series
resistance would affect the response of the crossover.

**And a PolyswitchT makes far more sense, in so many ways.

I would use a VDR (Voltage Dependent Resistor) *across* the tweeter.
This device goes effectively from an open circuit to a short circuit
very quickly (a few nS) when overvoltaged. You need to know what the
maximum short-term voltage the tweeters can take, and size the VDR
accordingly. Note that on overload the VDR will present a short-circuit
to the crossover, and hence in part, to the amplifier. However, the
short-circuit is only present during the over-voltage so on music, if
you crank up the level too high, the VDR will operate only on peaks, and
shouldn't affect the Power Amp, unless it is of a very weak design. The
momentary loss of top, and generally nasty sound will warn you that
you're overcooking things.

**And for all those reasons, a PolyswitchT makes more sense.

Back in the '80s, Mordaunt-Short fitted VDRs as tweeter protection,

**Nope. They used PolyswitchesT. The first speaker company to use them,
AFAIK. Naturally, they were used in series with the tweeters. I confirmed
this in a 'phone call with the designer, back in 1985ish, as I had never
seen such a device before that time. I duly contacted the Australian
distributor (Raychem) and obtained several samples. I've been using them
ever since.



You could be right about Mordaunt-Short.

**No. I AM right about MS speakers. I pulled them apart in the 1980s, when I
tried to destroy a pair of MS10s (their smallest speaker) with a 180 Watt/ch
amp played at clipping. The damned things held together and after a short
time, the vloume reduced dramatically. Intrigued, I stripped them down and
located a component I was unable to identify. That is when I 'phoned MS in
the UK and spoke to the designer. He was most helpful and very forthcoming
with the information I needed.

It was a long time ago, so I
could be mistaken.

**You are.

Nevertheless, if you have a series element to the
tweeter, it should be taken into account in the crossover design, and not
added later, which is another reason for using a VDR which goes across the
tweeter.

**PolyswitchesT exhibit a very low cold resistance, which SHOULD ALWAYS be
taken into account with a crossover design.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[Trevor Wilson]

"GregS" wrote in message
...
In article , Serge Auckland
wrote:
Trevor Wilson wrote:
"Serge Auckland" wrote in message
...
WindsorFox wrote:
I have some extremely rare tweeters that I need to protect. Can
anyone
recommend the size fuse I should use to stop at say 100 watts and at
200
watts?

TIA
I wouldn't use a fuse at all. As others have commented, fuses are too
slow
and if of low enough value to protect a tweeter, the series resistance
would affect the response of the crossover.

**And a PolyswitchT makes far more sense, in so many ways.

I would use a VDR (Voltage Dependent Resistor) *across* the tweeter.
This
device goes effectively from an open circuit to a short circuit very
quickly (a few nS) when overvoltaged. You need to know what the maximum
short-term voltage the tweeters can take, and size the VDR accordingly.
Note that on overload the VDR will present a short-circuit to the
crossover, and hence in part, to the amplifier. However, the
short-circuit
is only present during the over-voltage so on music, if you crank up
the
level too high, the VDR will operate only on peaks, and shouldn't
affect
the Power Amp, unless it is of a very weak design. The momentary loss
of
top, and generally nasty sound will warn you that you're overcooking
things.

**And for all those reasons, a PolyswitchT makes more sense.

Back in the '80s, Mordaunt-Short fitted VDRs as tweeter protection,

**Nope. They used PolyswitchesT. The first speaker company to use them,
AFAIK. Naturally, they were used in series with the tweeters. I
confirmed
this in a 'phone call with the designer, back in 1985ish, as I had never
seen such a device before that time. I duly contacted the Australian
distributor (Raychem) and obtained several samples. I've been using them
ever since.


You could be right about Mordaunt-Short. It was a long time ago, so I
could be mistaken. Nevertheless, if you have a series element to the
tweeter, it should be taken into account in the crossover design, and
not added later, which is another reason for using a VDR which goes
across the tweeter.

With an 8 ohm tweeter, you need at least 1 ohm cold polyswitch or PTC
resistor.

**That is not the important rating of a PolyswitchT. The CURRENT rating is
what matters most.

I would use a .5 ohm for a 4 ohm tweeter. These values can be tweeked, but
I don't know how many values are available.

**Quite a few, as it happens. My supplier lists:

RXE010
RXE017
RXE020
RXE025
RXE030
RXE040
RXE050
RXE065
RXE075
RXE090
RXE110
RXE135
RXE160
RXE185
RXE250
RXE300
RXE375

The last three digits indicate the hold current. IE: RXE050 has a hold
current of 0.5 Amps. Trip current is double the hold current. Therefore, an
RXE050 is appropriate for most tweeters. I would advise never exceeding
RXE110 for any domestic tweeter.


--
Trevor Wilson
www.rageaudio.com.au



Many tweeters can be fried with more than a 5 watt
sinewave. For about a 5 watt continiuos rating, the poly switch will be
dissapating
1/2 watt, plenty to warm it up and increase the resistance.

greg



--
Posted via a free Usenet account from http://www.teranews.com

[Eeyore]

Trevor Wilson wrote:

**PolyswitchesT are an excellent replacement for fuses. Sized correctly,
they provide almost foolproof protection for sensitive drivers. I will
repeat that, with emphasis: SIZED CORRECTLY, they provide almost foolproof
protection for sensitive drivers. Incorrectly sized PolyswitchesT operate
the same as incorrectly sized fuses. IOW: Very badly. A lamp is a dumb
speaker protection device, as it has a changing resistance, with
temperature. PolyswitchesT, for all intents, do not. The nice thing about
PolyswitchesT (and fuses) is that they allow short term overload, whilst
operating reasonably quickly under medium term overload. Perfect for
speakers.

You need a low mass Polyswitch for fast response which is fine here since the
power level is low.

Raychem used to have an excellent application note on their use for audio too.

The only snag is that retrofittting them will incure a slight HF loss. This is
why I suggested a relay based protector.

Graham

[Trevor Wilson]

"Eeyore" wrote in message
...


Trevor Wilson wrote:

**PolyswitchesT are an excellent replacement for fuses. Sized correctly,
they provide almost foolproof protection for sensitive drivers. I will
repeat that, with emphasis: SIZED CORRECTLY, they provide almost
foolproof
protection for sensitive drivers. Incorrectly sized PolyswitchesT operate
the same as incorrectly sized fuses. IOW: Very badly. A lamp is a dumb
speaker protection device, as it has a changing resistance, with
temperature. PolyswitchesT, for all intents, do not. The nice thing about
PolyswitchesT (and fuses) is that they allow short term overload, whilst
operating reasonably quickly under medium term overload. Perfect for
speakers.

You need a low mass Polyswitch for fast response which is fine here since
the
power level is low.

Raychem used to have an excellent application note on their use for audio
too.

The only snag is that retrofittting them will incure a slight HF loss.
This is
why I suggested a relay based protector.

**Certainly, relay systems are much better, but much more complex too.
PolyswitchesT are perfect for morons like the original poster.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[Trevor Wilson]

"Karl Uppiano" wrote in message
news:SCPWh.6234$Fs6.1018@trnddc03...
Yes, and it is for both of those reasons that I suggest fuse values on
the side of caution.

Incrementally increase the fuse rating until just before the tweeter burns
out, and then drop back 1/4 amp :-)

**YIKES! Try that with a pair of Dynaudio Esotars (now virtually
unobtainable, and VERY expensive if you can get them) or a pair Ravens.

I saw the smiley.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[Karl Uppiano]

"Trevor Wilson" wrote in message
.. .

"Karl Uppiano" wrote in message
news:SCPWh.6234$Fs6.1018@trnddc03...
Yes, and it is for both of those reasons that I suggest fuse values on
the side of caution.

Incrementally increase the fuse rating until just before the tweeter
burns out, and then drop back 1/4 amp :-)

**YIKES! Try that with a pair of Dynaudio Esotars (now virtually
unobtainable, and VERY expensive if you can get them) or a pair Ravens.

I saw the smiley.

I actually got that from an honest-to-goodness spec sheet for torquing bolts
on a piece of equipment I had to maintain. It said: "Tighten each fastener
until just before it breaks, and back off 1/4 turn". No kidding.

[Trevor Wilson]

"Karl Uppiano" wrote in message
news:HdDXh.6212$_u2.2159@trnddc04...

"Trevor Wilson" wrote in message
.. .

"Karl Uppiano" wrote in message
news:SCPWh.6234$Fs6.1018@trnddc03...
Yes, and it is for both of those reasons that I suggest fuse values on
the side of caution.

Incrementally increase the fuse rating until just before the tweeter
burns out, and then drop back 1/4 amp :-)

**YIKES! Try that with a pair of Dynaudio Esotars (now virtually
unobtainable, and VERY expensive if you can get them) or a pair Ravens.

I saw the smiley.

I actually got that from an honest-to-goodness spec sheet for torquing
bolts on a piece of equipment I had to maintain. It said: "Tighten each
fastener until just before it breaks, and back off 1/4 turn". No kidding.

**Yikes!

--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[WindsorFox]

Trevor Wilson wrote:
"Eeyore" wrote in message
...

Trevor Wilson wrote:

**PolyswitchesT are an excellent replacement for fuses. Sized correctly,
they provide almost foolproof protection for sensitive drivers. I will
repeat that, with emphasis: SIZED CORRECTLY, they provide almost
foolproof
protection for sensitive drivers. Incorrectly sized PolyswitchesT operate
the same as incorrectly sized fuses. IOW: Very badly. A lamp is a dumb
speaker protection device, as it has a changing resistance, with
temperature. PolyswitchesT, for all intents, do not. The nice thing about
PolyswitchesT (and fuses) is that they allow short term overload, whilst
operating reasonably quickly under medium term overload. Perfect for
speakers.
You need a low mass Polyswitch for fast response which is fine here since
the
power level is low.

Raychem used to have an excellent application note on their use for audio
too.

The only snag is that retrofittting them will incure a slight HF loss.
This is
why I suggested a relay based protector.

**Certainly, relay systems are much better, but much more complex too.
PolyswitchesT are perfect for morons like the original poster.




Does the term FOAD mean anything to you?

--
"Yes, it is a good thing you are handy, as
you clearly suck at being smart." - Herb

[Eeyore]

WindsorFox wrote:

Trevor Wilson wrote:

PolyswitchesT are perfect for morons like the original poster.


Does the term FOAD mean anything to you?

Oh BABY ! Did Trevor upset you ?

Graham

[WindsorFox]

Eeyore wrote:

WindsorFox wrote:

Trevor Wilson wrote:

PolyswitchesT are perfect for morons like the original poster.

Does the term FOAD mean anything to you?

Oh BABY ! Did Trevor upset you ?

Graham



No, did he upset you? Usenet is full of dickhead Aussies that think
they are smarter than the rest of the world, he's just one of a bunch.
As are you. The truth is that no one in this group is in any position to
determine much of anything about anyone else here. I *could* have
referred to you as a moron for your inability to search the Internet,
something I remain above.

--
"Yes, it is a good thing you are handy, as
you clearly suck at being smart." - Herb

[Trevor Wilson]

"WindsorFox" wrote in message
...
Eeyore wrote:

WindsorFox wrote:

Trevor Wilson wrote:

PolyswitchesT are perfect for morons like the original poster.

Does the term FOAD mean anything to you?

Oh BABY ! Did Trevor upset you ?

Graham



No, did he upset you? Usenet is full of dickhead Aussies that think
they are smarter than the rest of the world, he's just one of a bunch.

**I don't think I am smarter than the rest of the world. I KNOW I am smarter
than you (in the area of speakers and speaker protection systems). It's what
I do. I am a professional. You chose not to listen to me. That's your
problem.

As are you. The truth is that no one in this group is in any position to
determine much of anything about anyone else here. I *could* have referred
to you as a moron for your inability to search the Internet, something I
remain above.

**Your comments brand you as a moron. Myself and others gave you all the
information you needed.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[WindsorFox]

Trevor Wilson wrote:
"WindsorFox" wrote in message
...
Eeyore wrote:
WindsorFox wrote:

Trevor Wilson wrote:

PolyswitchesT are perfect for morons like the original poster.
Does the term FOAD mean anything to you?
Oh BABY ! Did Trevor upset you ?

Graham


No, did he upset you? Usenet is full of dickhead Aussies that think
they are smarter than the rest of the world, he's just one of a bunch.

**I don't think I am smarter than the rest of the world. I KNOW I am smarter
than you (in the area of speakers and speaker protection systems). It's what
I do. I am a professional. You chose not to listen to me. That's your
problem.


I chose not to listen to you? Actually you're posts were one of a
few I took seriously.

As are you. The truth is that no one in this group is in any position to
determine much of anything about anyone else here. I *could* have referred
to you as a moron for your inability to search the Internet, something I
remain above.

**Your comments brand you as a moron. Myself and others gave you all the
information you needed.


Then you have a poor definition of "moron," however your comments
are branding you as well and I'd suggest you go out and buy yourself a
sense of humor. I've never commented one way or another whether I do or
do not have the information I need for tweeter protectors. The guy in
the car audio group was right this is more of a google type question but
I decided to see what kind of info I got from the pros here. The
resulting thread has lent proof to a comment I read sometime back
stating that Usenet has become worthless for anything other than
entertainment.


--
"Yes, it is a good thing you are handy, as
you clearly suck at being smart." - Herb

[Eeyore]

WindsorFox wrote:

Eeyore wrote:
WindsorFox wrote:
Trevor Wilson wrote:

PolyswitchesT are perfect for morons like the original poster.

Does the term FOAD mean anything to you?

Oh BABY ! Did Trevor upset you ?


No, did he upset you? Usenet is full of dickhead Aussies that think
they are smarter than the rest of the world, he's just one of a bunch.
As are you.

I'm not Australian.


The truth is that no one in this group is in any position to
determine much of anything about anyone else here.

You certainly can't for sure !


I *could* have referred to you as a moron for your inability to search the
Internet,
something I remain above.

As I believe I said before you need to lose the attitude. You're not going to
get any help by foul-mouthing everyone who knows more than you and that's almost
everyone.


Graham

[WindsorFox]

Eeyore wrote:

As I believe I said before you need to lose the attitude. You're not going to
get any help by foul-mouthing everyone who knows more than you and that's almost
everyone.



*My* attitude??? 1) I've gotten all the help I needed. 2) The only
foul mothung going on here is you, Philbert and aussie-boy. 3) none of
the 3 of you are I assert once more in any position to have a clue what
anyone else in Usenet does or doesn't know. 4) All of this tripe coming
from someone who knows less about computers and sound cards than I have
forgotten is pretty much meaningless.

I received three emails from people who wanted to offer information
but not get involved in or be a target for YOU and Allison's personal
attacks.

--
"Yes, it is a good thing you are handy, as
you clearly suck at being smart." - Herb

[r.berger]

"Peter Larsen" schreef in bericht
...
WindsorFox wrote:

I have some extremely rare tweeters that I need to protect.

Oh, and we are supposed to know which?

Can anyone recommend the size fuse I should use to stop
at say 100 watts and at 200 watts?

Nonsense, tweeter power handling is more like a single digit number of
watts and fast-blo fuse size consequently in the range from some 200
milliamperes and up some 1 ampere, unless of course you want to imply
some 2" entry compression driver when saying tweeter.

Be aware that loudspeaker units can be surprisingly good at protecting
fuses by blowing up first simply because powerhandling is also a matter
of frequency content of the signal, and because X-max concerns also
apply for tweeters.

Another ploy that may be helpful is the automotive bulb ploy, but exact
tweeter specs and more know-how than I have is required to suggest a
suitable bulb for the tweeter-model you ask about.

Just why did you decide to waste your own as well as everybody else's
time by asking a question omitting even the most basic facts?


Kind regards

Peter Larsen

Nobody asked you to waste your time on this!

Regards

Ronald