In article ,
(Svante) wrote:

I see every now and then people talking about putting fuses in series
with the loudspeaker. It is a nice thought, since the drivers in a
system could be individually fused. Tweeters would love that :-) . But
I have also heard that this would induce distorsion since the metal in
the fuse would have to become heated (otherwise it would never melt)
and thus possibly inducing a signal dependent resistance in series
with the speaker.

Is this a problem, or is it a too small effect?

There are some excellent amps that have a protection fuse inside the
feedback loop. That nicely deals with any nonlinearity due to heating,
but still gives protection to the woofer from a catastrophic event such
as an output device failure.

Tweeters have very low-mass wires, and generally do a fine job of
protecting your fuses, because they have a smaller time constant 8^}.

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Isaac

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

An advantage and disadvantage of the zener approach is that they are
fast.

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well. There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

Even though a Polyswitch provides very good protection, I've seen users
abuse their speakers to the point that they blow-up the tweeter and the
Polyswitch. It usually takes a few weeks to do this, but there is a
limit to the Polyswitch's good humor. One shortcomming to the
Polyswitch approach is that, when the limit is reached, the tweeter
output is reduced. Some customers interpret this as a need to turn
things up a bit to compensate for the loss of trebble. Once the
situation reaches that point, it's a downward spiral.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

An advantage and disadvantage of the zener approach is that they are
fast.

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well. There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

Even though a Polyswitch provides very good protection, I've seen users
abuse their speakers to the point that they blow-up the tweeter and the
Polyswitch. It usually takes a few weeks to do this, but there is a
limit to the Polyswitch's good humor. One shortcomming to the
Polyswitch approach is that, when the limit is reached, the tweeter
output is reduced. Some customers interpret this as a need to turn
things up a bit to compensate for the loss of trebble. Once the
situation reaches that point, it's a downward spiral.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

An advantage and disadvantage of the zener approach is that they are
fast.

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well. There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

Even though a Polyswitch provides very good protection, I've seen users
abuse their speakers to the point that they blow-up the tweeter and the
Polyswitch. It usually takes a few weeks to do this, but there is a
limit to the Polyswitch's good humor. One shortcomming to the
Polyswitch approach is that, when the limit is reached, the tweeter
output is reduced. Some customers interpret this as a need to turn
things up a bit to compensate for the loss of trebble. Once the
situation reaches that point, it's a downward spiral.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

An advantage and disadvantage of the zener approach is that they are
fast.

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well. There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

Even though a Polyswitch provides very good protection, I've seen users
abuse their speakers to the point that they blow-up the tweeter and the
Polyswitch. It usually takes a few weeks to do this, but there is a
limit to the Polyswitch's good humor. One shortcomming to the
Polyswitch approach is that, when the limit is reached, the tweeter
output is reduced. Some customers interpret this as a need to turn
things up a bit to compensate for the loss of trebble. Once the
situation reaches that point, it's a downward spiral.

-----------------------------------------------------------
spam:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------

snipped:
"Isaac Wingfield" wrote in message
...

There are some excellent amps that have a protection fuse inside the
feedback loop. That nicely deals with any nonlinearity due to heating,
but still gives protection to the woofer from a catastrophic event such
as an output device failure.

Tweeters have very low-mass wires, and generally do a fine job of
protecting your fuses, because they have a smaller time constant 8^}.
..

Isaac
----------------------

Isaac Wingfield:
The good news about tweeters and mid-range is that the speaker's cross-over
network will usually have a capacitor in series with the driver and thus
protecting it from long term DC ........ while thumps can still get
through, usually tweeters fail from being over-driven... particularly with
distortion artifacts if the amp is driven into distortion or is just too
powerful for the speaker. As you indicated in your posting, the fuse
in-line from the amp to the speaker is primarily there to protect the woofer
from catastrophic amp failure since it's voice coil is "directly" (no
capacitor, maybe an inductor) connected to the amp.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------
..
..
..
..

snipped:
"Isaac Wingfield" wrote in message
...

There are some excellent amps that have a protection fuse inside the
feedback loop. That nicely deals with any nonlinearity due to heating,
but still gives protection to the woofer from a catastrophic event such
as an output device failure.

Tweeters have very low-mass wires, and generally do a fine job of
protecting your fuses, because they have a smaller time constant 8^}.
..

Isaac
----------------------

Isaac Wingfield:
The good news about tweeters and mid-range is that the speaker's cross-over
network will usually have a capacitor in series with the driver and thus
protecting it from long term DC ........ while thumps can still get
through, usually tweeters fail from being over-driven... particularly with
distortion artifacts if the amp is driven into distortion or is just too
powerful for the speaker. As you indicated in your posting, the fuse
in-line from the amp to the speaker is primarily there to protect the woofer
from catastrophic amp failure since it's voice coil is "directly" (no
capacitor, maybe an inductor) connected to the amp.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------
..
..
..
..

snipped:
"Isaac Wingfield" wrote in message
...

There are some excellent amps that have a protection fuse inside the
feedback loop. That nicely deals with any nonlinearity due to heating,
but still gives protection to the woofer from a catastrophic event such
as an output device failure.

Tweeters have very low-mass wires, and generally do a fine job of
protecting your fuses, because they have a smaller time constant 8^}.
..

Isaac
----------------------

Isaac Wingfield:
The good news about tweeters and mid-range is that the speaker's cross-over
network will usually have a capacitor in series with the driver and thus
protecting it from long term DC ........ while thumps can still get
through, usually tweeters fail from being over-driven... particularly with
distortion artifacts if the amp is driven into distortion or is just too
powerful for the speaker. As you indicated in your posting, the fuse
in-line from the amp to the speaker is primarily there to protect the woofer
from catastrophic amp failure since it's voice coil is "directly" (no
capacitor, maybe an inductor) connected to the amp.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------
..
..
..
..

snipped:
"Isaac Wingfield" wrote in message
...

There are some excellent amps that have a protection fuse inside the
feedback loop. That nicely deals with any nonlinearity due to heating,
but still gives protection to the woofer from a catastrophic event such
as an output device failure.

Tweeters have very low-mass wires, and generally do a fine job of
protecting your fuses, because they have a smaller time constant 8^}.
..

Isaac
----------------------

Isaac Wingfield:
The good news about tweeters and mid-range is that the speaker's cross-over
network will usually have a capacitor in series with the driver and thus
protecting it from long term DC ........ while thumps can still get
through, usually tweeters fail from being over-driven... particularly with
distortion artifacts if the amp is driven into distortion or is just too
powerful for the speaker. As you indicated in your posting, the fuse
in-line from the amp to the speaker is primarily there to protect the woofer
from catastrophic amp failure since it's voice coil is "directly" (no
capacitor, maybe an inductor) connected to the amp.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------
..
..
..
..

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?

"Svante" wrote in message
One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?
---------------------------------


Svante:
Usually most brands and most types of Fast Blow fuses are specified by the
manufacturer to take 200% of rating for NO MORE than 5 seconds while the
Slow Blow version can take 200% of rating of AT LEAST 5 seconds and upwards
to 60 seconds or more.
Obviously higher amperage surges can take them out faster.
For purposes of protecting speaker voice coils from being fried by
malfunctioning amplifier circuitry..... the absolute value of the fuse is
not that critical...... usually a fast blow fuse rated between 2 to 5 amps
will do the trick for most home applications.
An old rule of thumb used while I was in the pro-audio installation
business, and not necessarily derived by a specific formula for specific
speakers and amplifier impedances... was 1 amp per 25 watts..... just a
rule of thumb in most applications... of course these values can be juggled
by the purist and the knit-pickers with their slide rules and scientific
calculators. A lot will depend of course on the installation and
listening habits..... peak watts produced, heavy thumping bass, etc. .....
as I said, not that critical....and as long as there is a fuse in there, it
will probably and hopefully melt before the woofer voice coil if the
amplifier fails.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
---------------------
..
..
..
..

"Svante" wrote in message
One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?
---------------------------------


Svante:
Usually most brands and most types of Fast Blow fuses are specified by the
manufacturer to take 200% of rating for NO MORE than 5 seconds while the
Slow Blow version can take 200% of rating of AT LEAST 5 seconds and upwards
to 60 seconds or more.
Obviously higher amperage surges can take them out faster.
For purposes of protecting speaker voice coils from being fried by
malfunctioning amplifier circuitry..... the absolute value of the fuse is
not that critical...... usually a fast blow fuse rated between 2 to 5 amps
will do the trick for most home applications.
An old rule of thumb used while I was in the pro-audio installation
business, and not necessarily derived by a specific formula for specific
speakers and amplifier impedances... was 1 amp per 25 watts..... just a
rule of thumb in most applications... of course these values can be juggled
by the purist and the knit-pickers with their slide rules and scientific
calculators. A lot will depend of course on the installation and
listening habits..... peak watts produced, heavy thumping bass, etc. .....
as I said, not that critical....and as long as there is a fuse in there, it
will probably and hopefully melt before the woofer voice coil if the
amplifier fails.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
---------------------
..
..
..
..

"Svante" wrote in message
One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?
---------------------------------


Svante:
Usually most brands and most types of Fast Blow fuses are specified by the
manufacturer to take 200% of rating for NO MORE than 5 seconds while the
Slow Blow version can take 200% of rating of AT LEAST 5 seconds and upwards
to 60 seconds or more.
Obviously higher amperage surges can take them out faster.
For purposes of protecting speaker voice coils from being fried by
malfunctioning amplifier circuitry..... the absolute value of the fuse is
not that critical...... usually a fast blow fuse rated between 2 to 5 amps
will do the trick for most home applications.
An old rule of thumb used while I was in the pro-audio installation
business, and not necessarily derived by a specific formula for specific
speakers and amplifier impedances... was 1 amp per 25 watts..... just a
rule of thumb in most applications... of course these values can be juggled
by the purist and the knit-pickers with their slide rules and scientific
calculators. A lot will depend of course on the installation and
listening habits..... peak watts produced, heavy thumping bass, etc. .....
as I said, not that critical....and as long as there is a fuse in there, it
will probably and hopefully melt before the woofer voice coil if the
amplifier fails.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
---------------------
..
..
..
..

"Svante" wrote in message
One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

Opinions?
---------------------------------


Svante:
Usually most brands and most types of Fast Blow fuses are specified by the
manufacturer to take 200% of rating for NO MORE than 5 seconds while the
Slow Blow version can take 200% of rating of AT LEAST 5 seconds and upwards
to 60 seconds or more.
Obviously higher amperage surges can take them out faster.
For purposes of protecting speaker voice coils from being fried by
malfunctioning amplifier circuitry..... the absolute value of the fuse is
not that critical...... usually a fast blow fuse rated between 2 to 5 amps
will do the trick for most home applications.
An old rule of thumb used while I was in the pro-audio installation
business, and not necessarily derived by a specific formula for specific
speakers and amplifier impedances... was 1 amp per 25 watts..... just a
rule of thumb in most applications... of course these values can be juggled
by the purist and the knit-pickers with their slide rules and scientific
calculators. A lot will depend of course on the installation and
listening habits..... peak watts produced, heavy thumping bass, etc. .....
as I said, not that critical....and as long as there is a fuse in there, it
will probably and hopefully melt before the woofer voice coil if the
amplifier fails.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
---------------------
..
..
..
..

In article ,
(Barry Mann) wrote:

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

The series capacitor in the crossover prevents DC from flowing, so the
only risk to the tweeter is from high-frequency transients. If 5 or 10
watt zeners are used, there's no problem.

An advantage and disadvantage of the zener approach is that they are
fast.

The advantage is clear. What is the disadvantage?

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well.

Also, it's rather nonlinear at levels far below those where it provides
any actual protection. Worse than a fuse, I suspect.

There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

I suspect the reason those are used in commercial speakers is that they
are less expensive than good zeners. I don't think they are superior, or
even equivalent, in terms of their actual performance.

Isaac

In article ,
(Barry Mann) wrote:

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

The series capacitor in the crossover prevents DC from flowing, so the
only risk to the tweeter is from high-frequency transients. If 5 or 10
watt zeners are used, there's no problem.

An advantage and disadvantage of the zener approach is that they are
fast.

The advantage is clear. What is the disadvantage?

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well.

Also, it's rather nonlinear at levels far below those where it provides
any actual protection. Worse than a fuse, I suspect.

There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

I suspect the reason those are used in commercial speakers is that they
are less expensive than good zeners. I don't think they are superior, or
even equivalent, in terms of their actual performance.

Isaac

In article ,
(Barry Mann) wrote:

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

The series capacitor in the crossover prevents DC from flowing, so the
only risk to the tweeter is from high-frequency transients. If 5 or 10
watt zeners are used, there's no problem.

An advantage and disadvantage of the zener approach is that they are
fast.

The advantage is clear. What is the disadvantage?

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well.

Also, it's rather nonlinear at levels far below those where it provides
any actual protection. Worse than a fuse, I suspect.

There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

I suspect the reason those are used in commercial speakers is that they
are less expensive than good zeners. I don't think they are superior, or
even equivalent, in terms of their actual performance.

Isaac

In article ,
(Barry Mann) wrote:

In , on 02/19/04
at 05:19 AM, Isaac Wingfield said:

[ ... ]

I have seen tweeter protection implemented with a pair of
appropriate-sized zener diodes in opposite polarity and in *series*,
placed across the tweeter. I think that should work, as their action
would be very fast. Near to the zener voltage, there would be some
nonlinearity.

Hopefully, there is some form of current limiting between the zener's
and the power amplifier. Otherwise, when a diode turns on there will be
a brief struggle to see who has the most beef -- the amplifier or the
diode.

The series capacitor in the crossover prevents DC from flowing, so the
only risk to the tweeter is from high-frequency transients. If 5 or 10
watt zeners are used, there's no problem.

An advantage and disadvantage of the zener approach is that they are
fast.

The advantage is clear. What is the disadvantage?

An old approach is to insert an incandescent lamp in series with the
speaker. When cold, the lamp's resistance is very low. As the speaker
current increases, the lamp begins to turn on and the series resistance
increases dramatically, thus limiting the current. It's clever, but the
choice of lamp is somewhat limited and the switch point may not match
the speaker's needs very well.

Also, it's rather nonlinear at levels far below those where it provides
any actual protection. Worse than a fuse, I suspect.

There are more modern devices, one trade
name is "Polyswitch," that are commonly used to protect tweeters. They
are available in a variety of sizes and their switching characteristics
are well suited for protecting tweeters.

I suspect the reason those are used in commercial speakers is that they
are less expensive than good zeners. I don't think they are superior, or
even equivalent, in terms of their actual performance.

Isaac

In article ,
(Svante) wrote:

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The time constant of the nonlinearity of a fuse is too long to show up
during a cycle of any audible frequency. It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning down
the volume" a bit at hight levels. Whether or not it is noticeable is
another issue.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

If a fuse is expected to hold *forever* at its rated current, it's not
going to blow any too fast at only a 100% overload. To get anything like
"fast" action, you'll need to provide about 10X rated current.

There's a special variety of low-current fuse called an "instrument
fuse" with a very low time constant that's intended to protect
D'Arsonval meters. They are not cheap.

Isaac

In article ,
(Svante) wrote:

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The time constant of the nonlinearity of a fuse is too long to show up
during a cycle of any audible frequency. It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning down
the volume" a bit at hight levels. Whether or not it is noticeable is
another issue.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

If a fuse is expected to hold *forever* at its rated current, it's not
going to blow any too fast at only a 100% overload. To get anything like
"fast" action, you'll need to provide about 10X rated current.

There's a special variety of low-current fuse called an "instrument
fuse" with a very low time constant that's intended to protect
D'Arsonval meters. They are not cheap.

Isaac

In article ,
(Svante) wrote:

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The time constant of the nonlinearity of a fuse is too long to show up
during a cycle of any audible frequency. It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning down
the volume" a bit at hight levels. Whether or not it is noticeable is
another issue.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

If a fuse is expected to hold *forever* at its rated current, it's not
going to blow any too fast at only a 100% overload. To get anything like
"fast" action, you'll need to provide about 10X rated current.

There's a special variety of low-current fuse called an "instrument
fuse" with a very low time constant that's intended to protect
D'Arsonval meters. They are not cheap.

Isaac

In article ,
(Svante) wrote:

(Svante) wrote in message
Mmm... Some claim to hear cables, so I am not surprised. But the fuse
effect is possibly larger than the cable effect, since there is a
piece of wire that actually is near melting at full power. The
question is how much larger. I think I'll do an experiment. A power
amplifier, a tone generator, a 8 ohm resistor and a 1 amp fuse.
Measure the voltage over the resistance and see if there is any
distorsion. If so does it increase with power. Hmm...

OK, so I did the experiment. It did not turn out quite as I wanted it
due to the equipment I got hold of, but it gives a rough idea about
the magnitude of these effects.

I hooked up the computer to an amplifier and a 500mA quickblow fuse in
series with 3.3 ohms. I meanured the voltage across the *fuse* (this
should reveal any distortion products even more). At 1kHz it turns out
that the 3rd harmonic is 60 dB down (0.1% distortion). In the feeding
signal it is 80 dB down, so there is a slight increase in the
distortion, but not very much to worry about. Across the resistor, the
distortion should be lower, presumably somewhere around 0.03%.
However, the resistance of the fuse increases with the current through
it, and just before it blows, the resistance was about 0.9 ohms. If I
connect a cold fuse to the multimeter it reads about 0.2-0.3 ohms.
This fits well with the melting point of silver which is some 960
degrees celsius, or four times the room temperature, measured in
kelvin. Since resistance is proportional to absolute temperature, the
resistance *should* increase by a factor four just before meltdown.
I also tried the same thing at 10 Hz, lower frequency should provoke a
higher distortion since the temperature more easily can follow the
fluctuations of the voltage. However, the amplifier I got hold of
appeared to have a problem with delivering the signal at these low
frequencies, the third harmonic is now 50 dB down, with the fuse
shorted. The most I can say is that the distortion is *less than*
-50dB or 0.3%. The resistance increase was the same as for 1kHz.

The time constant of the nonlinearity of a fuse is too long to show up
during a cycle of any audible frequency. It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning down
the volume" a bit at hight levels. Whether or not it is noticeable is
another issue.

The increased resistance would IMO be the only reason to avoid using
ordinary fuses in series with the loudspeaker (regarding the
audibility). The distortion is low compared to other sources,
especially near the maximum output level of the speaker. A series
resistance of 1 ohm may alter the frequency response slightly of the
speaker, and thus make the fuse "audible". The difference will however
be small, and not certainly for the worse.

One more thing I learned. The fuse broke at about 1 ampére, even
though it was rated 500mA. I recall knowing this some time in the
past, but had forgotten about it. Fuses can take more than they
"state".

If a fuse is expected to hold *forever* at its rated current, it's not
going to blow any too fast at only a 100% overload. To get anything like
"fast" action, you'll need to provide about 10X rated current.

There's a special variety of low-current fuse called an "instrument
fuse" with a very low time constant that's intended to protect
D'Arsonval meters. They are not cheap.

Isaac

"Arny Krueger" wrote in message
...
"Tim Schwartz" wrote in message

Yup. It also helps to look at the *final* value you settle on. If it is
too
large, which might be something like a 3 amp fuse in series with a small
tweeter, it's probably predicting the early demise of the driver.

Even the 2A is going to be too much for a tweeter alone, so if you fuse each
driver separately you just use a smaller fuse for the tweeter. 1A will
probably be more than sufficient for the average 8 ohm, 1" dome. Better to
use a polyswitch though.

TonyP.

"Arny Krueger" wrote in message
...
"Tim Schwartz" wrote in message

Yup. It also helps to look at the *final* value you settle on. If it is
too
large, which might be something like a 3 amp fuse in series with a small
tweeter, it's probably predicting the early demise of the driver.

Even the 2A is going to be too much for a tweeter alone, so if you fuse each
driver separately you just use a smaller fuse for the tweeter. 1A will
probably be more than sufficient for the average 8 ohm, 1" dome. Better to
use a polyswitch though.

TonyP.

"Arny Krueger" wrote in message
...
"Tim Schwartz" wrote in message

Yup. It also helps to look at the *final* value you settle on. If it is
too
large, which might be something like a 3 amp fuse in series with a small
tweeter, it's probably predicting the early demise of the driver.

Even the 2A is going to be too much for a tweeter alone, so if you fuse each
driver separately you just use a smaller fuse for the tweeter. 1A will
probably be more than sufficient for the average 8 ohm, 1" dome. Better to
use a polyswitch though.

TonyP.

"Arny Krueger" wrote in message
...
"Tim Schwartz" wrote in message

Yup. It also helps to look at the *final* value you settle on. If it is
too
large, which might be something like a 3 amp fuse in series with a small
tweeter, it's probably predicting the early demise of the driver.

Even the 2A is going to be too much for a tweeter alone, so if you fuse each
driver separately you just use a smaller fuse for the tweeter. 1A will
probably be more than sufficient for the average 8 ohm, 1" dome. Better to
use a polyswitch though.

TonyP.

"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they exhibit
transmission-line characteristics. Lumped representations of cables are
suggested with consideration of the effects cable parameters might have on
the audio signal being transmitted. Interaction of the cable with the
amplifier, the loudspeaker, and other elements which may be part of the
amplifier·cable·loudspeaker circuit are treated.


It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning
down the volume" a bit at high levels.

That, too.

Whether or not it is noticeable is another issue.

The Greiner article found 0.5 to 4% nonlinear distortion using 20 & 5000 Hz
test tones, in fuses in the 2-5 amp range. Power levels were just below
observed burn out of the fuse.

The article also pointed out that multiway speaker systems with fuses for
each driver tended to minimize these effects for pretty obvious reasons.

"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they exhibit
transmission-line characteristics. Lumped representations of cables are
suggested with consideration of the effects cable parameters might have on
the audio signal being transmitted. Interaction of the cable with the
amplifier, the loudspeaker, and other elements which may be part of the
amplifier·cable·loudspeaker circuit are treated.


It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning
down the volume" a bit at high levels.

That, too.

Whether or not it is noticeable is another issue.

The Greiner article found 0.5 to 4% nonlinear distortion using 20 & 5000 Hz
test tones, in fuses in the 2-5 amp range. Power levels were just below
observed burn out of the fuse.

The article also pointed out that multiway speaker systems with fuses for
each driver tended to minimize these effects for pretty obvious reasons.

"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they exhibit
transmission-line characteristics. Lumped representations of cables are
suggested with consideration of the effects cable parameters might have on
the audio signal being transmitted. Interaction of the cable with the
amplifier, the loudspeaker, and other elements which may be part of the
amplifier·cable·loudspeaker circuit are treated.


It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning
down the volume" a bit at high levels.

That, too.

Whether or not it is noticeable is another issue.

The Greiner article found 0.5 to 4% nonlinear distortion using 20 & 5000 Hz
test tones, in fuses in the 2-5 amp range. Power levels were just below
observed burn out of the fuse.

The article also pointed out that multiway speaker systems with fuses for
each driver tended to minimize these effects for pretty obvious reasons.

"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they exhibit
transmission-line characteristics. Lumped representations of cables are
suggested with consideration of the effects cable parameters might have on
the audio signal being transmitted. Interaction of the cable with the
amplifier, the loudspeaker, and other elements which may be part of the
amplifier·cable·loudspeaker circuit are treated.


It'll manifest as a higher
resistance during loud passages -- the effect will be like "turning
down the volume" a bit at high levels.

That, too.

Whether or not it is noticeable is another issue.

The Greiner article found 0.5 to 4% nonlinear distortion using 20 & 5000 Hz
test tones, in fuses in the 2-5 amp range. Power levels were just below
observed burn out of the fuse.

The article also pointed out that multiway speaker systems with fuses for
each driver tended to minimize these effects for pretty obvious reasons.

"Arny Krueger" wrote in message
...
"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to
show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in
the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they
exhibit
transmission-line characteristics. Lumped representations of cables
are
suggested with consideration of the effects cable parameters might
have on
the audio signal being transmitted. Interaction of the cable with
the
amplifier, the loudspeaker, and other elements which may be part of
the
amplifier·cable·loudspeaker circuit are treated.

Has anyone come across a loudspeaker protected by a positive tempco
resistor? These devices go from very low resistance to almost open
circuit over a very narrow temperature range.

Norm Strong

"Arny Krueger" wrote in message
...
"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to
show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in
the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they
exhibit
transmission-line characteristics. Lumped representations of cables
are
suggested with consideration of the effects cable parameters might
have on
the audio signal being transmitted. Interaction of the cable with
the
amplifier, the loudspeaker, and other elements which may be part of
the
amplifier·cable·loudspeaker circuit are treated.

Has anyone come across a loudspeaker protected by a positive tempco
resistor? These devices go from very low resistance to almost open
circuit over a very narrow temperature range.

Norm Strong

"Arny Krueger" wrote in message
...
"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to
show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in
the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they
exhibit
transmission-line characteristics. Lumped representations of cables
are
suggested with consideration of the effects cable parameters might
have on
the audio signal being transmitted. Interaction of the cable with
the
amplifier, the loudspeaker, and other elements which may be part of
the
amplifier·cable·loudspeaker circuit are treated.

Has anyone come across a loudspeaker protected by a positive tempco
resistor? These devices go from very low resistance to almost open
circuit over a very narrow temperature range.

Norm Strong

"Arny Krueger" wrote in message
...
"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to
show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in
the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Abstract: Loudspeaker cables are investigated to determine if they
exhibit
transmission-line characteristics. Lumped representations of cables
are
suggested with consideration of the effects cable parameters might
have on
the audio signal being transmitted. Interaction of the cable with
the
amplifier, the loudspeaker, and other elements which may be part of
the
amplifier·cable·loudspeaker circuit are treated.

Has anyone come across a loudspeaker protected by a positive tempco
resistor? These devices go from very low resistance to almost open
circuit over a very narrow temperature range.

Norm Strong

"Arny Krueger" wrote in message ...
"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Thanks, I'll have a look at this. I had the feeling that this must
have been examined by someone.

"Arny Krueger" wrote in message ...
"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Thanks, I'll have a look at this. I had the feeling that this must
have been examined by someone.

"Arny Krueger" wrote in message ...
"Isaac Wingfield" wrote in message


The time constant of the nonlinearity of a fuse is too long to show
up during a cycle of any audible frequency.

The classic Greiner JAES article found a fair amount of nonlinear
distortion using typical-valued quick blow fuses and test signals in the
audio range.

Amplifier·Loudspeaker Interfacing 637611 bytes (CD aes4)
Author(s): Greiner, R. A.
Publication: JAES Volume 28 Number 5 pp. 310·315; May 1980

Thanks, I'll have a look at this. I had the feeling that this must
have been examined by someone.