[jakdedert]

I know, I know...but for $9 in good shape at the thrift store, I figured
I couldn't go wrong. No way to test, but the surrounds were in
excellent condition; so I figured at least the woofers alone were worth
$4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In
addition to the minimal x-over components (resister and cap in series
with the tweeter) was a #561 automotive 'festoon' style lamp in series
with the tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm
is a roughly 12 watt unit with apprx. 1000 hours rated life. Did it
'fuse', or just wear out?

Strange stuff, this Bose....

jak

[gareth magennis]

"jakdedert" wrote in message
. ..
I know, I know...but for $9 in good shape at the thrift store, I figured I
couldn't go wrong. No way to test, but the surrounds were in excellent
condition; so I figured at least the woofers alone were worth $4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In addition
to the minimal x-over components (resister and cap in series with the
tweeter) was a #561 automotive 'festoon' style lamp in series with the
tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm is
a roughly 12 watt unit with apprx. 1000 hours rated life. Did it 'fuse',
or just wear out?

Strange stuff, this Bose....

jak



I would not bypass the bulb as the crossover is designed for the bulb in
place and you risk blowing the tweeters. The bulb has a significant
resistance compared with that of the tweeter.

Third party replacement is usually trial and error. Peavey speakers around
the 300 to 400 Watt mark use something like 24 volt truck bulbs, smaller
speakers may be using 12 volt ones, some JBL speakers higher rated bulbs.

In my experience, life is too short to be faffing around trying to find an
equivalent, and a phone call to Bose, Peavey, JBL, etc, will usually get you
the correct bulb with minimal effort and not a huge dent in your bank
balance.
And with the time you save you can be doing something much more pleasurable
instead. (So long as you dont spend it grumbling about having to pay X
dollars for a 10 cent light bulb .........)



Gareth.

[Kevin McMurtrie[_2_]]

In article ,
jakdedert wrote:

I know, I know...but for $9 in good shape at the thrift store, I figured
I couldn't go wrong. No way to test, but the surrounds were in
excellent condition; so I figured at least the woofers alone were worth
$4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In
addition to the minimal x-over components (resister and cap in series
with the tweeter) was a #561 automotive 'festoon' style lamp in series
with the tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm
is a roughly 12 watt unit with apprx. 1000 hours rated life. Did it
'fuse', or just wear out?

Strange stuff, this Bose....

jak

Light bulbs are surprisingly good current regulators. Small 12V 15W
bulbs have about 0.7 Ohms cold resistance and a current limit of about
1.2A. This and their slow changes in resistance makes them excellent
speaker protectors.

It's OK to bypass the bulb if the speakers aren't worth protecting. Or
you can just buy a pack of these bulbs at a hardware store for $1.
Since the lighting quality and life of the bulb doesn't matter one bit,
speakers usually have the very cheapest bulbs protecting them.

--
Google is a pro-spamming service. I will not see your reply if you use Google.

[Mr.T]

"jakdedert" wrote in message
. ..
is a roughly 12 watt unit with apprx. 1000 hours rated life. Did it
'fuse', or just wear out?

The 1000 hour life is of course at rated wattage, which is a fairly rare
event when used as a speaker protector. So almost certainly it did what it
was supposed to do and protect the tweeter.

Strange stuff, this Bose....

Absolutely, but not necessarily because of the globe :-)

MrT.

[Chronic Philharmonic]

"Mr.T" MrT@home wrote in message
u...

"jakdedert" wrote in message
. ..
is a roughly 12 watt unit with apprx. 1000 hours rated life. Did it
'fuse', or just wear out?

The 1000 hour life is of course at rated wattage, which is a fairly rare
event when used as a speaker protector. So almost certainly it did what it
was supposed to do and protect the tweeter.

Wow... Can you imagine ordinary listenable program material burning out that
light? The amp must have broken into oscillation or something.

[Mr.T]

"Chronic Philharmonic" wrote in message
...
The 1000 hour life is of course at rated wattage, which is a fairly rare
event when used as a speaker protector. So almost certainly it did what
it
was supposed to do and protect the tweeter.

Wow... Can you imagine ordinary listenable program material burning out
that
light? The amp must have broken into oscillation or something.

Nope, I can well imagine someone at a party turning it up that far. Happens
all the time, which is why the thing is there in the first place.
But yes, slightly lesser morons would turn it down before the globe actually
blew. Of course if the manufacturers weren't trying to hide their speakers
deficiencies, they would put the globe on display, and call it an overload
light, so the head bangers actually knew it was time to turn it down. That
would of course rely on the user interpreting the difference between a
slight glow and full brilliance, something the manufacturers don't think the
users can manage. Besides some manufacturers rely on income from repairs,
rather than a reputation for not needing them.

A faulty amp is a possibility of course, but less likely in this case IMO.
The far more common amp problem for speakers is a blown output stage putting
DC on the speakers, which of course is a problem for the woofers, not
tweeters.

MrT.

[Trevor Wilson[_2_]]

"jakdedert" wrote in message
. ..
I know, I know...but for $9 in good shape at the thrift store, I figured I
couldn't go wrong. No way to test, but the surrounds were in excellent
condition; so I figured at least the woofers alone were worth $4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In addition
to the minimal x-over components (resister and cap in series with the
tweeter) was a #561 automotive 'festoon' style lamp in series with the
tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm is
a roughly 12 watt unit with apprx. 1000 hours rated life. Did it 'fuse',
or just wear out?

Strange stuff, this Bose....


**Just whack a 070 PolyswitchT in place of the lamp you'll be sweet. There
might be a slightly noticeable increase in HF, but I doubt it. The
Polyswitch will last a very long time.


--
Trevor Wilson
www.rageaudio.com.au

[Eeyore]

jakdedert wrote:

I know, I know...but for $9 in good shape at the thrift store, I figured
I couldn't go wrong. No way to test, but the surrounds were in
excellent condition; so I figured at least the woofers alone were worth
$4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In
addition to the minimal x-over components (resister and cap in series
with the tweeter) was a #561 automotive 'festoon' style lamp in series
with the tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm
is a roughly 12 watt unit with apprx. 1000 hours rated life. Did it
'fuse', or just wear out?

Strange stuff, this Bose....

The use of lamp bulbs to protect tweeters is a well adopted trick. Many pro
units do it too.

I'd replace with same. It'll only blow when overdriven and save the tweets.

Graham

[Eeyore]

Gareth Magennis wrote:

"jakdedert" wrote

I know, I know...but for $9 in good shape at the thrift store, I figured I
couldn't go wrong. No way to test, but the surrounds were in excellent
condition; so I figured at least the woofers alone were worth $4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In addition
to the minimal x-over components (resister and cap in series with the
tweeter) was a #561 automotive 'festoon' style lamp in series with the
tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm is
a roughly 12 watt unit with apprx. 1000 hours rated life. Did it 'fuse',
or just wear out?

Strange stuff, this Bose....


I would not bypass the bulb as the crossover is designed for the bulb in
place and you risk blowing the tweeters. The bulb has a significant
resistance compared with that of the tweeter.

Third party replacement is usually trial and error. Peavey speakers around
the 300 to 400 Watt mark use something like 24 volt truck bulbs,

Exactly what I fit too with wattage varying with x'over freq. EV do it too even
for some 12" units.

smaller speakers may be using 12 volt ones, some JBL speakers higher rated
bulbs.

I've seen JBL get it totally wrong in their JRX series. The tweeter protects the
bulbs.

Graham

[Eeyore]

Kevin McMurtrie wrote:

It's OK to bypass the bulb if the speakers aren't worth protecting.

Although they'll be slightly brighter if you do.

Graham

[Eeyore]

Kevin McMurtrie wrote:

Since the lighting quality and life of the bulb doesn't matter one bit,
speakers usually have the very cheapest bulbs protecting them.

You should see the price of those 55W 24V truck headlight bulbs !

Graham

[Eeyore]

Chronic Philharmonic wrote:

"Mr.T" MrT@home wrote
"jakdedert" wrote

is a roughly 12 watt unit with apprx. 1000 hours rated life. Did it
'fuse', or just wear out?

The 1000 hour life is of course at rated wattage, which is a fairly rare
event when used as a speaker protector. So almost certainly it did what it
was supposed to do and protect the tweeter.

Wow... Can you imagine ordinary listenable program material burning out that
light? The amp must have broken into oscillation or something.

It happens in live sound rigs often enough to be an occasional nuisance. That's
why I keep a stock now.

21W 24V and 55W 24V. Somewhat higher powers than the Bose though !

Graham

[Eeyore]

"Mr.T" wrote:

"Chronic Philharmonic" wrote

The 1000 hour life is of course at rated wattage, which is a fairly rare
event when used as a speaker protector. So almost certainly it did what
it was supposed to do and protect the tweeter.

Wow... Can you imagine ordinary listenable program material burning out
that light? The amp must have broken into oscillation or something.

Nope, I can well imagine someone at a party turning it up that far. Happens
all the time, which is why the thing is there in the first place.

Highly likely.

Graham

[Eeyore]

Trevor Wilson wrote:

"jakdedert" wrote in message

I know, I know...but for $9 in good shape at the thrift store, I figured I
couldn't go wrong. No way to test, but the surrounds were in excellent
condition; so I figured at least the woofers alone were worth $4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In addition
to the minimal x-over components (resister and cap in series with the
tweeter) was a #561 automotive 'festoon' style lamp in series with the
tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm is
a roughly 12 watt unit with apprx. 1000 hours rated life. Did it 'fuse',
or just wear out?

Strange stuff, this Bose....

**Just whack a 070 PolyswitchT in place of the lamp you'll be sweet. There
might be a slightly noticeable increase in HF, but I doubt it. The
Polyswitch will last a very long time.

The Polyswitch guys actually do/did an app note on tweeter/driver protection
inluding using bulbs as well ! Polyswitches on their own tend not to 'reset'
very well you see, whereas bulbs do.

Graham

[Kevin McMurtrie[_2_]]

In article ,
Eeyore wrote:

Kevin McMurtrie wrote:

It's OK to bypass the bulb if the speakers aren't worth protecting.

Although they'll be slightly brighter if you do.

Graham

LOL!

--
Google is a pro-spamming service. I will not see your reply if you use Google.

[Kevin McMurtrie[_2_]]

In article ,
Eeyore wrote:

Kevin McMurtrie wrote:

Since the lighting quality and life of the bulb doesn't matter one bit,
speakers usually have the very cheapest bulbs protecting them.

You should see the price of those 55W 24V truck headlight bulbs !

Graham

All bets are off for pro-gear

A comparable naked projector bulb would regulate fine if you could find
a brand that has solderable leads. They're usually an alloy that
doesn't conduct at low voltages and resists soldering because of a
durable oxide layer.

--
Google is a pro-spamming service. I will not see your reply if you use Google.

[Eeyore]

Kevin McMurtrie wrote:

Eeyore wrote:
Kevin McMurtrie wrote:

Since the lighting quality and life of the bulb doesn't matter one bit,
speakers usually have the very cheapest bulbs protecting them.

You should see the price of those 55W 24V truck headlight bulbs !

All bets are off for pro-gear

A comparable naked projector bulb would regulate fine if you could find
a brand that has solderable leads. They're usually an alloy that
doesn't conduct at low voltages and resists soldering because of a
durable oxide layer.

Sylvania actually make a specialist range of bulbs for this purpose as used by JBL
and Eminence in their crossovers to name a couple I know of

http://www.sylvaniaautocatalog.com/s.../pro_other.asp

See HPCCR.

Graham

[Trevor Wilson[_2_]]

"Eeyore" wrote in message
...


Trevor Wilson wrote:

"jakdedert" wrote in message

I know, I know...but for $9 in good shape at the thrift store, I figured
I
couldn't go wrong. No way to test, but the surrounds were in excellent
condition; so I figured at least the woofers alone were worth $4.50
each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In
addition
to the minimal x-over components (resister and cap in series with the
tweeter) was a #561 automotive 'festoon' style lamp in series with the
tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm
is
a roughly 12 watt unit with apprx. 1000 hours rated life. Did it 'fuse',
or just wear out?

Strange stuff, this Bose....

**Just whack a 070 PolyswitchT in place of the lamp you'll be sweet.
There
might be a slightly noticeable increase in HF, but I doubt it. The
Polyswitch will last a very long time.

The Polyswitch guys actually do/did an app note on tweeter/driver
protection
inluding using bulbs as well ! Polyswitches on their own tend not to
'reset'
very well you see, whereas bulbs do.

**Incorrect. PolyswitchesT 'reset' just fine. They simply require the user
to reduce levels going to the driver/s. Best of all, is that if the
PolyswitchT is used within it's specs, it will not readily fail. Lamps WILL
fail. One needs to understand how PolyswitchesT work, before using them.

For the record: I've used PolyswitchesT in *A LOT* of speaker systems, since
1985. I've never had to replace a PolyswitchT, or a tweeter in a system
which has been so modified. OTOH, I have seen failed PolyswitchesT in some
equipment. They can be destroyed by over-Voltage. It's a pretty rare event
though.


--
Trevor Wilson
www.rageaudio.com.au

[Eeyore]

Trevor Wilson wrote:

"Eeyore" wrote in message
Trevor Wilson wrote:

**Just whack a 070 PolyswitchT in place of the lamp you'll be sweet.
There might be a slightly noticeable increase in HF, but I doubt it. The
Polyswitch will last a very long time.

The Polyswitch guys actually do/did an app note on tweeter/driver
protection inluding using bulbs as well ! Polyswitches on their own tend not
to
'reset' very well you see, whereas bulbs do.

**Incorrect. PolyswitchesT 'reset' just fine. They simply require the user
to reduce levels going to the driver/s.

That's the whole point ! The user rarely does that.

Get the app note !

Graham

[gareth magennis]

"Eeyore" wrote in message
...


Kevin McMurtrie wrote:

Eeyore wrote:
Kevin McMurtrie wrote:

Since the lighting quality and life of the bulb doesn't matter one
bit,
speakers usually have the very cheapest bulbs protecting them.

You should see the price of those 55W 24V truck headlight bulbs !

All bets are off for pro-gear

A comparable naked projector bulb would regulate fine if you could find
a brand that has solderable leads. They're usually an alloy that
doesn't conduct at low voltages and resists soldering because of a
durable oxide layer.

Sylvania actually make a specialist range of bulbs for this purpose as
used by JBL
and Eminence in their crossovers to name a couple I know of

http://www.sylvaniaautocatalog.com/s.../pro_other.asp

See HPCCR.

Graham





Wharfedale use these too. Some have a Red Dot and are stocked as such. It
would seem these are chosen as part of the design. They don't just fit some
truck bulb they bought at Halfords.

Hence my prior suggestion of going to the manufacturer to get the bulb
intended for the application.



Gareth.

[Trevor Wilson[_2_]]

"Eeyore" wrote in message
...


Trevor Wilson wrote:

"Eeyore" wrote in message
Trevor Wilson wrote:

**Just whack a 070 PolyswitchT in place of the lamp you'll be sweet.
There might be a slightly noticeable increase in HF, but I doubt it.
The
Polyswitch will last a very long time.

The Polyswitch guys actually do/did an app note on tweeter/driver
protection inluding using bulbs as well ! Polyswitches on their own
tend not
to
'reset' very well you see, whereas bulbs do.

**Incorrect. PolyswitchesT 'reset' just fine. They simply require the
user
to reduce levels going to the driver/s.

That's the whole point ! The user rarely does that.

**Doesn't bother me in the slightest. The user stops destroying tweeters.
That is the aim.


Get the app note !

**I'll look at it sometime.


--
Trevor Wilson
www.rageaudio.com.au

[Eeyore]

Trevor Wilson wrote:

"Eeyore" wrote
Trevor Wilson wrote:
"Eeyore" wrote
Trevor Wilson wrote:

**Just whack a 070 PolyswitchT in place of the lamp you'll be sweet.
There might be a slightly noticeable increase in HF, but I doubt it.
The Polyswitch will last a very long time.

The Polyswitch guys actually do/did an app note on tweeter/driver
protection inluding using bulbs as well ! Polyswitches on their own
tend not to 'reset' very well you see, whereas bulbs do.

**Incorrect. PolyswitchesT 'reset' just fine. They simply require the
user to reduce levels going to the driver/s.

That's the whole point ! The user rarely does that.

**Doesn't bother me in the slightest. The user stops destroying tweeters.
That is the aim.

Well that is an advantage ! ;~)


Get the app note !

**I'll look at it sometime.

It may be online now. Very likely actually.

Graham

[mariarayan]

Originally Posted by jakdedert

I know, I know...but for $9 in good shape at the thrift store, I figured
I couldn't go wrong. No way to test, but the surrounds were in
excellent condition; so I figured at least the woofers alone were worth
$4.50 each.

Brought them home, hooked 'em up, they made noise...so far so good, but
where were the highs? AWOL...crap, blown tweets! Not so fast....

Tested the tweeters with 9v battery--fine. Okay, time to open the box.
Pulled the surprisingly flimsy woofer from the 1/2" MDF box In
addition to the minimal x-over components (resister and cap in series
with the tweeter) was a #561 automotive 'festoon' style lamp in series
with the tweet. Shorting that brought back highs.

Now considering this was a series limiter, should I replace it, or just
bypass? The lamp
http://www.bulbtown.com/561_MINIATURE_BULB_RIGID_LOOP_BASE_p/561.htm
is a roughly 12 watt unit with apprx. 1000 hours rated life. Did it
'fuse', or just wear out?

Strange stuff, this Bose....

jak

yeah i think Light bulbs are surprisingly good current regulators.