In article lid writes:

How do most power supplies handle that all too possible situation of
(a) an unintentional fault causing a short between the earth and signal
pins
(b) an intentional situation of connecting an unbalanced source that has
pin 2 connected to ground, as is standard practice but which results in
phantom shorted to earth?

The standard phantom power circuit puts a 6800 ohm resistor in series
with the voltage going to each signal pin of the XLR connector.
Shorting one (or even both) pins to Pin 1 causes a current of
48V/6800ê or a fraction over 7 mA. That's just a little more than the
worst case microphone. Assuming the power supply is "stiff" enough,
this won't cause a change in the phantom power supplied to any other
mics fed from the same supply.

I was working on a patch panel the other day. The desk was powered up and
had phantom on. Every time I touched my earthed soldering iron to the
signal pins there was a nice little blue spark from the phantom power.

It was only a tiny spark, hopefully. No damage done, probably, but why
not turn off the phantom power? Or use an ungrounded soldering iron?

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article lid writes:

How do most power supplies handle that all too possible situation of
(a) an unintentional fault causing a short between the earth and signal
pins
(b) an intentional situation of connecting an unbalanced source that has
pin 2 connected to ground, as is standard practice but which results in
phantom shorted to earth?

The standard phantom power circuit puts a 6800 ohm resistor in series
with the voltage going to each signal pin of the XLR connector.
Shorting one (or even both) pins to Pin 1 causes a current of
48V/6800ê or a fraction over 7 mA. That's just a little more than the
worst case microphone. Assuming the power supply is "stiff" enough,
this won't cause a change in the phantom power supplied to any other
mics fed from the same supply.

I was working on a patch panel the other day. The desk was powered up and
had phantom on. Every time I touched my earthed soldering iron to the
signal pins there was a nice little blue spark from the phantom power.

It was only a tiny spark, hopefully. No damage done, probably, but why
not turn off the phantom power? Or use an ungrounded soldering iron?

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article lid writes:

How do most power supplies handle that all too possible situation of
(a) an unintentional fault causing a short between the earth and signal
pins
(b) an intentional situation of connecting an unbalanced source that has
pin 2 connected to ground, as is standard practice but which results in
phantom shorted to earth?

The standard phantom power circuit puts a 6800 ohm resistor in series
with the voltage going to each signal pin of the XLR connector.
Shorting one (or even both) pins to Pin 1 causes a current of
48V/6800ê or a fraction over 7 mA. That's just a little more than the
worst case microphone. Assuming the power supply is "stiff" enough,
this won't cause a change in the phantom power supplied to any other
mics fed from the same supply.

I was working on a patch panel the other day. The desk was powered up and
had phantom on. Every time I touched my earthed soldering iron to the
signal pins there was a nice little blue spark from the phantom power.

It was only a tiny spark, hopefully. No damage done, probably, but why
not turn off the phantom power? Or use an ungrounded soldering iron?

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article in rec.audio.pro on Fri,
24 Sep 2004 19:46:58 GMT, Logan Shaw says...

By the way, as for why it's 48V, I think that has to do with
a compromise.

In article lid writes:

No, like the 600 ohms impedance, 48V comes to us from telephone
technology. That is the voltage that phantom power on your telephone line
uses.

It is a compromise of sorts. In some countries in Europe, 48V is the
highest voltage they'll allow for a temporary (not-in-conduit)
installation. Imagine having to run your PA snake through conduit to
set up your system in a club.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article in rec.audio.pro on Fri,
24 Sep 2004 19:46:58 GMT, Logan Shaw says...

By the way, as for why it's 48V, I think that has to do with
a compromise.

In article lid writes:

No, like the 600 ohms impedance, 48V comes to us from telephone
technology. That is the voltage that phantom power on your telephone line
uses.

It is a compromise of sorts. In some countries in Europe, 48V is the
highest voltage they'll allow for a temporary (not-in-conduit)
installation. Imagine having to run your PA snake through conduit to
set up your system in a club.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article in rec.audio.pro on Fri,
24 Sep 2004 19:46:58 GMT, Logan Shaw says...

By the way, as for why it's 48V, I think that has to do with
a compromise.

In article lid writes:

No, like the 600 ohms impedance, 48V comes to us from telephone
technology. That is the voltage that phantom power on your telephone line
uses.

It is a compromise of sorts. In some countries in Europe, 48V is the
highest voltage they'll allow for a temporary (not-in-conduit)
installation. Imagine having to run your PA snake through conduit to
set up your system in a club.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article znr1096063987k@trad, (Mike Rivers)
wrote:

In article in rec.audio.pro on Fri,
24 Sep 2004 19:46:58 GMT, Logan Shaw says...

By the way, as for why it's 48V, I think that has to do with
a compromise.

In article
lid writes:

No, like the 600 ohms impedance, 48V comes to us from telephone
technology. That is the voltage that phantom power on your telephone line
uses.

It is a compromise of sorts. In some countries in Europe, 48V is the
highest voltage they'll allow for a temporary (not-in-conduit)
installation. Imagine having to run your PA snake through conduit to
set up your system in a club.

many of my outdoor(jam band festival in the feild sites) venues requrie
me to pull the snake through underground conduit, often 12 inch pvc pipe
George

In article znr1096063987k@trad, (Mike Rivers)
wrote:

In article in rec.audio.pro on Fri,
24 Sep 2004 19:46:58 GMT, Logan Shaw says...

By the way, as for why it's 48V, I think that has to do with
a compromise.

In article
lid writes:

No, like the 600 ohms impedance, 48V comes to us from telephone
technology. That is the voltage that phantom power on your telephone line
uses.

It is a compromise of sorts. In some countries in Europe, 48V is the
highest voltage they'll allow for a temporary (not-in-conduit)
installation. Imagine having to run your PA snake through conduit to
set up your system in a club.

many of my outdoor(jam band festival in the feild sites) venues requrie
me to pull the snake through underground conduit, often 12 inch pvc pipe
George

In article znr1096063987k@trad, (Mike Rivers)
wrote:

In article in rec.audio.pro on Fri,
24 Sep 2004 19:46:58 GMT, Logan Shaw says...

By the way, as for why it's 48V, I think that has to do with
a compromise.

In article
lid writes:

No, like the 600 ohms impedance, 48V comes to us from telephone
technology. That is the voltage that phantom power on your telephone line
uses.

It is a compromise of sorts. In some countries in Europe, 48V is the
highest voltage they'll allow for a temporary (not-in-conduit)
installation. Imagine having to run your PA snake through conduit to
set up your system in a club.

many of my outdoor(jam band festival in the feild sites) venues requrie
me to pull the snake through underground conduit, often 12 inch pvc pipe
George

(Don Pearce) wrote in message ...
On 24 Sep 2004 10:44:05 -0700, (Neil) wrote:

Hello everyone,

I hope someone out there can answer my question, and I hope it doesn't
come across as too naieve!.

The question is regarding Phantom Power. At college, there is a 32
track mixing console, each track has an individual 'phantom power'
switch. The question arose in class that if every single track on the
mixer had phantom power enabled and phantom power runs at +48V, would
this equate to 1536V??, or isn't it as simple as that?. I realise most
mic's wouldn't draw 48V of current, but if that's the case, why is
phantom power set at 48V if the microphones don't need that much to
operate?.

I've searched for an answer to this question on the web, but I've
found no answers. Hope someone can help me!.

Thanks in advance,
Neil.

This is tricky - first we need to sort out your terminology a bit. 48V
isn't a current - it is a voltage. It is available to any mic that
needs it, but it is wired in a mode called parallel - that is it
doesn't add up for every mic, it is just 48V - no more than that. On
each mic channel it is fed to the mic through a pair of resistors of
about 6000 ohms (3000 ohms equivalent) so any single mic can take up
to 48/3000 or 0.016 amps (16mA). That is plenty for even the most
demanding phantom mic - most take much less. SOme need more, and they
come with their own power supply.

But the point is that all microphones are guaranteed to work off that
voltage and resistance combination, but most don't need that much.

As for the desk, if you have, say 24 mic channels, then the 48V power
supply must be able to supply 24 x .016 amps, or roughly half an amp.
So you see it is the amps, not the volts, that build up as you add
more microphones.

d
Pearce Consulting
http://www.pearce.uk.com



Thanks very much for the reply. The reason I couldn't find out the
answer earlier is because the question is redundant! I had a feeling
it was a silly question, but I appreciate the replies.

Neil.

(Don Pearce) wrote in message ...
On 24 Sep 2004 10:44:05 -0700, (Neil) wrote:

Hello everyone,

I hope someone out there can answer my question, and I hope it doesn't
come across as too naieve!.

The question is regarding Phantom Power. At college, there is a 32
track mixing console, each track has an individual 'phantom power'
switch. The question arose in class that if every single track on the
mixer had phantom power enabled and phantom power runs at +48V, would
this equate to 1536V??, or isn't it as simple as that?. I realise most
mic's wouldn't draw 48V of current, but if that's the case, why is
phantom power set at 48V if the microphones don't need that much to
operate?.

I've searched for an answer to this question on the web, but I've
found no answers. Hope someone can help me!.

Thanks in advance,
Neil.

This is tricky - first we need to sort out your terminology a bit. 48V
isn't a current - it is a voltage. It is available to any mic that
needs it, but it is wired in a mode called parallel - that is it
doesn't add up for every mic, it is just 48V - no more than that. On
each mic channel it is fed to the mic through a pair of resistors of
about 6000 ohms (3000 ohms equivalent) so any single mic can take up
to 48/3000 or 0.016 amps (16mA). That is plenty for even the most
demanding phantom mic - most take much less. SOme need more, and they
come with their own power supply.

But the point is that all microphones are guaranteed to work off that
voltage and resistance combination, but most don't need that much.

As for the desk, if you have, say 24 mic channels, then the 48V power
supply must be able to supply 24 x .016 amps, or roughly half an amp.
So you see it is the amps, not the volts, that build up as you add
more microphones.

d
Pearce Consulting
http://www.pearce.uk.com



Thanks very much for the reply. The reason I couldn't find out the
answer earlier is because the question is redundant! I had a feeling
it was a silly question, but I appreciate the replies.

Neil.

(Don Pearce) wrote in message ...
On 24 Sep 2004 10:44:05 -0700, (Neil) wrote:

Hello everyone,

I hope someone out there can answer my question, and I hope it doesn't
come across as too naieve!.

The question is regarding Phantom Power. At college, there is a 32
track mixing console, each track has an individual 'phantom power'
switch. The question arose in class that if every single track on the
mixer had phantom power enabled and phantom power runs at +48V, would
this equate to 1536V??, or isn't it as simple as that?. I realise most
mic's wouldn't draw 48V of current, but if that's the case, why is
phantom power set at 48V if the microphones don't need that much to
operate?.

I've searched for an answer to this question on the web, but I've
found no answers. Hope someone can help me!.

Thanks in advance,
Neil.

This is tricky - first we need to sort out your terminology a bit. 48V
isn't a current - it is a voltage. It is available to any mic that
needs it, but it is wired in a mode called parallel - that is it
doesn't add up for every mic, it is just 48V - no more than that. On
each mic channel it is fed to the mic through a pair of resistors of
about 6000 ohms (3000 ohms equivalent) so any single mic can take up
to 48/3000 or 0.016 amps (16mA). That is plenty for even the most
demanding phantom mic - most take much less. SOme need more, and they
come with their own power supply.

But the point is that all microphones are guaranteed to work off that
voltage and resistance combination, but most don't need that much.

As for the desk, if you have, say 24 mic channels, then the 48V power
supply must be able to supply 24 x .016 amps, or roughly half an amp.
So you see it is the amps, not the volts, that build up as you add
more microphones.

d
Pearce Consulting
http://www.pearce.uk.com



Thanks very much for the reply. The reason I couldn't find out the
answer earlier is because the question is redundant! I had a feeling
it was a silly question, but I appreciate the replies.

Neil.

On 24 Sep 2004 21:05:57 -0400, Mike Rivers wrote:

It was only a tiny spark, hopefully. No damage done, probably, but why
not turn off the phantom power? Or use an ungrounded soldering iron?

Why can't people shut off the switch at the breaker when working with
connected devices, but turning off the pahntom power is a good start, if
you trust your device more than the breaker...
Also, if you don't use a grounded iron, just remember that you might be
grounded...which is fine if you shut off the power, and there's no
undischarged capacitors lurking...

On 24 Sep 2004 21:05:57 -0400, Mike Rivers wrote:

It was only a tiny spark, hopefully. No damage done, probably, but why
not turn off the phantom power? Or use an ungrounded soldering iron?

Why can't people shut off the switch at the breaker when working with
connected devices, but turning off the pahntom power is a good start, if
you trust your device more than the breaker...
Also, if you don't use a grounded iron, just remember that you might be
grounded...which is fine if you shut off the power, and there's no
undischarged capacitors lurking...

On 24 Sep 2004 21:05:57 -0400, Mike Rivers wrote:

It was only a tiny spark, hopefully. No damage done, probably, but why
not turn off the phantom power? Or use an ungrounded soldering iron?

Why can't people shut off the switch at the breaker when working with
connected devices, but turning off the pahntom power is a good start, if
you trust your device more than the breaker...
Also, if you don't use a grounded iron, just remember that you might be
grounded...which is fine if you shut off the power, and there's no
undischarged capacitors lurking...

On 25 Sep 2004 00:52:07 GMT, ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Scott Fraser

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

On 25 Sep 2004 00:52:07 GMT, ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Scott Fraser

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

On 25 Sep 2004 00:52:07 GMT, ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Scott Fraser

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

When I went to College/ University, you were expected to know a little bit about
the subject in advance of being allowed admission.

My UK 'A level' Physics course at school included plenty of electricity /
electronics theory. I can even recall the discussion of photo-electric emission
( energy states in electron orbits and stuff like that ).


Graham

ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

When I went to College/ University, you were expected to know a little bit about
the subject in advance of being allowed admission.

My UK 'A level' Physics course at school included plenty of electricity /
electronics theory. I can even recall the discussion of photo-electric emission
( energy states in electron orbits and stuff like that ).


Graham

ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

When I went to College/ University, you were expected to know a little bit about
the subject in advance of being allowed admission.

My UK 'A level' Physics course at school included plenty of electricity /
electronics theory. I can even recall the discussion of photo-electric emission
( energy states in electron orbits and stuff like that ).


Graham

KingMe wrote:

On 25 Sep 2004 00:52:07 GMT, ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Scott Fraser

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

In the UK it's been very badly dumbed down. When I went to Uni, probably no more
that 10% of the population did so. It's now 30% with a target of 50% !

I don't think you need to be a genius to see that means letting in those who really
aren't up to the former grade and it shows.

A lecturer I know ( who's involved in a pro-audio course as it happens ) admitted
that they've had to dumb down the content in order to attract students, especially
when it's a course involving real brain work like electronics related stuff.


Graham

KingMe wrote:

On 25 Sep 2004 00:52:07 GMT, ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Scott Fraser

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

In the UK it's been very badly dumbed down. When I went to Uni, probably no more
that 10% of the population did so. It's now 30% with a target of 50% !

I don't think you need to be a genius to see that means letting in those who really
aren't up to the former grade and it shows.

A lecturer I know ( who's involved in a pro-audio course as it happens ) admitted
that they've had to dumb down the content in order to attract students, especially
when it's a course involving real brain work like electronics related stuff.


Graham

KingMe wrote:

On 25 Sep 2004 00:52:07 GMT, ScotFraser wrote:

Do you plan a career in pro-audio or the dole queue ? If the former, I
suggest you go learn something about the fundamentals. BRBR

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Scott Fraser

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

In the UK it's been very badly dumbed down. When I went to Uni, probably no more
that 10% of the population did so. It's now 30% with a target of 50% !

I don't think you need to be a genius to see that means letting in those who really
aren't up to the former grade and it shows.

A lecturer I know ( who's involved in a pro-audio course as it happens ) admitted
that they've had to dumb down the content in order to attract students, especially
when it's a course involving real brain work like electronics related stuff.


Graham

Pooh Bear wrote:
When I went to College/ University, you were expected to know a little bit about
the subject in advance of being allowed admission.

Oh yeah, I can definitely remember that scenario. Bummer when it's a
required class that you have absolutely NO personal interest in. (In
my own case, that was Probability I[1], although for various people
it can be English, or Government, or a wide variety of other things.)

- Logan

[1] I swear the only thing that saved me in that case was the marketing
department of The Coca-Cola Company. You see, they had this "one
free with six" promotion at the time, which basically meant that
when you got a Coke from the soda machine in the lab, you had a
1/6 chance of winning another Coke. Now, I wasn't taking probability
that semester, but my friend Omar was, so I kept pestering him
with questions, because I was sure that if you get a free Coke,
it *also* has a 1/6 chance of winning, so logically that means
that as you approach buying an infinite number of Cokes (not an
impossible proposition for a college student, mind you), that
your total earnings would be more than 1/6. Because, in 1/6 of
the cases, you'd win, and you'd have another 1/6 chance of winning
something further. Omar wasn't sure what I was getting at
(although I am used to that), so I just pondered it for a whole
semester and eventually determined that, in the same way that
1/2 + 1/4 + 1/8 + 1/16 + ... = 1, it should be the case that
1/6 + 1/36 + 1/216 + ... = 1/5, so if you buy a huge number of
Cokes, then actually you get one free with FIVE, not six. Then,
as it turns out, the final exam in Probability I was really tough,
but one of the questions involved the Starship Enterprise and a
wormhole, but conceptually it was exactly the same thing as the
Coca-Cola question, so I just answered it right away with no
trouble, whereas most of the rest of the class could be heard
after the final exam saying things like, "Man, what was that Star
Trek problem about? I had NO IDEA how to answer that one!"
But it counted for more 10% or more of the exam, so I am convinced
that through either pure luck or through divine providence, I was
able to actually pass the class and finally finish college[2].

[2] Yes, I *do* realize just how long the previous footnote is.
I think there is AT LEAST a 1/6 probability that it's a
personal record.

Pooh Bear wrote:
When I went to College/ University, you were expected to know a little bit about
the subject in advance of being allowed admission.

Oh yeah, I can definitely remember that scenario. Bummer when it's a
required class that you have absolutely NO personal interest in. (In
my own case, that was Probability I[1], although for various people
it can be English, or Government, or a wide variety of other things.)

- Logan

[1] I swear the only thing that saved me in that case was the marketing
department of The Coca-Cola Company. You see, they had this "one
free with six" promotion at the time, which basically meant that
when you got a Coke from the soda machine in the lab, you had a
1/6 chance of winning another Coke. Now, I wasn't taking probability
that semester, but my friend Omar was, so I kept pestering him
with questions, because I was sure that if you get a free Coke,
it *also* has a 1/6 chance of winning, so logically that means
that as you approach buying an infinite number of Cokes (not an
impossible proposition for a college student, mind you), that
your total earnings would be more than 1/6. Because, in 1/6 of
the cases, you'd win, and you'd have another 1/6 chance of winning
something further. Omar wasn't sure what I was getting at
(although I am used to that), so I just pondered it for a whole
semester and eventually determined that, in the same way that
1/2 + 1/4 + 1/8 + 1/16 + ... = 1, it should be the case that
1/6 + 1/36 + 1/216 + ... = 1/5, so if you buy a huge number of
Cokes, then actually you get one free with FIVE, not six. Then,
as it turns out, the final exam in Probability I was really tough,
but one of the questions involved the Starship Enterprise and a
wormhole, but conceptually it was exactly the same thing as the
Coca-Cola question, so I just answered it right away with no
trouble, whereas most of the rest of the class could be heard
after the final exam saying things like, "Man, what was that Star
Trek problem about? I had NO IDEA how to answer that one!"
But it counted for more 10% or more of the exam, so I am convinced
that through either pure luck or through divine providence, I was
able to actually pass the class and finally finish college[2].

[2] Yes, I *do* realize just how long the previous footnote is.
I think there is AT LEAST a 1/6 probability that it's a
personal record.

Pooh Bear wrote:
When I went to College/ University, you were expected to know a little bit about
the subject in advance of being allowed admission.

Oh yeah, I can definitely remember that scenario. Bummer when it's a
required class that you have absolutely NO personal interest in. (In
my own case, that was Probability I[1], although for various people
it can be English, or Government, or a wide variety of other things.)

- Logan

[1] I swear the only thing that saved me in that case was the marketing
department of The Coca-Cola Company. You see, they had this "one
free with six" promotion at the time, which basically meant that
when you got a Coke from the soda machine in the lab, you had a
1/6 chance of winning another Coke. Now, I wasn't taking probability
that semester, but my friend Omar was, so I kept pestering him
with questions, because I was sure that if you get a free Coke,
it *also* has a 1/6 chance of winning, so logically that means
that as you approach buying an infinite number of Cokes (not an
impossible proposition for a college student, mind you), that
your total earnings would be more than 1/6. Because, in 1/6 of
the cases, you'd win, and you'd have another 1/6 chance of winning
something further. Omar wasn't sure what I was getting at
(although I am used to that), so I just pondered it for a whole
semester and eventually determined that, in the same way that
1/2 + 1/4 + 1/8 + 1/16 + ... = 1, it should be the case that
1/6 + 1/36 + 1/216 + ... = 1/5, so if you buy a huge number of
Cokes, then actually you get one free with FIVE, not six. Then,
as it turns out, the final exam in Probability I was really tough,
but one of the questions involved the Starship Enterprise and a
wormhole, but conceptually it was exactly the same thing as the
Coca-Cola question, so I just answered it right away with no
trouble, whereas most of the rest of the class could be heard
after the final exam saying things like, "Man, what was that Star
Trek problem about? I had NO IDEA how to answer that one!"
But it counted for more 10% or more of the exam, so I am convinced
that through either pure luck or through divine providence, I was
able to actually pass the class and finally finish college[2].

[2] Yes, I *do* realize just how long the previous footnote is.
I think there is AT LEAST a 1/6 probability that it's a
personal record.

On Fri, 24 Sep 2004 13:44:05 -0400, Neil wrote
(in article ) :

Hello everyone,

I hope someone out there can answer my question, and I hope it doesn't
come across as too naieve!.

The question is regarding Phantom Power. At college, there is a 32
track mixing console, each track has an individual 'phantom power'
switch. The question arose in class that if every single track on the
mixer had phantom power enabled and phantom power runs at +48V, would
this equate to 1536V??, or isn't it as simple as that?. I realise most
mic's wouldn't draw 48V of current, but if that's the case, why is
phantom power set at 48V if the microphones don't need that much to
operate?.

I've searched for an answer to this question on the web, but I've
found no answers. Hope someone can help me!.

Thanks in advance,
Neil.

Hi Neil,

As others may have mentioned, you need a slight tweek on your technology.
Voltage and current are different.

Ultimately, it's the combination of voltage and current (E x I = P) that
results in P (power). Some mics are more forgiving, and are able to run with
less than 48 VDC, providing enough current is there to supply the total
power.

The 48 VDC is voltage..and we assume that it's really 48 and is stabilized,
so adding more mics doesn't load the circuit down to something less than
48VDC.

The current part of the circuit should be large enough to feed all of the
mics. Different condenser mics have different power requirements. Some need
more mA (millamps) than others. Some console power supplies are not designed
to properly power all mics. The result is increased distortion and lower
headroom on the mics themselves.


Regards,

Ty Ford







-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

On Fri, 24 Sep 2004 13:44:05 -0400, Neil wrote
(in article ) :

Hello everyone,

I hope someone out there can answer my question, and I hope it doesn't
come across as too naieve!.

The question is regarding Phantom Power. At college, there is a 32
track mixing console, each track has an individual 'phantom power'
switch. The question arose in class that if every single track on the
mixer had phantom power enabled and phantom power runs at +48V, would
this equate to 1536V??, or isn't it as simple as that?. I realise most
mic's wouldn't draw 48V of current, but if that's the case, why is
phantom power set at 48V if the microphones don't need that much to
operate?.

I've searched for an answer to this question on the web, but I've
found no answers. Hope someone can help me!.

Thanks in advance,
Neil.

Hi Neil,

As others may have mentioned, you need a slight tweek on your technology.
Voltage and current are different.

Ultimately, it's the combination of voltage and current (E x I = P) that
results in P (power). Some mics are more forgiving, and are able to run with
less than 48 VDC, providing enough current is there to supply the total
power.

The 48 VDC is voltage..and we assume that it's really 48 and is stabilized,
so adding more mics doesn't load the circuit down to something less than
48VDC.

The current part of the circuit should be large enough to feed all of the
mics. Different condenser mics have different power requirements. Some need
more mA (millamps) than others. Some console power supplies are not designed
to properly power all mics. The result is increased distortion and lower
headroom on the mics themselves.


Regards,

Ty Ford







-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

In article writes:

many of my outdoor(jam band festival in the feild sites) venues requrie
me to pull the snake through underground conduit, often 12 inch pvc pipe

That's certainly an reasonable alternative to stringing it overhead.
Obviously they (and you) don't want it laying along the ground. Hope
they have the pipe installed already, or pay you well to install it.

I recall reading about a huge festival in California several years,
maybe the Us Festival, where they laid contuit, probably concrete
sewer pipe, that was large enough to crawl through without too much
contortion. They used it to get between the house console and the
stage without fighting through a sea of people.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

many of my outdoor(jam band festival in the feild sites) venues requrie
me to pull the snake through underground conduit, often 12 inch pvc pipe

That's certainly an reasonable alternative to stringing it overhead.
Obviously they (and you) don't want it laying along the ground. Hope
they have the pipe installed already, or pay you well to install it.

I recall reading about a huge festival in California several years,
maybe the Us Festival, where they laid contuit, probably concrete
sewer pipe, that was large enough to crawl through without too much
contortion. They used it to get between the house console and the
stage without fighting through a sea of people.


--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

Oh, I don't think it was a stupid question, I was just surprised that
he didn't get an immediate answer about the phantom power voltage, as
well as being corrected about voltage vs. current. I'm guessing that
he didn't get an answer in class and that's why he asked here.



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.

Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books

Oh, I don't think it was a stupid question, I was just surprised that
he didn't get an immediate answer about the phantom power voltage, as
well as being corrected about voltage vs. current. I'm guessing that
he didn't get an answer in class and that's why he asked here.



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article znr1096110202k@trad, (Mike Rivers)
wrote:

In article
writes:

many of my outdoor(jam band festival in the feild sites) venues requrie
me to pull the snake through underground conduit, often 12 inch pvc pipe

That's certainly an reasonable alternative to stringing it overhead.
Obviously they (and you) don't want it laying along the ground. Hope
they have the pipe installed already, or pay you well to install it.


yes they installed it
G

In article znr1096110202k@trad, (Mike Rivers)
wrote:

In article
writes:

many of my outdoor(jam band festival in the feild sites) venues requrie
me to pull the snake through underground conduit, often 12 inch pvc pipe

That's certainly an reasonable alternative to stringing it overhead.
Obviously they (and you) don't want it laying along the ground. Hope
they have the pipe installed already, or pay you well to install it.


yes they installed it
G

On 24 Sep 2004 10:44:05 -0700, in rec.audio.pro you wrote:

Hello everyone,

I hope someone out there can answer my question, and I hope it doesn't
come across as too naieve!.

The question is regarding Phantom Power. At college, there is a 32
track mixing console, each track has an individual 'phantom power'
switch. The question arose in class that if every single track on the
mixer had phantom power enabled and phantom power runs at +48V, would
this equate to 1536V??, or isn't it as simple as that?. I realise most
mic's wouldn't draw 48V of current, but if that's the case, why is
phantom power set at 48V if the microphones don't need that much to
operate?.

I've searched for an answer to this question on the web, but I've
found no answers. Hope someone can help me!.

Thanks in advance,
Neil.
Hi Neil

a good site is

http://www.microphone-data.com/library.asp



martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

On 24 Sep 2004 10:44:05 -0700, in rec.audio.pro you wrote:

Hello everyone,

I hope someone out there can answer my question, and I hope it doesn't
come across as too naieve!.

The question is regarding Phantom Power. At college, there is a 32
track mixing console, each track has an individual 'phantom power'
switch. The question arose in class that if every single track on the
mixer had phantom power enabled and phantom power runs at +48V, would
this equate to 1536V??, or isn't it as simple as that?. I realise most
mic's wouldn't draw 48V of current, but if that's the case, why is
phantom power set at 48V if the microphones don't need that much to
operate?.

I've searched for an answer to this question on the web, but I've
found no answers. Hope someone can help me!.

Thanks in advance,
Neil.
Hi Neil

a good site is

http://www.microphone-data.com/library.asp



martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

Mike Rivers wrote:

In article writes:


Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.


Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books


Oh, I don't think it was a stupid question, I was just surprised that
he didn't get an immediate answer about the phantom power voltage, as
well as being corrected about voltage vs. current. I'm guessing that
he didn't get an answer in class and that's why he asked here.


Bingo. The OP did say that they had been discussing it.

Mike Rivers wrote:

In article writes:


Might could be that's exactly why he's in college, which, last I heard, still
allowed questions to be asked.


Yeah, they're dumbed it down a lot, but there's still a thing as a stupid
question...the only thing I can say is better hit those books


Oh, I don't think it was a stupid question, I was just surprised that
he didn't get an immediate answer about the phantom power voltage, as
well as being corrected about voltage vs. current. I'm guessing that
he didn't get an answer in class and that's why he asked here.


Bingo. The OP did say that they had been discussing it.

I'm guessing that
he didn't get an answer in class and that's why he asked here.
BRBR

Yeah, unfortunately some self-certified superior being had to slam the kid for
not already knowing the answer to the question he was asking.

Scott Fraser