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Blowing Phantom Power

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Anonymous
February 8, 2005 9:14:27 PM

Archived from groups: rec.audio.pro (More info?)

Hi

I have a MXL990 condenser mic and a Behringer UB1202 mixer.
Everything was working fine with the phantom power.
I then made plugged in my shure sm57 while I still had the phantom power on
(MXL was unplugged at this point), and ever since, the phantom power doesn't
seem to work (although the LED is on)

Have I broken my mixers phantom power by plugging in another dynamic mic
while the phantom power was on?

I hope not :-)

Thanks for any assistance.

Mike


--
Check out my music!
http://www.bluemenagerie.co.uk

More about : blowing phantom power

Anonymous
February 8, 2005 9:14:28 PM

Archived from groups: rec.audio.pro (More info?)

What troubleshooting have you done? Do regular dynamic mics still work?
Have you tried other condenser mics to narrow it down to the phantom
power? Different channels on the mixer, etc...?

Nothing you did seems out of the ordinary. Generally, people turn
phantom power off when plugging/unplugging mics, but you shouldn't have to.

Cheers,
Trevor de Clercq


Mike Azzopardi wrote:
> Hi
>
> I have a MXL990 condenser mic and a Behringer UB1202 mixer.
> Everything was working fine with the phantom power.
> I then made plugged in my shure sm57 while I still had the phantom power on
> (MXL was unplugged at this point), and ever since, the phantom power doesn't
> seem to work (although the LED is on)
>
> Have I broken my mixers phantom power by plugging in another dynamic mic
> while the phantom power was on?
>
> I hope not :-)
>
> Thanks for any assistance.
>
> Mike
>
>
Anonymous
February 8, 2005 9:14:28 PM

Archived from groups: rec.audio.pro (More info?)

"Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
news:7k7Od.630$AC.368@newsfe2-gui.ntli.net
> Hi
>
> I have a MXL990 condenser mic and a Behringer UB1202 mixer.
> Everything was working fine with the phantom power.
> I then made plugged in my shure sm57 while I still had the phantom
> power on (MXL was unplugged at this point), and ever since, the
> phantom power doesn't seem to work (although the LED is on)

The world is full of people who like myself have used Behringer mixers with
a mixture of condenser and dynamic mics at the same time. No problem
expected, no problem found.

> Have I broken my mixers phantom power by plugging in another dynamic
> mic while the phantom power was on?

Probably just a coincidence.

Phantom power is applied to each mic through current-limiting resistors. The
voice coil in a dynamic mics is floating with respect to ground, so no
phantom current can flow, anyhow.

If you plugged a dead short to ground into a phantomed input, the resistors
would reduce the current flow below that which would harm the mixer.

Things are slightly different with respect to certain kinds of sources that
might be accidentally hooked to a phantomed input, such as a line level
output. The blocking capacitors in a phantom powered mic input can pick up a
charge from the phantom power supply. If an active circuit such as a line
output is applied to a phantomed input, currents sufficient to burn out
active components in the line output stage can flow briefly. The phantom
input itself will not be permanently damaged, but the line output stage can
be blown.
Related resources
February 8, 2005 9:14:28 PM

Archived from groups: rec.audio.pro (More info?)

You probably have a intermittant mic cable that NOW isn't passing
phantom power.

There is no resonable way that anything you did should "blow out" the
phantom power.

Mark
Anonymous
February 8, 2005 9:48:12 PM

Archived from groups: rec.audio.pro (More info?)

My dynamic mics work fine still. Both plugged into the MIC and Line Ins on
the mixer.
I'm taking the Condensor mic back to the shop tomorrow to test there, but
this mix is brand new.
The only other thing I remember doing was using a 1/4 cable to plug the
condensor mic in and then read that it has to be XLR.
I thought I'd try this group as I've heard that cheap behringer mixers have
lots of problems (my last one had a different problem)

Mike

"Trevor de Clercq" <declerct@IDONTLIKESPAMnewschool.edu> wrote in message
news:1107887424.45f5c8fae62c2263901d85c9002f29d6@teranews...
> What troubleshooting have you done? Do regular dynamic mics still work?
> Have you tried other condenser mics to narrow it down to the phantom
> power? Different channels on the mixer, etc...?
>
> Nothing you did seems out of the ordinary. Generally, people turn phantom
> power off when plugging/unplugging mics, but you shouldn't have to.
>
> Cheers,
> Trevor de Clercq
>
>
> Mike Azzopardi wrote:
>> Hi
>>
>> I have a MXL990 condenser mic and a Behringer UB1202 mixer.
>> Everything was working fine with the phantom power.
>> I then made plugged in my shure sm57 while I still had the phantom power
>> on (MXL was unplugged at this point), and ever since, the phantom power
>> doesn't seem to work (although the LED is on)
>>
>> Have I broken my mixers phantom power by plugging in another dynamic mic
>> while the phantom power was on?
>>
>> I hope not :-)
>>
>> Thanks for any assistance.
>>
>> Mike
>>
Anonymous
February 8, 2005 9:48:13 PM

Archived from groups: rec.audio.pro (More info?)

The phantom power doesn't go over the 1/4" connection, so that won't
work. But if you've tried it with an XLR-XLR and it still doesn't work,
then it's either the mic or the mixer (or something else you're doing
that I can't see).

I've never owned a Behringer mixer, but I tend to stay away from their
stuff. It's too inexpensive to be true. Plus I was a Mackie fan before
Behringer came out and copied their stuff, and loyalty dies hard with me
for some reason.

Cheers,
Trevor de Clercq


Mike Azzopardi wrote:
> My dynamic mics work fine still. Both plugged into the MIC and Line Ins on
> the mixer.
> I'm taking the Condensor mic back to the shop tomorrow to test there, but
> this mix is brand new.
> The only other thing I remember doing was using a 1/4 cable to plug the
> condensor mic in and then read that it has to be XLR.
> I thought I'd try this group as I've heard that cheap behringer mixers have
> lots of problems (my last one had a different problem)
>
> Mike
>
> "Trevor de Clercq" <declerct@IDONTLIKESPAMnewschool.edu> wrote in message
> news:1107887424.45f5c8fae62c2263901d85c9002f29d6@teranews...
>
>>What troubleshooting have you done? Do regular dynamic mics still work?
>>Have you tried other condenser mics to narrow it down to the phantom
>>power? Different channels on the mixer, etc...?
>>
>>Nothing you did seems out of the ordinary. Generally, people turn phantom
>>power off when plugging/unplugging mics, but you shouldn't have to.
>>
>>Cheers,
>>Trevor de Clercq
>>
>>
>>Mike Azzopardi wrote:
>>
>>>Hi
>>>
>>>I have a MXL990 condenser mic and a Behringer UB1202 mixer.
>>>Everything was working fine with the phantom power.
>>>I then made plugged in my shure sm57 while I still had the phantom power
>>>on (MXL was unplugged at this point), and ever since, the phantom power
>>>doesn't seem to work (although the LED is on)
>>>
>>>Have I broken my mixers phantom power by plugging in another dynamic mic
>>>while the phantom power was on?
>>>
>>>I hope not :-)
>>>
>>>Thanks for any assistance.
>>>
>>>Mike
>>>
>
>
Anonymous
February 8, 2005 10:01:14 PM

Archived from groups: rec.audio.pro (More info?)

Thanks Trevor, I'll try the mic in the shop and if it turns out to be the
mixer, i wont buy another cheap behringer product again.
Infact the Main Mix LEDs never worked from day one. I should have known
then...........

--
Check out my music!
http://www.bluemenagerie.co.uk

"Trevor de Clercq" <declerct@IDONTLIKESPAMnewschool.edu> wrote in message
news:1107889020.4516d87c8c84ca17d9b191fca1bd44e7@teranews...
> The phantom power doesn't go over the 1/4" connection, so that won't work.
> But if you've tried it with an XLR-XLR and it still doesn't work, then
> it's either the mic or the mixer (or something else you're doing that I
> can't see).
>
> I've never owned a Behringer mixer, but I tend to stay away from their
> stuff. It's too inexpensive to be true. Plus I was a Mackie fan before
> Behringer came out and copied their stuff, and loyalty dies hard with me
> for some reason.
>
> Cheers,
> Trevor de Clercq
>
>
> Mike Azzopardi wrote:
>> My dynamic mics work fine still. Both plugged into the MIC and Line Ins
>> on the mixer.
>> I'm taking the Condensor mic back to the shop tomorrow to test there, but
>> this mix is brand new.
>> The only other thing I remember doing was using a 1/4 cable to plug the
>> condensor mic in and then read that it has to be XLR.
>> I thought I'd try this group as I've heard that cheap behringer mixers
>> have lots of problems (my last one had a different problem)
>>
>> Mike
>>
>> "Trevor de Clercq" <declerct@IDONTLIKESPAMnewschool.edu> wrote in message
>> news:1107887424.45f5c8fae62c2263901d85c9002f29d6@teranews...
>>
>>>What troubleshooting have you done? Do regular dynamic mics still work?
>>>Have you tried other condenser mics to narrow it down to the phantom
>>>power? Different channels on the mixer, etc...?
>>>
>>>Nothing you did seems out of the ordinary. Generally, people turn
>>>phantom power off when plugging/unplugging mics, but you shouldn't have
>>>to.
>>>
>>>Cheers,
>>>Trevor de Clercq
>>>
>>>
>>>Mike Azzopardi wrote:
>>>
>>>>Hi
>>>>
>>>>I have a MXL990 condenser mic and a Behringer UB1202 mixer.
>>>>Everything was working fine with the phantom power.
>>>>I then made plugged in my shure sm57 while I still had the phantom power
>>>>on (MXL was unplugged at this point), and ever since, the phantom power
>>>>doesn't seem to work (although the LED is on)
>>>>
>>>>Have I broken my mixers phantom power by plugging in another dynamic mic
>>>>while the phantom power was on?
>>>>
>>>>I hope not :-)
>>>>
>>>>Thanks for any assistance.
>>>>
>>>>Mike
>>>>
>>
Anonymous
February 8, 2005 10:01:15 PM

Archived from groups: rec.audio.pro (More info?)

Well if the problem is that you had a bad mic cable blow out the
Behringer or something, then the problem is really the bad mic cable,
not the mixer. You really have to narrow down where the problem
is....It's better to blow a cheap mixer rather than an inexpensive one.

Although maybe the mixer is bad. If the mixer is really defective, then
I'd take it back. Did you say you bought it recently? I once bought a
"store-demo" Mackie and had to bring it back because various things
weren't working. Sometimes these things get dropped....

Cheers,
Trevor de Clercq

Mike Azzopardi wrote:
> Thanks Trevor, I'll try the mic in the shop and if it turns out to be the
> mixer, i wont buy another cheap behringer product again.
> Infact the Main Mix LEDs never worked from day one. I should have known
> then...........
>
Anonymous
February 8, 2005 10:01:15 PM

Archived from groups: rec.audio.pro (More info?)

In article <_%7Od.3409$OI2.1418@newsfe1-gui.ntli.net> mikeazzo22@hotmail.com writes:

> Thanks Trevor, I'll try the mic in the shop and if it turns out to be the
> mixer, i wont buy another cheap behringer product again.
> Infact the Main Mix LEDs never worked from day one. I should have known
> then...........

It sounds like you got a dud. You said it was new. Return it to the
store where you bought it and get another one.

But in answer to your worries, it's practically impossible to "blow" phantom
power by just connecting a microphone, even with a shorted cable. But the
cable must be properly wired. The voltage is between pins 1-2 and pins 1-3,
so pin 1 must be connected.

It is, however, possible to blow the microphone input stage by plugging or
unplugging a microphone cable with phantom power turned on unless the
circuit is properly protected. If this happened, that channel wouldn't work
with a dynamic mic either, so you probably didn't do that.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
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 here: double-m-eleven-double-zero at yahoo
Anonymous
February 8, 2005 10:05:31 PM

Archived from groups: rec.audio.pro (More info?)

Perhpas the Shure was on a bad mic cable. I am not sure but a mic cable
with pin 1 shorted to either pin 2 or pin 3 would short out the phantom.
Could this not kill some component in the phantom power supply?

You wouldn't know if the mic cable was bad since it would still work with
a dynamic this way, albeit with a lower output.

Rob R.

Mike Azzopardi <mikeazzo22@hotmail.com> wrote:
> My dynamic mics work fine still. Both plugged into the MIC and Line Ins on
> the mixer.
> I'm taking the Condensor mic back to the shop tomorrow to test there, but
> this mix is brand new.
> The only other thing I remember doing was using a 1/4 cable to plug the
> condensor mic in and then read that it has to be XLR.
> I thought I'd try this group as I've heard that cheap behringer mixers have
> lots of problems (my last one had a different problem)

> Mike

> "Trevor de Clercq" <declerct@IDONTLIKESPAMnewschool.edu> wrote in message
> news:1107887424.45f5c8fae62c2263901d85c9002f29d6@teranews...
>> What troubleshooting have you done? Do regular dynamic mics still work?
>> Have you tried other condenser mics to narrow it down to the phantom
>> power? Different channels on the mixer, etc...?
>>
>> Nothing you did seems out of the ordinary. Generally, people turn phantom
>> power off when plugging/unplugging mics, but you shouldn't have to.
>>
>> Cheers,
>> Trevor de Clercq
>>
>>
>> Mike Azzopardi wrote:
>>> Hi
>>>
>>> I have a MXL990 condenser mic and a Behringer UB1202 mixer.
>>> Everything was working fine with the phantom power.
>>> I then made plugged in my shure sm57 while I still had the phantom power
>>> on (MXL was unplugged at this point), and ever since, the phantom power
>>> doesn't seem to work (although the LED is on)
>>>
>>> Have I broken my mixers phantom power by plugging in another dynamic mic
>>> while the phantom power was on?
>>>
>>> I hope not :-)
>>>
>>> Thanks for any assistance.
>>>
>>> Mike
>>>
Anonymous
February 8, 2005 10:16:12 PM

Archived from groups: rec.audio.pro (More info?)

Hi Arny, thanks for the input. That all sounds a bit too technical to me.
When I thought the XLR mic cable might be at fault I unplugged it from the
mic, and unscrewed the end while still plugged into the mixer with phantom
power on. I touched the internals to check they looked wired correctly, and
remember they give a small buzz when doing so.
Could this have blown the phantom power?


"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:p a6dnZeJtILtkZTfRVn-tw@comcast.com...
> "Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
> news:7k7Od.630$AC.368@newsfe2-gui.ntli.net
>> Hi
>>
>> I have a MXL990 condenser mic and a Behringer UB1202 mixer.
>> Everything was working fine with the phantom power.
>> I then made plugged in my shure sm57 while I still had the phantom
>> power on (MXL was unplugged at this point), and ever since, the
>> phantom power doesn't seem to work (although the LED is on)
>
> The world is full of people who like myself have used Behringer mixers
> with a mixture of condenser and dynamic mics at the same time. No problem
> expected, no problem found.
>
>> Have I broken my mixers phantom power by plugging in another dynamic
>> mic while the phantom power was on?
>
> Probably just a coincidence.
>
> Phantom power is applied to each mic through current-limiting resistors.
> The voice coil in a dynamic mics is floating with respect to ground, so
> no phantom current can flow, anyhow.
>
> If you plugged a dead short to ground into a phantomed input, the
> resistors would reduce the current flow below that which would harm the
> mixer.
>
> Things are slightly different with respect to certain kinds of sources
> that might be accidentally hooked to a phantomed input, such as a line
> level output. The blocking capacitors in a phantom powered mic input can
> pick up a charge from the phantom power supply. If an active circuit such
> as a line output is applied to a phantomed input, currents sufficient to
> burn out active components in the line output stage can flow briefly. The
> phantom input itself will not be permanently damaged, but the line output
> stage can be blown.
>
>
Anonymous
February 8, 2005 10:16:13 PM

Archived from groups: rec.audio.pro (More info?)

"Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
news:0e8Od.998$nX.339@newsfe2-win.ntli.net

>When I thought the XLR mic cable might be at fault I unplugged it
> from the mic, and unscrewed the end while still plugged into the
> mixer with phantom power on. I touched the internals to check they
> looked wired correctly, and remember they give a small buzz when
> doing so. Could this have blown the phantom power?

A mic that's shorted is not supposed to be capable of blowing a console's
phantom power supply, regardless. Those current limiting resistors I
mentioned (usually about 5,600 ohms) limit the current from the phantom
supply to an amount that should be well within the limits of the mixer. The
mic input itself has current and voltage limiting features that protect it
from being harmed by most sources, as well.

People plug and unplug mics into phantomed inputs all the time without
taking any special precautions. The clicks and pops can be kinda ugly
sounding if monitors are on and sliders are up, but nothing need be harmed.

If a console couldn't withstand hot plugging or unplugging, then it would be
exposed to damage every time someone kicked a mic cable and unplugged a mic.

Think about a mic mixer being used for SR with about 20 mics attached.
Serveral times during setup someone is going to want to add or pull a mic.
No way is someone going to power the mixer down each time. I work with a SR
system that has a very effective limiter just before the power amp. The
clicks and pops can be loud and ugly, but they are unconditionally limited
to be on the safe side of speaker damage.

What might be expected to harm a mixer? Perhaps if you plugged a 120 volt
power line into a mic input, the mixer input might be harmed. This is not a
totally unlikely situation, as there can be bad grounding problems in the
real world. Perhaps some kind of major static discharge or near lightening
strike might take place.

Sometimes stuff is just going to fail at a particular time for its own
reasons, and you simply happen by chance to be doing something vaguely
related in the same approximate time period. Correlation does not prove
causuality.

I see this all the time with hard drives. Hard drives can fail sitting on
the shelf, even if hooked up. OK, lets say it is installed and the next time
someone powers the the PC up, you discover that hard drive failed. But you
really have no way of knowing whether it was what you did that triggered the
failure, or if that the drive was simply going to fail for its own reasons
at that particular point in time.
Anonymous
February 8, 2005 10:25:40 PM

Archived from groups: rec.audio.pro (More info?)

I dont know anything about cables, but i did look at the XLR cable, and it
had 2 and 3 wired. and 1 wasn't. I touched them, to see if the wiring was
correct while still plugged in. I dont know what the ends of my 1/4 cable
are like. But as mentioned before, I did try using this cable too and it
didn't work - Maybe one of these 2 things killed the phantom power?

both cables worked with the shure afterwards.

"Rob Reedijk" <reedijk@hera.med.utoronto.ca> wrote in message
news:cub2hr$9hs$1@news1.chem.utoronto.ca...
> Perhpas the Shure was on a bad mic cable. I am not sure but a mic cable
> with pin 1 shorted to either pin 2 or pin 3 would short out the phantom.
> Could this not kill some component in the phantom power supply?
>
> You wouldn't know if the mic cable was bad since it would still work with
> a dynamic this way, albeit with a lower output.
>
> Rob R.
>
> Mike Azzopardi <mikeazzo22@hotmail.com> wrote:
>> My dynamic mics work fine still. Both plugged into the MIC and Line Ins
>> on
>> the mixer.
>> I'm taking the Condensor mic back to the shop tomorrow to test there, but
>> this mix is brand new.
>> The only other thing I remember doing was using a 1/4 cable to plug the
>> condensor mic in and then read that it has to be XLR.
>> I thought I'd try this group as I've heard that cheap behringer mixers
>> have
>> lots of problems (my last one had a different problem)
>
>> Mike
>
>> "Trevor de Clercq" <declerct@IDONTLIKESPAMnewschool.edu> wrote in message
>> news:1107887424.45f5c8fae62c2263901d85c9002f29d6@teranews...
>>> What troubleshooting have you done? Do regular dynamic mics still work?
>>> Have you tried other condenser mics to narrow it down to the phantom
>>> power? Different channels on the mixer, etc...?
>>>
>>> Nothing you did seems out of the ordinary. Generally, people turn
>>> phantom
>>> power off when plugging/unplugging mics, but you shouldn't have to.
>>>
>>> Cheers,
>>> Trevor de Clercq
>>>
>>>
>>> Mike Azzopardi wrote:
>>>> Hi
>>>>
>>>> I have a MXL990 condenser mic and a Behringer UB1202 mixer.
>>>> Everything was working fine with the phantom power.
>>>> I then made plugged in my shure sm57 while I still had the phantom
>>>> power
>>>> on (MXL was unplugged at this point), and ever since, the phantom power
>>>> doesn't seem to work (although the LED is on)
>>>>
>>>> Have I broken my mixers phantom power by plugging in another dynamic
>>>> mic
>>>> while the phantom power was on?
>>>>
>>>> I hope not :-)
>>>>
>>>> Thanks for any assistance.
>>>>
>>>> Mike
>>>>
>
>
Anonymous
February 8, 2005 10:28:01 PM

Archived from groups: rec.audio.pro (More info?)

Rob Reedijk wrote:
> Perhpas the Shure was on a bad mic cable. I am not sure but a mic cable
> with pin 1 shorted to either pin 2 or pin 3 would short out the phantom.
> Could this not kill some component in the phantom power supply?
>
No, it comes though a 6.8k resistor and couldn't draw enough current to
do any damage, but a cable like that is very likely to prevent a mic
from working with it if that mic needs phantom power - it'll be getting
power on only one leg instead of both, half volts at best!

--
Anahata
anahata@treewind.co.uk -+- http://www.treewind.co.uk
Home: 01638 720444 Mob: 07976 263827
Anonymous
February 8, 2005 10:35:49 PM

Archived from groups: rec.audio.pro (More info?)

Mike Azzopardi wrote:
> I dont know anything about cables, but i did look at the XLR cable, and it
> had 2 and 3 wired. and 1 wasn't.

If that's the one you were using with the phantom powered mic, there's
your answer. For phantom power to work, all three have to be wired. Pin
1 is the cable screen (shield) but also a conductor for the phantom
power and must be connected through.

--
Anahata
anahata@treewind.co.uk -+- http://www.treewind.co.uk
Home: 01638 720444 Mob: 07976 263827
Anonymous
February 8, 2005 10:42:18 PM

Archived from groups: rec.audio.pro (More info?)

So maybe my mic was working with this bad XLR lead (it was £4 off ebay after
all!), but was only on half power as it were? and then it eventually died. I
dont have another XLR lead here to test right now.
I'll go to the shop tomorrow, try it all out there and determine which
componant is faulty and then post a reply. Hopefully it was just the lead
and it hasn't done the mixer any lasting damage

Thanks to everyone for the advice.

--
Check out my music!
http://www.bluemenagerie.co.uk

"anahata" <anahata@reply-to.address> wrote in message
news:420912c1$0$22497$ed2619ec@ptn-nntp-reader03.plus.net...
> Rob Reedijk wrote:
>> Perhpas the Shure was on a bad mic cable. I am not sure but a mic cable
>> with pin 1 shorted to either pin 2 or pin 3 would short out the phantom.
>> Could this not kill some component in the phantom power supply?
>>
> No, it comes though a 6.8k resistor and couldn't draw enough current to do
> any damage, but a cable like that is very likely to prevent a mic from
> working with it if that mic needs phantom power - it'll be getting power
> on only one leg instead of both, half volts at best!
>
> --
> Anahata
> anahata@treewind.co.uk -+- http://www.treewind.co.uk
> Home: 01638 720444 Mob: 07976 263827
Anonymous
February 8, 2005 11:04:04 PM

Archived from groups: rec.audio.pro (More info?)

ok great. so hopefully this is it.
This newsgroup is so cool.

- How did it work for a while then if pin 1 wasn't wired?
- When I buy another XLR cable, how do I know if it has all the pins wired?


Thanks again

--
Check out my music!
http://www.bluemenagerie.co.uk

"anahata" <anahata@reply-to.address> wrote in message
news:42091495$0$70396$ed2619ec@ptn-nntp-reader03.plus.net...
> Mike Azzopardi wrote:
>> I dont know anything about cables, but i did look at the XLR cable, and
>> it had 2 and 3 wired. and 1 wasn't.
>
> If that's the one you were using with the phantom powered mic, there's
> your answer. For phantom power to work, all three have to be wired. Pin 1
> is the cable screen (shield) but also a conductor for the phantom power
> and must be connected through.
>
> --
> Anahata
> anahata@treewind.co.uk -+- http://www.treewind.co.uk
> Home: 01638 720444 Mob: 07976 263827
Anonymous
February 9, 2005 12:13:25 PM

Archived from groups: rec.audio.pro (More info?)

Jim Gregory wrote:
> "Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
> news:7k7Od.630$AC.368@newsfe2-gui.ntli.net...
>
> Mike (a very appropriate name)
> Here's my offering.....
>
>
> So-called 48V phantom voltage (not T powering) for mics can lie
between 30V
> (usually Shure) and 50V DC.
> It delivers very low current (never more than 1.5mA, being the sum of
both
> legs, into a suitable capacitor or condenser mic's back-end) and ONLY
when
> that mic is connected (you should avoid lo-Z dynamic ones and do
prohibit
> lo-Z ribbons!)
> The two 6k8 resistors from the regulated + supply, each one in series
with
> XLR pin 2 and with pin 3, will current-limit the device.They are
supposed to
> be matched to better than 0.5% of one another, so that there is
hardly any
> DC present across a dynamic's coil. The 0V is supplied via the cable
screen
> to pin 1.
> The phantom current is delivered to the centre tap of the capacitor
mic
> interface and its return on pin 1, and is not hostile to AF. It is
> DIFFICULTT
> to damage the supply, easier to clobber the mic. Always check your
own
> wiring and of anything
> borrowed or hired for standards compatibility
> You can use Phantom on 3-pole 1/4" A plugs, if the mixer or stage box
is
> furnished with these, and same principles apply.
>
> When measuring a suspect mic or a mic via a lead, any DC current
pulsed
> across it from an analogue test meter can magnetise it, or worse
still, if
> checking the cable run and it is accidentally still connected, the
> associated mic transformer of the host device. Sometimes these i/p
trannies
> have to be degaussed properly to remove noise. But don't ask me how
it's
> done!
>
> Jim Gregory


Using jacks on a phantom circuit is a bad idea because plugging in may
put the phantom power across the hot and cold connections to the mic
for a moment.
Not good for any mic and could even blow your monitors.

Steve Lane
Anonymous
February 9, 2005 4:45:45 PM

Archived from groups: rec.audio.pro (More info?)

Mike Azzopardi wrote:
> Hopefully it was just the lead
> and it hasn't done the mixer any lasting damage

Just to summarize some of what's been said about that: short of
something really daft like connecting the AC power to it, NOTHING you
can do with a mic cable (like shorting any pin to any other) should do
any permanent damage to a mixer. If your mixer is cabaple of getting
damaged just by that, it's so badly designed/made you should trash it
and get a better one.

(if it's Behringer, that's not outside the bounds of possibility...)

Anahata
Anonymous
February 9, 2005 7:34:46 PM

Archived from groups: rec.audio.pro (More info?)

"Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
news:7k7Od.630$AC.368@newsfe2-gui.ntli.net...

Mike (a very appropriate name)
Here's my offering.....


So-called 48V phantom voltage (not T powering) for mics can lie between 30V
(usually Shure) and 50V DC.
It delivers very low current (never more than 1.5mA, being the sum of both
legs, into a suitable capacitor or condenser mic's back-end) and ONLY when
that mic is connected (you should avoid lo-Z dynamic ones and do prohibit
lo-Z ribbons!)
The two 6k8 resistors from the regulated + supply, each one in series with
XLR pin 2 and with pin 3, will current-limit the device.They are supposed to
be matched to better than 0.5% of one another, so that there is hardly any
DC present across a dynamic's coil. The 0V is supplied via the cable screen
to pin 1.
The phantom current is delivered to the centre tap of the capacitor mic
interface and its return on pin 1, and is not hostile to AF. It is
DIFFICULTT
to damage the supply, easier to clobber the mic. Always check your own
wiring and of anything
borrowed or hired for standards compatibility
You can use Phantom on 3-pole 1/4" A plugs, if the mixer or stage box is
furnished with these, and same principles apply.

When measuring a suspect mic or a mic via a lead, any DC current pulsed
across it from an analogue test meter can magnetise it, or worse still, if
checking the cable run and it is accidentally still connected, the
associated mic transformer of the host device. Sometimes these i/p trannies
have to be degaussed properly to remove noise. But don't ask me how it's
done!

Jim Gregory
Anonymous
February 9, 2005 7:49:05 PM

Archived from groups: rec.audio.pro (More info?)

Hi all

Thanks for EVERYONEs replies in helping me with this. I just got back from
the shop, and it turned out to be my lead. Got a new balanced XLR and its
fine now. I still dont understand how it worked for a little while using the
old faulty lead, but I guess thats leads for you. Opening it up was never
gonna be a good thing, but you live and you learn. Thanks to you guys I know
about half a dozen things I didn't know before from this thread, so thank
you all and happy recording!

Best Regards
Mike


--
Check out my music!
http://www.bluemenagerie.co.uk

"Jim Gregory" <jim.greg@ntlworld.com> wrote in message
news:GYqOd.4811$Z%2.2066@newsfe3-gui.ntli.net...
>
> "Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
> news:7k7Od.630$AC.368@newsfe2-gui.ntli.net...
>
> Mike (a very appropriate name)
> Here's my offering.....
>
>
> So-called 48V phantom voltage (not T powering) for mics can lie between
> 30V
> (usually Shure) and 50V DC.
> It delivers very low current (never more than 1.5mA, being the sum of both
> legs, into a suitable capacitor or condenser mic's back-end) and ONLY when
> that mic is connected (you should avoid lo-Z dynamic ones and do prohibit
> lo-Z ribbons!)
> The two 6k8 resistors from the regulated + supply, each one in series with
> XLR pin 2 and with pin 3, will current-limit the device.They are supposed
> to
> be matched to better than 0.5% of one another, so that there is hardly any
> DC present across a dynamic's coil. The 0V is supplied via the cable
> screen
> to pin 1.
> The phantom current is delivered to the centre tap of the capacitor mic
> interface and its return on pin 1, and is not hostile to AF. It is
> DIFFICULTT
> to damage the supply, easier to clobber the mic. Always check your own
> wiring and of anything
> borrowed or hired for standards compatibility
> You can use Phantom on 3-pole 1/4" A plugs, if the mixer or stage box is
> furnished with these, and same principles apply.
>
> When measuring a suspect mic or a mic via a lead, any DC current pulsed
> across it from an analogue test meter can magnetise it, or worse still, if
> checking the cable run and it is accidentally still connected, the
> associated mic transformer of the host device. Sometimes these i/p
> trannies
> have to be degaussed properly to remove noise. But don't ask me how it's
> done!
>
> Jim Gregory
>
Anonymous
February 9, 2005 7:49:06 PM

Archived from groups: rec.audio.pro (More info?)

Mike Azzopardi wrote:

> Hi all
>
> Thanks for EVERYONEs replies in helping me with this. I just got back from
> the shop, and it turned out to be my lead. Got a new balanced XLR and its
> fine now. I still dont understand how it worked for a little while using the
> old faulty lead, but I guess thats leads for you. Opening it up was never
> gonna be a good thing, but you live and you learn. Thanks to you guys I know
> about half a dozen things I didn't know before from this thread, so thank
> you all and happy recording!

Opening up an XLR should never be that big a deal, as long as you
remember that there are fragile things under the cover and some care
needs to be taken. Don't be skittish about taking them apart if you
need to; next time, though, loosen the strain relief before sliding the
housing back.
Anonymous
February 9, 2005 9:01:43 PM

Archived from groups: rec.audio.pro (More info?)

<sstevelp@aol.com> wrote in message
news:1107969205.410448.82480@o13g2000cwo.googlegroups.com...
>
> Jim Gregory wrote:
>> "Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
>> news:7k7Od.630$AC.368@newsfe2-gui.ntli.net...
>>
>> Mike (a very appropriate name)
>> Here's my offering.....
>>
>>
>> So-called 48V phantom voltage (not T powering) for mics can lie
> between 30V
>> (usually Shure) and 50V DC.
>> It delivers very low current (never more than 1.5mA, being the sum of
> both
>> legs, into a suitable capacitor or condenser mic's back-end) and ONLY
> when
>> that mic is connected (you should avoid lo-Z dynamic ones and do
> prohibit
>> lo-Z ribbons!)
>> The two 6k8 resistors from the regulated + supply, each one in series
> with
>> XLR pin 2 and with pin 3, will current-limit the device.They are
> supposed to
>> be matched to better than 0.5% of one another, so that there is
> hardly any
>> DC present across a dynamic's coil. The 0V is supplied via the cable
> screen
>> to pin 1.
>> The phantom current is delivered to the centre tap of the capacitor
> mic
>> interface and its return on pin 1, and is not hostile to AF. It is
>> DIFFICULTT
>> to damage the supply, easier to clobber the mic. Always check your
> own
>> wiring and of anything
>> borrowed or hired for standards compatibility
>> You can use Phantom on 3-pole 1/4" A plugs, if the mixer or stage box
> is
>> furnished with these, and same principles apply.
>>
>> When measuring a suspect mic or a mic via a lead, any DC current
> pulsed
>> across it from an analogue test meter can magnetise it, or worse
> still, if
>> checking the cable run and it is accidentally still connected, the
>> associated mic transformer of the host device. Sometimes these i/p
> trannies
>> have to be degaussed properly to remove noise. But don't ask me how
> it's
>> done!
>>
>> Jim Gregory
>
>
> Using jacks on a phantom circuit is a bad idea because plugging in may
> put the phantom power across the hot and cold connections to the mic
> for a moment.
> Not good for any mic and could even blow your monitors.
>
> Steve Lane
>

If having to use 3-pole jacks in lieu of XLRs, DINs, or whatever for powered
mic interfaces:....
Obviously you turn down your monitors or close associated faders, switch off
the Phantom to the relevant jack-furnished channels beforehand and switch it
back on after connecting! Then PFL the mics in turn. Don't forget the
distribution 6k8 resistors current-limit the medium voltage.
Jim
Anonymous
February 9, 2005 9:59:53 PM

Archived from groups: rec.audio.pro (More info?)

"Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
news:Um8Od.1003$nX.320@newsfe2-win.ntli.net...
>I dont know anything about cables, but i did look at the XLR cable, and it
>had 2 and 3 wired. and 1 wasn't. I touched them, to see if the wiring was
>correct while still plugged in. I dont know what the ends of my 1/4 cable
>are like.

So where did you plug the 1/4" plug into ? No phantom power should come out
a 1/4" Line In jack....


geoff
Anonymous
February 9, 2005 10:02:55 PM

Archived from groups: rec.audio.pro (More info?)

"Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
news:0e8Od.998$nX.339@newsfe2-win.ntli.net...
> Hi Arny, thanks for the input. That all sounds a bit too technical to me.
> When I thought the XLR mic cable might be at fault I unplugged it from the
> mic, and unscrewed the end while still plugged into the mixer with phantom
> power on. I touched the internals to check they looked wired correctly,
> and remember they give a small buzz when doing so.
> Could this have blown the phantom power?

No, but as you evidently have zero knowledge about cables, wires, and
phantom power, what made you think opening the cable was a good idea.

I suggest that in doing so you have broken at least one of the signal wires
or screen.

geoff
Anonymous
February 9, 2005 10:02:56 PM

Archived from groups: rec.audio.pro (More info?)

Geoff Wood wrote:

> "Mike Azzopardi" <mikeazzo22@hotmail.com> wrote in message
> news:0e8Od.998$nX.339@newsfe2-win.ntli.net...
>
>>Hi Arny, thanks for the input. That all sounds a bit too technical to me.
>>When I thought the XLR mic cable might be at fault I unplugged it from the
>>mic, and unscrewed the end while still plugged into the mixer with phantom
>>power on. I touched the internals to check they looked wired correctly,
>>and remember they give a small buzz when doing so.
>>Could this have blown the phantom power?
>
>
> No, but as you evidently have zero knowledge about cables, wires, and
> phantom power, what made you think opening the cable was a good idea.
>
> I suggest that in doing so you have broken at least one of the signal wires
> or screen.
>

That's about the only way the condensor could have worked and then not.
Anonymous
February 10, 2005 12:27:12 AM

Archived from groups: rec.audio.pro (More info?)

On Tue, 08 Feb 2005 19:16:12 GMT, "Mike Azzopardi"
<mikeazzo22@hotmail.com> wrote:

>Hi Arny, thanks for the input. That all sounds a bit too technical to me.
>When I thought the XLR mic cable might be at fault I unplugged it from the
>mic, and unscrewed the end while still plugged into the mixer with phantom
>power on. I touched the internals to check they looked wired correctly, and
>remember they give a small buzz when doing so.
>Could this have blown the phantom power?

None of the things you have done should have "blown" the phantom
power.

But you keep releasing tit-bits of information. First you just tell
us you connected a SM57. Then, a few messages later, you mention a
1/4" jack. Now this finger business.

Why not tell us EVERYTHING you did, right now? Save us having to
drag it out of you. :-)

CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm
"Possibly the world's least impressive web site": George Perfect
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