Phantom Power on Dynamic Mics
mcp6453
converter. The Icicle has phantom power that cannot be disabled. Normally I hook
the converter to my Heil PR40 before I plug in the USB, and everything works
extremely well. When I connected the D1000E, I did so with the phantom on. As
soon as I made the connection, I heard a clear pop come out of the element. Oh,
well. There goes the mic.
When I hooked the mic to a Shure X2U with no phantom to make sure it was blown,
the mic worked and sounded like normal. Then I connected the D1000E back to the
Icicle and connected the USB plug as I should have done. There was another pop,
and the mic did not work.
The mic still works, so I guess I'm lucky (unless there is latent damage that
ultimately manifests itself.) Does this scenario suggest that there is a wiring
problem in the D1000E, such as pin 2 or pin 3 shorted to ground? It's an easy
check, but I ask the question in case there is something else funky going on
with the D1000E.
As an aside, the D1000E is a much better sounding vocal mic than the SM58 (which
works fine on the Icicle). It's surprising how different they are.
Sean Conolly
news:fuqdncp_4vER2aTT...@giganews.com...
The pops are typical when phantom power is plugged in OR turned on, since
most circuits don't ramp up the phantom power gradually. This is one feature
that I really like on my RNP: it ramps up the 48v slowly enough to not
damage anything or send a pop through the PA in a live situation.
If you can't disable the phantom power the you should probably reserve that
converter for condenser mics only. I can't say why it doesn't work with that
particular mic, may be the mic has a low enough DC resistance to draw more
current than the converter likes.
Sean
alex
no damage because the coil of dyn mics is usually protected against DC
by a transformer. Are you sure you are using a balanced cable?
Unbalanced cables will shorten the phantom supply and the converter can
have trouble.
alex
Mike Rivers
> When I hooked the mic to a Shure X2U with no phantom to make sure it was blown,
> the mic worked and sounded like normal. Then I connected the D1000E back to the
> Icicle and connected the USB plug as I should have done. There was another pop,
> and the mic did not work.
>
> The mic still works, so I guess I'm lucky (unless there is latent damage that
> ultimately manifests itself.) Does this scenario suggest that there is a wiring
> problem in the D1000E, such as pin 2 or pin 3 shorted to ground?
That could definitely be a wiring problem.
--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson
http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff
mcp6453
> On 8/3/2011 8:52 AM, mcp6453 wrote:
>
>> When I hooked the mic to a Shure X2U with no phantom to make sure it was blown,
>> the mic worked and sounded like normal. Then I connected the D1000E back to the
>> Icicle and connected the USB plug as I should have done. There was another pop,
>> and the mic did not work.
>>
>> The mic still works, so I guess I'm lucky (unless there is latent damage that
>> ultimately manifests itself.) Does this scenario suggest that there is a wiring
>> problem in the D1000E, such as pin 2 or pin 3 shorted to ground?
>
> That could definitely be a wiring problem.
>
Yep. Pin 2 was shorted to Pin 1. It looked like it was wired from the factory,
but it's hard to tell. It's now wired correctly with Pin 1 actually being a
short jumper soldered from Pin 1 to the case. That seems like a strange way to
make the connection to the case, but the solder seems to be sticking.
When I took the windscreen off, the foam material disintegrated. What kind of
foam can I use to create a new one? It's not essential, but it would be nice to
put it back. The rubber holding the capsule in place is in surprisingly good
condition, but it was hard to get the windscreen back on. Hopefully I can find
an exploded view of the D1000E somewhere to make sure everything is back to
normal. It's surprising how repairable this mic is.
As it sits now, the mic work well.
alex
> Yep. Pin 2 was shorted to Pin 1. It looked like it was wired from the factory,
> but it's hard to tell. It's now wired correctly with Pin 1 actually being a
> short jumper soldered from Pin 1 to the case. That seems like a strange way to
> make the connection to the case, but the solder seems to be sticking.
>
> When I took the windscreen off, the foam material disintegrated. What kind of
> foam can I use to create a new one? It's not essential, but it would be nice to
> put it back. The rubber holding the capsule in place is in surprisingly good
> condition, but it was hard to get the windscreen back on. Hopefully I can find
> an exploded view of the D1000E somewhere to make sure everything is back to
> normal. It's surprising how repairable this mic is.
>
> As it sits now, the mic work well.
this is what i was able to find. foam help to reduce explosive "p". you
can easy build one with any thin foam, or use an external pop/wind
filter. This only in the case you are going to use it outdoor or as
vocal microphone.
http://www.akg.com/mediendatenbank2/psfile/datei/2/D_10004055d3b12b2c7.zip
alex
Don Pearce
Somebody had wired the mic for unbalanced operation - probably to plug
it into a guitar amp. A normally wired mic will produce no sound when
plugged in that way because one end of the capsule is disconnected.
With the mis-wiring, the sound from the element when you plugged it
into the phantom input was inevitable, but I guess you have got lucky
and not damaged it.
A properly wired, balanced mic will make no sound when it is plugged
into a phantom-powered input as both ends of the capsule are always at
the same voltage - albeit a rather high 48V.
Your removing the pin1 to pin 2 short will have cured the problem.
With a bit of luck, you now have a properly working microphone.
d
Sean Conolly
news:4e3aed37...@news.eternal-september.org...
> A properly wired, balanced mic will make no sound when it is plugged
> into a phantom-powered input as both ends of the capsule are always at
> the same voltage - albeit a rather high 48V.
A properly wired & balanced *dynamic* mic won't pop, to be clear. Plugging
in a condensor mic hot will always pop in my experience. Same for turning on
the 48v on the board in most cases, if the mic is plugged in first you still
get a sizable pop, which is again one of the reasons I prefer to use my RNP
when I'm working with a house sound system.
Sean
Don Pearce
That's for an entirely different reason. When you plug in a condenser
you are starting up the electronics. There is a coupling cap to
charge,and that is the pop you hear.
A decently designed board will have a large electrolytic cap on the
48V line that will cause it to rise slowly, preventing a noticeable
pop.
d
alex
> A properly wired& balanced*dynamic* mic won't pop, to be clear. Plugging
> in a condensor mic hot will always pop in my experience. Same for turning on
> the 48v on the board in most cases, if the mic is plugged in first you still
> get a sizable pop, which is again one of the reasons I prefer to use my RNP
> when I'm working with a house sound system.
>
> Sean
when you plug a dynamic into a "phantomed" input you may experience a
loud pop too. this is because the pin 2 and 3 doesn't always close the
circuit at the same time during the plugging action.
Don Pearce
That makes no difference. Whichever pin touches last, it still has the
same voltage is the opposite pin, so there will be no pop.
d
alex
> That makes no difference. Whichever pin touches last, it still has the
> same voltage is the opposite pin, so there will be no pop.
same voltage ok, but i always get a noise! More a pulse than a pop, but
i get a sound when the phantom is in. i think this is due to the fact
that even a DC current, at the time of switching on (or plugging),
produces a very short electromagnetic field in the cable, which can
return to the preamplifier in form of pulse noise if not perfectly equal
on pin 2 and 3.
When you plug, the pins touches at slightly different time, so in this
short interval, the cable is not yet balanced and thus more sensible to EMI.
this is the only answer i can find :-)
mcp6453
It doesn't matter that the pins touch at different times. There is an open
circuit until BOTH pins touch.
Scott Dorsey
>
>It doesn't matter that the pins touch at different times. There is an open
>circuit until BOTH pins touch.
Right. The thump is just the electronics in the mike charging up and
coming up to voltage.
For the Josephson 606, there's so much filtration in the supply lines it
takes a good minute for that thump to finish up and everything to stabilize.
Schoeps Collette is almost as bad.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
alex
> It doesn't matter that the pins touch at different times. There is an open
> circuit until BOTH pins touch.
(sm58) too (only with phantom on) and the cable is OK, so i was trying
to figure out why...
I noticed that when i plug the mike for the first time the bump is loud
then the other times the bump is a lot less udible.
????
alex
Scott Dorsey
The DC blocking capacitors that keep the phantom power out of your preamp
input stage are charging up. You hear the thump because they don't charge
up at the same rate (since they are electrolytics that don't match well).
You'll hear the same thing if there's no mike plugged in at all.