dynamic capsule help

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OneRoomStudios

OneRoomStudios

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So par Doc's advice, I am in the process of building my first mic - a dynamic harp mic that he gave me the link for. I have most of the mic done but I have run into one small confusion: the capsule has no leads on it, only two contacts on the underside. One contact has a black dot on it an there are no other markings. Does anyone know or want to venture a guess as to which one is + and - ? Thanks,

-Peter
 
OneRoomStudios said:
So par Doc's advice, I am in the process of building my first mic - a dynamic harp mic that he gave me the link for. I have most of the mic done but I have run into one small confusion: the capsule has no leads on it, only two contacts on the underside. One contact has a black dot on it an there are no other markings. Does anyone know or want to venture a guess as to which one is + and - ? Thanks,

-Peter
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I don't know, but many times with electrical... red is + and black is -.
 
My guess, if only one contact has any kind of marking and the other has none, the one with the mark is the hot (+) out and the other is return.
 
Its dynamic. Someone please correct me if im wrong, but does it matter which is which? cos its not being phantom powered or anything so it would just maybe change the phase?

-david-
 
I've always wondered how a dynamic mic can ignore phantom power when it's present, maybe that's why this wiring question is important.
 
Phyl:

Most dynamic mics can easily ignore phantom because they use a transformer. Phantom power is DC(direct current), all audio signals and mains power is AC(alternating current). Transformers only work with AC, not DC. therefore, the mic simply ignores the phantom power.

As for dynamic mics without a transformer, i'm less sure. I imagine that the current simply passes through the capsule.
 
Ok, so how does this sound: contact with the black dot goes through the potentiometer and to the tip of the phone socket, and the plain contact goes through the potentiometer and to the sleve of the phone socket? That assumes that the dot contact is + and should work right? If I'm mistaken please set me straight, thanks.

-Peter
 
davide said:
Its dynamic. Someone please correct me if im wrong, but does it matter which is which? cos its not being phantom powered or anything so it would just maybe change the phase?

-david-
Click to expand...
I think you might be right. I think the thing that will matter is if you use the mic with other mics. The mic will work no matter which way it is wired, but if it is backwards it will be out of phase with other mics.

The standard is that positive pressure on the diaphragm creates a positive voltage on pin 2 of an XLR (+), which is the tip or hot on a TS 1/4" cable.

I don't know an easy way to check except wire it up and put it next to another mic in front of a sound source(like an amp) and listen to both of the mics one at a time and together on headphones or monitors. If the sound gets thin, or drops a lot in volume when you listen to both of them together the mic is out of phase.

But it sound like the black dot is + to me.
 
OneRoomStudios said:
Ok, so how does this sound: contact with the black dot goes through the potentiometer and to the tip of the phone socket, and the plain contact goes through the potentiometer and to the sleve of the phone socket? That assumes that the dot contact is + and should work right? If I'm mistaken please set me straight, thanks.

-Peter
Click to expand...
Yes, "if" the black dot is + it would connect to the tip of the phone socket.
 
Peter,

It is hard to say which is which. The way you connect it will affect phase only. You could easily figure it out if you have another mic with known right phase--it can be even condenser. Randomly connect one of the contacts of your capsule to pin 2 and another to pin 3 of XLR, and ground pin 1. Adjust gains of both mics for approx. same volume, and pan both into center. Put them as close as it is possible to each other and try to talk in bass range into both of them. Then move one of them away. If you hear that amount of LF is the same, then your mic has the same phase as another. If you feel that with one mic you hear more bass than with two, then swap connectors of your mic between pins 2 and 3 on XLR.

And one more thing--please no pots between your mic and pre. You will screw up impedance matching and also, noise will go up.

Hope it helps.
 
Sorry Boingoman,

Just read all the post and saw that you have already posted about it.
 
Marik said:
Peter,

It is hard to say which is which. The way you connect it will affect phase only. You could easily figure it out if you have another mic with known right phase--it can be even condenser. Randomly connect one of the contacts of your capsule to pin 2 and another to pin 3 of XLR, and ground pin 1. Adjust gains of both mics for approx. same volume, and pan both into center. Put them as close as it is possible to each other and try to talk in bass range into both of them. Then move one of them away. If you hear that amount of LF is the same, then your mic has the same phase as another. If you feel that with one mic you hear more bass than with two, then swap connectors of your mic between pins 2 and 3 on XLR.

And one more thing--please no pots between your mic and pre. You will screw up impedance matching and also, noise will go up.

Hope it helps.
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Very good advice, as usual, but not for this project.

First of all, it's for harmonica, so the level control is needed, and it also means that the mic will probably be used unbalanced into a Hi-Z guitar amp input.
 
Harvey Gerst said:
First of all, it's for harmonica, so the level control is needed, and it also means that the mic will probably be used unbalanced into a Hi-Z guitar amp input.
Click to expand...

Oops! My bad.
 
Thanks for the help guys. I finished the mic and it works! In case any of you were curious, the black dot was +. I'm going to attach some pics. It gives new meaning to "baby bottle microphone." Thanks again for the help!
 

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COOL! Glad it works. Tho I gotta say it looks like something I used to suck through, not blow into. :D :D :D :D
 
So you built a mic that doubles as a bong. :D Fucking GENIUS!!
 
Great job on the mic - sorry I missed this thread yesterday.
How do you hold it to play harp into it - it looks a little cumbersome? Doesn't the water tend to slosh around a lot when you play? :)
 
Now that i think about it, the mic does resemble a "tobacco water pipe," but then again, I think it's just because the scale is hard to guage from the pics. The whole thing is only about 6" tall, and the bulb where the pot is (that's potentiometer, not mary jane) fits perfectly in cupped hands while playing harp. If I was actually decent at plaing harmonica, I would record a sample for you guys, but I suck...so maybe once I can find a real harp player to try it out I'll record a little something. Now for the next project...a SM57 clone (sort of).
 
OneRoomStudios said:
. Now for the next project...a SM57 clone (sort of).
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Be sure to check out the thread about 57/58 freq. response. Lots of helpful info there :D .
 
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