Made a mic

  • Thread starter Thread starter rory
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Thats awesome, let us know how it goes! As far as using them as overheads, I've got a session scheduled this Sunday with a solo acoustic act. I believe we were going to be adding some backing tracks as well and if we do, I'll be sure to get some clips of the mic as an overhead.

Thanks,
Rory
 
Yeah you need to drop the voltage. Here's a circuit, if you scroll pretty far down to "balanced electret microphone circuit"

http://www.epanorama.net/circuits/microphone_powering.html

That holds the voltage into the capsule at about 8V (as always, subject to my math errors :o ), if you want 3V, change the zener to 4.3V.

One thing about that circuit, I dunno how you are supposed to fit 10uF film caps in a little mic. Those would probably have to be electros bypassed with 1uF poly film boxes if you like. I would take the same approach with the filter caps, no need to bother with different caps there.
 
The 10uF Caps are Pretty Small, they are about 3/4cm Tall, I"m useing Metal 10uF caps (I think aluminum) and they seem to work Fine.....

As for the Holders for the Watch Batteries what I did was Take a small Piece of plastic tubeing the same diameter as the Batteries and put a Plastic cap over each end that had the electrode stuck in the Middle of it ..
that way the each electrode picks up the charge from each end of the Battery.....

This is the Wireing that I use that deleivers a Ballanced Signal Via XLR...


Cheers
 

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Minion said:
The 10uF Caps are Pretty Small, they are about 3/4cm Tall, I"m useing Metal 10uF caps (I think aluminum) and they seem to work Fine.....
Click to expand...

Aluminum is electrolytic. Does it look like the one in rory's pic?

Mylar is metallized poly film, the smallest one I can find in 10uF is just a little smaller than a 9V battery. In an external power supply, like the mic you built, that fits fine. Electros will absolutely work too, it's just that polys are commonly thought to have better audio response.

Anyway, I was referring to the schemo I linked, which is driven by phantom power. That cap is too big to fit in a small omni mic body, especially if using an XLR connector for the body! So I think electro is the only possible choice there.

I just might try to bang together a phantom powered model . . .
 
mshilarious said:
Aluminum is electrolytic. Does it look like the one in rory's pic?

Mylar is metallized poly film, the smallest one I can find in 10uF is just a little smaller than a 9V battery. In an external power supply, like the mic you built, that fits fine. Electros will absolutely work too, it's just that polys are commonly thought to have better audio response.

Anyway, I was referring to the schemo I linked, which is driven by phantom power. That cap is too big to fit in a small omni mic body, especially if using an XLR connector for the body! So I think electro is the only possible choice there.

I just might try to bang together a phantom powered model . . .
Click to expand...

You could also use a mica or tantalium. The only problem is that electrolytic, mica and tantalium are all inferior for audio. I think I used tants in my tape op mics and they're not tooooo bad. You'd be better off with a good large body and using mylar or film.
 
PhilGood said:
No, wait a minute! I remember that the 1000pF goes into the mic body, but the 10uF mylar sits in the power box, which is connected via an XLR cable to the mic. Unless you want to have them all in the same housing.
Click to expand...

*sigh*

Yes, that works for the tape op mic. I am talking about a mod to use phantom power. Then the caps (plural, there must be at least two of them, if you don't use power supply filter caps) have to fit in the mic housing. Ain't much room inside an XLR connector, about 15mm L x 12mm D, and that would include the necessary resistors.

While it's true polys are superior, the reality of using a mic that is made from $10 in parts is that it's probably going into a preamp that has electros and plenty of 'em, and they probably aren't bypassed with small polys, etc.

I've got my schemo and parts list ready for the phantom version, I'll report back when I'm done. By necessity, I will have to use axial electros, and I don't have room for poly bypass caps.

I'll see what I get.
 
Hi, I was wondering if you of you guys could help me with a small problem I am haveing wireing up a Mic....

The problem is my Schematic doesn"t tell me which is the Negitive and the Positive lead when wireing the the 10uf Capacitor as electrolytics are Polarized and must be wired one way.....

I"m pretty new to wireing and electronix so I am still learning ....

I was thinking that since the Cap is comeing off of the Negitive lead from the Battery that i would put the negitive lead of the Cap on the left closest to the Negitive current from the battery but I don"t know if my reasoning is correct....

Can someone help me with this ??

ThanX
 

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mshilarious said:
*sigh*

Yes, that works for the tape op mic. I am talking about a mod to use phantom power. Then the caps (plural, there must be at least two of them, if you don't use power supply filter caps) have to fit in the mic housing. Ain't much room inside an XLR connector, about 15mm L x 12mm D, and that would include the necessary resistors.

While it's true polys are superior, the reality of using a mic that is made from $10 in parts is that it's probably going into a preamp that has electros and plenty of 'em, and they probably aren't bypassed with small polys, etc.

I've got my schemo and parts list ready for the phantom version, I'll report back when I'm done. By necessity, I will have to use axial electros, and I don't have room for poly bypass caps.

I'll see what I get.
Click to expand...

Right! What I'm saying is that the box for the battery in the tape op article has PLENTY room for the rest of the circuit. You just build it in there and then connect it to the capsule the same way.
 
Hey, PhilGood ,Do you happen to know the answer the the Question I posted above as you seem to know more about electronix than me and i"m sure it is a simple question it is the Answer I am haveing problems with??..LOL


ThanX
 
Minion said:
Hi, I was wondering if you of you guys could help me with a small problem I am haveing wireing up a Mic....

The problem is my Schematic doesn"t tell me which is the Negitive and the Positive lead when wireing the the 10uf Capacitor as electrolytics are Polarized and must be wired one way.....
Click to expand...

Positive lead of the cap should be wired to pin 2 from the mic.
 
PhilGood said:
Right! What I'm saying is that the box for the battery in the tape op article has PLENTY room for the rest of the circuit. You just build it in there and then connect it to the capsule the same way.
Click to expand...

OK then, we completely understand each other! :)

I ordered enough parts today to make 10 of my phantom version :) Hope they sound good :o
 
mshilarious said:
Positive lead of the cap should be wired to pin 2 from the mic.
Click to expand...


Umm...Sorry But I don"t understand what you mean as it relates to the Schematic above....

Looking at the Schematic above is the Positive lead on the Left or the Right??
(That way i will understand as it relates to the schematic)

ThanX

PS:Sorry for sounding stupid!! :(
 
Minion said:
Umm...Sorry But I don"t understand what you mean as it relates to the Schematic above....

Looking at the Schematic above is the Positive lead on the Left or the Right??
(That way i will understand as it relates to the schematic)
Click to expand...

To the left. Remember the stripe is on the drain (negative) side of the cap!
 
I've got a very N00b question:

What elements would be best suited for drum overheads?

Also, when ya'll speak of enclosing the electronics in silicon, do you simply mean wire it all together, put it in it's enclosure and fill it with silicon rubber?
 
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mshilarious said:
To the left. Remember the stripe is on the drain (negative) side of the cap!
Click to expand...


OK..Great, I"m glad I asked Cuz I though it was the other way arround because the wire that the cap goes on to is connected to the Negitive lead from the Battery so I though that the Negitive lead from the Cap should be closest to the Negitive Power lead from the Battery but I guess my Reasoning is flawed...I really appriciate the Help.... ;)



For Drum overheads you will probably want to use Omni-Directional Elements, they also have the Flatest Frequency responce....Omni"s Pick up Sound from all directions but are more Directional at higher frequencies and they seem to work well as Drum Overheads and Pick up the Cymbals really well.....

Get the 20hz to 20khz elements if you want the Widest frequency range but if you would Like to cut out some of the Lower frequencies you might try ones in the 100hz to 20Khz range or 200hz to 16Khz if you want to cut a Lot of the Lows and Highs....


Cheers
 
BIG QUESTION:

Ok, I've got yet another n00b-ish question. What is the point/function of the 10uf poly capacitor in this particular design? Guides I've found reccomend a 10uf/100V Metal Poly Cap...could I use a different cap? ;)
 
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