Do all microphones can produce balanced signal?

IronWine

Member
Hey fellas

i have acquired some old quirky consumer microphones in the past months. some of them has TS connector, some have DIN, all with fixed 1m-5m cables.
I wish to mod all of them to have female xlr socket (and a 5cm cable i guess), so i can simply connect them with any xlr cable.

that made me wonder:
some of them utilize TS plug, having only 1 conductor and a shield.
What i know about dynamic microphones, is that 2 wires are connected to the coil that is moved in an analog way to that of the diaphragm. then it goes to a transformer, and then to the plug.
so, basically, every mic need to have +,- and shield (balanced signal) . if thats the case, how is the "unbalancing" of the signal occurs inside the mic?
how can i make the balance mod i wish on all these old mics?

cheers
 
Hi there,

There are a few things to take into account.
The presence of a transformer in a dynamic microphone is probably more often to do with isolation or impedance rather than balancing.

A moving coil microphone with positive and negative wired as such, and its chassis grounded, is balanced, like my old transformer-less AKG D12,
whereas a moving coil with +ve as signal and -ve as ground is not.

Wiring the former to XLR is/should be fine whereas wiring the latter to XLR and accidentally exposing to phantom power would be bad news.
This is because +and- are floating at the same potential relative to ground in scenario one, whereas one of them is tied to ground in scenario 2.

I suppose the thing to work out, at this stage, is whether you want these microphones to be balanced, or if you simply want them to be XLR equipped.

In the example of that d12, it's simply coil negative to negative, coil positive to positive, and metal chassis to ground.
 
Hi there,

There are a few things to take into account.
The presence of a transformer in a dynamic microphone is probably more often to do with isolation or impedance rather than balancing.

A moving coil microphone with positive and negative wired as such, and its chassis grounded, is balanced, like my old transformer-less AKG D12,
whereas a moving coil with +ve as signal and -ve as ground is not.

Wiring the former to XLR is/should be fine whereas wiring the latter to XLR and accidentally exposing to phantom power would be bad news.
This is because +and- are floating at the same potential relative to ground in scenario one, whereas one of them is tied to ground in scenario 2.

I suppose the thing to work out, at this stage, is whether you want these microphones to be balanced, or if you simply want them to be XLR equipped.

In the example of that d12, it's simply coil negative to negative, coil positive to positive, and metal chassis to ground.

thank you for your input!
well, i do want to make them into balanced microphones.

so, having said that the coil has a negative and positive sides, i still can't understand how only one conductor(and shield connected to chassis) goes out of a microphone ?
does that means that in that case of old consumer microphones, a balanced signal (+,-) going out of the coil, into the transformer and an unbalanced signal is goint out of it to a 1/4" plug?

can i actually take any moving coil microphone, no matter what it's current configurations, and make it into a balanced microphone?
 
thank you for your input!
well, i do want to make them into balanced microphones.

so, having said that the coil has a negative and positive sides, i still can't understand how only one conductor(and shield connected to chassis) goes out of a microphone ?
does that means that in that case of old consumer microphones, a balanced signal (+,-) going out of the coil, into the transformer and an unbalanced signal is goint out of it to a 1/4" plug?

In the case of old consumer microphones it's probably more like that they've just wired capsule + and - as signal and ground.
In that case, if the chassis is metal, capsule negative would probably be tied there too.

can i actually take any moving coil microphone, no matter what it's current configurations, and make it into a balanced microphone?

I believe so. Would be nice to have an authority confirm but I'm fairly sure taking + and - from a capsule into pins 2+3 of XRL is balanced.
The ground/pin 1 would generally be tied to the microphone chassis+basket/grill.
 
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Just drop the transformer out of the circuit shown below of an SM58 and it should give a balanced connection to the mic. Having the 'ground' of the cable connected in any way to the coil of the capsule might prove not too healthy for the mic if phantom power got accidentally applied.
 

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