Is the AKG D-202E cardioid dynamic microphone balanced?

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I'm looking to see if the AKG D-202E cardioid dynamic microphone is balanced. I've read that balanced microphones have transformers within them and XLR isn't a sure fire way to know that they are. I'm looking to use it with a Peavey PV 10 USB Mixer, so I'd like to know if I can use it with condenser mics with phantom power on at the same time.


http://lcweb2.loc.gov/master/mbrs/recor ... ophone.pdf (http://lcweb2.loc.gov/master/mbrs/recording_preservation/manuals/AKG%20D-202E%20Two-Way%20Cardioid%20Dynamic%20Microphone.pdf)

https://assets.peavey.com/literature/ma ... -14-20.pdf (https://assets.peavey.com/literature/manuals/PV10-14-20.pdf)


Thanks,

John

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Hi John. So far as I can tell, according to the akg spec sheet the mic output is balanced and ought to survive phantom power without damage.

A balanced xlr would send identical but 180 degree out-of-phase signal into pins 2 and 3, and it would not use pin 1 for signal purposes, only for ground shield. In other words when positive voltage appears at pin 2, then the equal negative voltage appears at pin 3, and vice-versa. When negative voltage appears at pin 2 then the equal positive voltage appears at pin 3. That is why it is "balanced" the two pins are carrying exactly the same signal except they are mirror images of each other.

So a balanced input subtracts one input signal from the other to amplify the difference between them. So if pin 2 and pin 3 are both peaking at +/- 1 volts, then the amplified output difference after subtracting one input from the other would be +/- 2 volts at the peaks. When one input is +1 then the other input is -1, and (+1 - (-1)) = +2. Then when the inputs switch polarity, it is (-1 - 1) = -2.

However any hum picked up by the cable is likely to be the same amount of hum on both signal wires. So if the cable is picking up +/-1 volt peak-to-peak of hum, on the positive hum half cycle the difference is (1 - 1) = 0. And on the negative hum half cycle the difference is (-1 - (-1)) = 0. So the balanced circuit tends to cancel out any noise that is about the same on both signal wires in the mic cable. This is called Common Mode Rejection.

On page 14 of that Peavey manual, it shows the phantom power +volts connected thru the same value resistor to both pin 2 and 3. Because your akg mic apparently does not have a connection between either pin 2 or 3 and ground on pin 1, then no phantom power should flow thru your capsule coils, heating them up or burning them out. If there is +48 volts on pin 2 and also +48 volts on pin 3, then there is the same DC voltage on both ends of the capsules, so I don't see how any phantom current would flow thru the mic and damage it.

A mic designed to use phantom power to power a built-in preamp circuit as with most condenser mics, the mic would take its +48 volts from pins 2 and 3 to connect to the little built-in circuit board, and it would connect the power supply ground of the little built-in preamp circuit board to pin 1. Thereby drawing "conventional current" power in from pins 2 & 3, thru the circuit board, and out to pin 1.

But your AKG circuit doesn't show any kind of connection between pin 1 versus pins 2 and 3, so it doesn't look like any phantom power current could flow in that case.

It would be the same even with a balanced mic which uses a transformer. The transformer output would connect to pins 2 and 3. If equal phantom power voltage is applied to both terminals of the transformer output coil and there is no other path to pin 1, then no current will flow thru the transformer, because the voltage would need to be different between the two transformer outputs for current to flow thru the transformer. To get current to flow, whether you have a transformer or not, you would need something like +48 volts on one pin and +49 volts on the other pin or whatever. Some kind of DC voltage difference between pins 2 and 3.

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Stop worrying. XLR mic connections with phantom power is an industry standard.

If there was any risk for the mic not being able to handle phantom power, it should say so in bold capitals on page 1 of the owners manual.
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