Using a low-Z unbalanced mic

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Using a low-Z unbalanced mic

Post by lykwydchykyn »

I recently repaired an antique dynamic mic (Allied M3311) that was given to me by a family friend. It's unbalanced (2-conductor) and low-Z (10k ohm).

If I plug it directly into an unbalanced input on my mixer, I have to crank the trim and the gain, and the hum is unreal.

If I plug in to a directbox, the hum is gone, but I still have to crank the gain. I'm also pretty sure the DI box is meant for high-Z inputs like guitars, so I'm not sure if the impedence mismatch is screwing with the sound.

In a nutshell, my gear seems to be designed for low-Z balanced or high-Z unbalanced, but not low-Z unbalanced.


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Re: Using a low-Z unbalanced mic

Post by Broomy »

Bit late to the party, but here's my two cents.

Problem with your mic is that it has a relative high Z (low is considered <1k), comparable with a humbucker pickup, but with an output level of a mic.
When using a DI-box, you get a balanced, low Z signal, but the level of your signal is even less.

Depending on how much you want to spend on it, you could use a buffer (google on Till preamp), which gives a +3dB and lowers the impedance to 2.2K. Or if you have a balanced line input, there are 1:1 DI-boxes available you could try.
Moneywise it may be a better plan to discard this mic and buy another one.

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