Using a low-Z unbalanced mic

Discuss your workplace, instruments, amps, and any other gear.

Moderators: khz, MattKingUSA

Post Reply
Established Member
Posts: 189
Joined: Tue May 20, 2014 2:01 pm
Location: Tennessee, USA

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.


Established Member
Posts: 163
Joined: Sun Apr 28, 2013 5:36 am

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.

The Quintar Project:
- Popularizing an all fifths tuning for guitarlike instruments
- Youtube: Playing and Building
- Files: Sourceforge

Post Reply