3 pronged mike

Hello all,

I got a second hand microphone the other day for recording interesting sounds on a little piano-key type mono tape recorder.

The mike is made by Grundig, model GDM 311 seems very well made, and looks like the sort your parents/grandparents might have used to record baby's words on the family reel to reel.

It has screen + 3 wires terminated in a 3 pin DIN plug, these are the outputs from some kind of matching transformer (I had a look) a low impedance side which seems to match the recorders input, and a higher impedance side. (I could only measure the DC resistance though)

So what I would like to know is, why the 3 wire arrangement? Is to provide an alternative match for a non standard input, or is it to provide some kind of offset earth connection - I'm guessing to feed a differential input.

Any suggestions, anybody? It would be nice to know even if I'm not going to use the extra wire.

Tia, Monster

--
Spam will eat itself
Reply to
Little Monster
Loading thread data ...

Some microphones I have seen have both high-impedance, single-ended outputs AND low-impedance, balanced outputs. This was back in the days when there were still high-impedance mic input requirements and when the concept of low-impedance, balanced was becoming accepted as the professional standard. The user was expected to wire the cable to tap whichever output was required.

Reply to
Richard Crowley

looks

provide

differential

going

Reply to
Arthur Jernberg

So, without removing the shield to have a look, could this be an auto-transformer sitting in there?

Monster

--
Spam will eat itself
Reply to
Little Monster

Given that most of the older Shure mics had a switch to select output impedance, yes.

Harry C.

Reply to
Harry Conover

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.