Chord IM07

Findlay

Member
I bought one of these Chord mics a few months back to see how good they are - at around £12 each in the UK they are a cheap alternative to an SM57. I must say I was pretty impressed - it is difficult to tell it apart from my 60's Unidyne III, which is a bit fragile and kept for special recordings. The only problem arose when I bought another and found it had been wired incorrectly. I figured this was the case when assigning each one to a different channel on my Tascam DP08 recorder - they sounded fine when the channels were panned hard left and right for stereo but when mixed for mono the bass was severely reduced and the overall sound was weird. Thinking they were out of phase I interchanged the hot and cold leads on the internal mic XLR connector on the new mic and everything was then fine. I had never realised how important phase was - which is a bit daft, as I know it it important when wiring speakers! But taking the mics apart I found that they had both been wrongly wired - with the cold lead also wired up to earth. I figured this was completely negating the advantages of using a balanced lead and pre-amp so snipped the cold to earth connector on each mic. They now sound great. Just wanted to check I haven't done anything silly here and whether this sort of thing was common with cheap mics?
 
Hi Findlay!

Polarity, (often called phase - not phase), is the same with microphones as it is with speakers.

If you have a single microphone or single speaker the polarity can be wrong but it's inconsequential. It's when you have a pair working together that an effect is seen and polarities must match.
Again, whether they're both right or wrong is largely inconsequential without reference to additional microphones or speakers.

If both of your microphones were wired 'wrong' but both in the same way, you shouldn't have observed a problem.
If that's how it was, revert the wiring so that both are the same, then check your cables for continuity from end to end, pin 2-2 and 3-3.
You may find that one of your cables is reversing polarity. That wouldn't be uncommon at all.


Edit: With regard to the tie to ground, I would have assumed it was there for a reason and should be left,
but I read a few threads on GS where guys said they lifted this tie for balanced operation.

Hope that's useful.
 
Hi Steenamaroo!

Thanks for your help on this. I'll check the cables too. I think I'll leave the tie to ground off for a while to see how things go. It seems to have removed some (very low level) hum so I think the balanced operation is working!

Thanks again for your previous help with the Unidyne III - it is still working well!
 
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