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Hum noise in Akg's p170

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Hum noise in Akg's p170

Postby gmdavila » Sat Jan 23, 2021 7:43 pm

I bought the Drum Set Session I which comes with 2 p170, but one of them is significantly noisier than the other. The noise is around 50hz and i believe that is ground noise, but I don't understand why one of them is louder than the other. I already tried to change the cables, inputs but the noise is still louder in one of the mics. Sometimes the noisier mic makes a different noise too, as if it was touching the clothes. I just want to know if this is due to a common difference between these mics or if I need to return them.

Here are some examples of the difference between the mics noises:
https://prnt.sc/xigy87
https://prnt.sc/xigzib

Any help would be appreciated!!
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Re: Hum noise in Akg's p170

Postby blinddrew » Sat Jan 23, 2021 9:44 pm

Sounds like there may be condensation on the capsule. Wrap them in a dust-proof bag and dry them out in a warm space like an airing cupboard for a day or so and see if that improves the rustling sound.
The 50Hz sound might be a ground loop.
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Re: Hum noise in Akg's p170

Postby Hugh Robjohns » Sat Jan 23, 2021 11:15 pm

The mic is clearly faulty, so if you've bought it recently you should contact the retailer and arrange for a replacement as it is clearly not fit for purpose.

Constant hum suggests a problem with the mic body's internal grounding, and rustling suggests a contaminated capsule or faulty impedance converter circuitry. By swapping cables and preamps, and comparing the performance to its sibling you've confirmed the problem is with the mic and not external factors.
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Re: Hum noise in Akg's p170

Postby gmdavila » Sun Jan 24, 2021 12:14 am

Thank you so much for the quick answers!!!
Since I bought the mics this week I'll contact the retailer for the replacement.
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Re: Hum noise in Akg's p170

Postby Hugh Robjohns » Sun Jan 24, 2021 2:29 am

:thumbup: good plan.

I'm not entirely convinced AKG's product QC is what it once was...
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