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Author Topic: AKG 414EB (brass ring) pops and hiss  (Read 2184 times)

afterlifestudios

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AKG 414EB (brass ring) pops and hiss
« on: August 05, 2016, 11:33:19 am »

Hi there.  I have a pair of AKG 414EB's (brass ring ck12's) that I use frequently for stereo applications.  They are well matched and sound fantastic.  One of them has occasionally exhibited some hissing and popping sounds (like distant a wind storm with a pop every few seconds).  The noise would only happen with the high pass switch engaged, and could often be stopped by scrolling the pattern selection switch.  So I always used it flat (no high pass) and it was silent, and I thought I'd be ok. 

But now even without the high pass engaged, the hiss and pops intermittently appear.  Any ideas about where to start my search for the fault?

Thanks in advance,
John
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klaus

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Re: AKG 414EB (brass ring) pops and hiss
« Reply #1 on: August 05, 2016, 12:58:50 pm »

Hello John,
One of the most frustrating aspects of my job is when a symptom is caused by more than one defect, as this might be the case here:
You may have a low-end cut switch with oxidized contacts (very common on this model) AND a contaminated capsule.

To isolate the latter symptom from the former, set the mic pattern switch to cardioid and the two rear switches to off (i.e. flat and no attenuation). Now perform the breath test (Google it). If it triggers the symptom or makes it worse, you have isolated one of the causes for the noise as capsule contamination.

Best of luck,
KH
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

afterlifestudios

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Re: AKG 414EB (brass ring) pops and hiss
« Reply #2 on: August 06, 2016, 04:07:02 pm »

Thank you, Klaus. 

Test results:

When I first connected the mic today, the signal was nice and clean.  (...as nice as MY voice can sound.)
Then I performed the breath test.  First breath or two, I couldn't make the capsule collapse and everything still sounded great.  So I gave it a nice strong steady "hhhhhhuuuuuuuhhhhhhhh" at very close range.  This collapsed the capsule, (a big "poof" sound like I'd hear when switching polar patterns).  Then the noise appeared.  (The solar wind).  As I type this, the solar wind is subsiding, but is still barely audible 3 or 4 minutes after the breath test.

How to proceed?  Do you clean ck12's?  (I dread to re-skin...)
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klaus

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Re: AKG 414EB (brass ring) pops and hiss
« Reply #3 on: August 06, 2016, 10:32:43 pm »

Capsule cleaning may be the solution.
Please contact me privately. I would like to keep the forum free of commercial intentions ands machinations (as much as that is possible in a world that doesn't seem to respect anything but money anymore).
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com
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