Intermittent "scrunch" on a AKG C 414 EB !!!

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I don't understand "scrunch"

Does it do this with voice with moisture from breath? Is the humidity high in the room it is used in

Could be a number of things

One it is used so the capsule might be dirty having leakage paths causing low output and noises or bad

Two bad or dirty connection at cable connector

Three maybe a bad part or solder connections

Does the capsule have a brass ring or is it the white plastic capsule?
If it is the brass one you might want to take it to a good pro to clean it if it is dirty and causing the noise.

Old capsules are tricky to clean without removing the gold. If it is a old brass ck12 I would be careful
 
I agree most of the time moisture affects a neumann style. Seth had a 414 he posted about that had a moisture problem that was fixed using agell pack. Maybe the moisture is inside the capsule?

Keith I am guessing you have seen old microphone capsules that were not cleaned for 20 years, that were coated with who knows what and they still worked(badly)

Some old capsules I cleaned were dirty around the whole capsule, edges, body etc so the cleaning was more than just the skin. What I was thinking with this AKG is maybe it is very dirty and there might be "nonstandard" leakage paths.
 
The caps seams to be perfectly clean. No dirt no visible moisture... It could be a brand new one you wouldn't know!!! It is unfortunately a platic caps not the mighty brass one.
I didn't try to unscrew the boards and check if there's a bad soldering somewhere but I'll do...
The "scrunch" noise is coming slowly, getting louder and louder and then it disappears and it starts again a few seconds or minutes later. This is why I thought about dead electrolytics...
There is also a big noise when i switch between the directivities... Really more than with my working c414eb.
 
Did you changed all the caps or only a few ones ?
I've found the schematic: look at the begining of this topic there's a link to another topic and the schematic is in the first page.

I love Prodigy Professional !!!!
 
Ok someone might have been inside the microphone, plastic CK12 for brass.

Finger oils/dirt Flux can mess up the high Z section of a condenser microphone.

Before you start changing caps blindly.

Get a few clean Q tips(USA term cotton ball on a plastic or paper stick)

Get some distilled water Place some in a very clean small cup etc.

Dip a q tip in the water and wipe the input caps and area around the Fets clean Use only once then toss. Get a new one and do this again toss it. Repeat this untill it is clean. Do not dip a used q tip back in the clean water.

If the capsule was changed where were the new solder connections made? At the capsule or at the board? Check for flux. Flux is very bad around a high z spot in mcrophones. I use 91% isopropyl alcohol and a number of clean q tips to clean flux off PCBs

Leakage of the capsule charge can sound like bad caps. I would make sure that every thing is very clean before changing parts.

If cleaning around the fet input and caps and pads switch does not help Check the dc to dc section next

http://www.geocities.com/SiliconValley/Peaks/5212/start.htm
 
buttachunk my cleaning post was for lolo-m.

I agree caps can go bad. Cleaning is easy compared to changing parts and then cleaning the boards again. Tants seem to often fail as a short, I don't remember any going bad tants they seem to fail like switches working/shorted or burned and smoking.
So maybe the noise making caps are the other ones?

If it is the tants Slowly Going Bad I would like to understand the failure inside the caps. That would be interesting
 
Before changing everything I tried again my 414...

First, I found weird the Low Cut switch. I coundn't feel the different positions. So I took it out and gave it a new life...

Then I checked the different voltages of the caps and found them really low... I was checking the mic with an old desk, so I decided to try with another preamp. And It works !!! I don't really know what was the problem (low cut switch or bad phantom power or maybe both) but now it works !!!

I'm maybe the luckiest guy of the world... I bought a working 414 on E(vil)bay and the seller offered me to buy a non working one for 300€... And here it is, it works ! But checking the capsule voltages, I realised it wasn't a new CK12. I don't know if it's a brass capsule but it can be... The sound is similar to a C-414-TLII but there's something more. A kind of magic definition of the hi mids and highs. Don't you know where I can see pictures of a real Brass CK12 ???
 
I'M THE LUCKIEST MAN OF THE WORLD !!!! :razz:

I record voices with it and I understand now what's the diference between the brass caps and the new one : magic . :green:
 

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