AKG CK12 Teflon Repair and surprise
« on: May 22, 2020, 06:42:04 AM »
Hi,
I would like to share a very instructive story.
I've recently repaired two Teflon Ck12.

Both was bad sounding, in par with their reputation.

After a complete dismantle, i found that a very important part was completely destroyed (aging).

The spacing foams under the diaphragm were rotten, thus the factory gap between teflon and backplates (thus also between membranes and backplates) was unreliable...
You can see the foam residuals in the upper right side of the picture...
So i've cut some spare ring foams and after a good cleaning, i've rebuilt the capsules.
After some adjustments (checking the polar patterns) on the position of the screwed diaphragm, i as very surprised with the result.

There was a massive improvement on the sound quality, and matching sides...

i would say a little darker than Brass CK12 , but not that far in terms of overall quality...

Regards
Fred

http://www.saturn-sound.com/Curio's/akg's%202072%20z%200009%20capsule.htm
« Last Edit: May 22, 2020, 06:55:05 AM by granger.frederic »


Re: AKG CK12 Teflon Repair and surprise
« Reply #1 on: May 22, 2020, 09:37:03 PM »
Awesome. Thanks.

I have also had success in the past using an insulated spring wire and winding a spring that keeps pocket size constant.  Result was nice and I agree, not bright but certainly not horrible either ;)

gyraf

Re: AKG CK12 Teflon Repair and surprise
« Reply #2 on: May 23, 2020, 04:53:26 AM »
Aah, very interesting development indeed - can explain some mysterious changes over time that seem unrelated to anything seen by the naked eye.

How hard is is to take apart without destroying the membranes? Method?

/Jakob E.
..note to self: don't let Harman run your company..

Re: AKG CK12 Teflon Repair and surprise
« Reply #3 on: May 23, 2020, 10:16:12 AM »
Aah, very interesting development indeed - can explain some mysterious changes over time that seem unrelated to anything seen by the naked eye.

How hard is is to take apart without destroying the membranes? Method?

/Jakob E.

Not too difficult at all.  I use a tool that i made .  I turned a pei e of brass to the right size.  It needs to have a really thin sharp wall.  Then mill away half of it so it looks like a half moon.  The wall can only be about 300um in order to fit inbetween the ring and teflon wall.  Push in gently and lever the membrane out.  I’m sure a small screw driver could do it also but it will bruise the teflon due to the fulcrum load on the teflon.

🤓

Re: AKG CK12 Teflon Repair and surprise New
« Reply #4 on: May 23, 2020, 05:31:47 PM »
you can also  unclip the diaphragm by pulling it  gently with a clamp, thanks to the front pin...
it comes easily
then , you have to unscrew  the removable half of "Teflon" capsule frame
Done...
the more i use this capsule now, the more i like it, especially in front of a guitar amp, but also with my voice...
i recommend to all the Teflon ck12 owners, to repair them if they noticed a sound  degradation...
« Last Edit: May 23, 2020, 05:43:19 PM by granger.frederic »


 

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