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Post by timcampbell on Jun 1, 2023 12:07:20 GMT -6
Well I am going to open up a can of worms. Over the years a few well known microphone gurus have pushed the notion that no capsule with new membranes can ever sound as good as it originally did from the factory. This just is not true no matter what anyone tells you. Repairing a membrane is no different than changing a capacitor in the sense that if you use the right components , following the proper method and measure acurately the results will be the same as the original or better given that not all old capsules sounded good..
It could be argued that no one possesses the original material or that the old methods were not passed on, tuning frequencies, glue, blah, blah, blah but that is someone speaking from a position of not knowing themselves. With the proper procedures all of these unknowns can be imperically determined and replicated. Proper tools measure acurately and any great engineer who spends all their time listening to sound as a quality's ears are equal to or better than a mic guru's.
I was lucky in that when I was starting building capsules AKG was a very honest, helpful company. Karl Peschel and Norbert Sobel were so informative about materials and procedures that it helped immensely with my work. I was able to source original materials and follow the right procedure.
In my time working on capsules I have seen some terrible repairs done by technicians but I have also seen a lot of brilliant work done by people like Thiersch, Peter Drefahl, Herbert Haun, etc. You could find similar examples in any repair segment.
Recently I have seen the price of beat up old CK12 capsules skyrocket to 1000s of dollars just because they are all original with the buyer not knowing if they are working accurately or not.
Here is my latest example: I was sent 11 all original AKG CK12 capsules that were working but with various problems. These capsules ranged in sound from dull to piercingly bright. I was able to retain the original membranes on 5 of the capsules and replaced membranes on the other 6. All of these capsules were completely broken down, cleaned and reassembled to spec. I matched all these capsules to within less than a half dB in frequency and amplitude. You could easily pick any 2 at random for a matched pair.
If you need a repair to a capsule find a tech you trust and ask him to verify his work when it's done and enjoy your repaired capsule without all the handwringing. There are a lot of old, crappy sounding original capsules out there.
As a disclaimer I am not using this as a plug for my work. I am much too busy and don't want to take on more repair work.
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ericn
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Post by ericn on Jun 1, 2023 12:45:24 GMT -6
Tim the problem was always finding someone you could trust with a CK12 to not only repair it but actually return your capsule to you!
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Post by chessparov on Jun 1, 2023 13:15:17 GMT -6
Does it work even for Meme Brains like mine. Reskinned? Sounds scary!  I'm always on the hunt for new material... Chris |
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ericn
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Post by ericn on Jun 1, 2023 13:19:07 GMT -6
Does it work even for Meme Brains like mine. Reskinned? Sounds scary! I'm always on the hunt for new material... Chris Hey since I’m 97% reskinned I am offended by the “ scary”😁 The Question for Tim is does that make me the human 251?😎 |
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Post by bgrotto on Jun 2, 2023 8:49:30 GMT -6
This thread is batting a thousand. Great work to everyone involved!
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Post by paulcheeba on Jun 2, 2023 11:46:15 GMT -6
Michael Amon’s FB page and website look cool. I’ve been trying to buy some Real CK12 but he said he can’t spare any. He calls it reconing and apparently says the high end is omni in the old ones which is why they sound so airy and open. I can’t verify that. Can you Tim?
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Post by Ward on Jun 2, 2023 12:10:25 GMT -6
Michael Amon’s FB page and website look cool. I’ve been trying to buy some Real CK12 but he said he can’t spare any. He calls it reconing and apparently says the high end is omni in the old ones which is why they sound so airy and open. I can’t verify that. Can you Tim? does the sound about right? |
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Post by timcampbell on Jun 2, 2023 13:13:01 GMT -6
Michael Amon’s FB page and website look cool. I’ve been trying to buy some Real CK12 but he said he can’t spare any. He calls it reconing and apparently says the high end is omni in the old ones which is why they sound so airy and open. I can’t verify that. Can you Tim? does the sound about right? There must be some misunderstanding here if we are discussing cardioid. I know Michael and I'll ask him what he meant. In order to acheive directionality we cancel out mid and high frequencies from the rear.
This is very easy to observe yourself. Put any CK12 into cardioid and speak into the rear membrane. There is nothing omni about the higher frequencies.
This is from a CK12 vr but it shows typical directionality
This graph also clearly shows the difference between older and newer CK12's. The older capsules have rise from 7khz up to 12khz that this modern capsule does not have.
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Post by paulcheeba on Jun 2, 2023 13:18:30 GMT -6
There must be some misunderstanding here if we are discussing cardioid. I know Michael and I'll ask him what he meant. In order to acheive directionality we cancel out mid and high frequencies from the rear. Bass is always omni.
This is very easy to observe yourself. Put any CK12 into cardioid and speak into the rear membrane. There is nothing omni about the higher frequencies.
That is what I thought as it’s muffled round the back of a cardioid signal. BTW that conversation was with a third party. Not myself. The third party that recommended Michael was a serious pro so maybe it just got lost in translation. I don't see why you'd need to follow it up. |
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Post by markfouxman on Jun 2, 2023 13:20:14 GMT -6
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Post by mics on Jun 2, 2023 18:12:44 GMT -6
I’ve got to say, I agree wholeheartedly with everything you have said Tim! If done right, there is no black magic, just time and effort.
It’s an interesting thought, Tim and I were spitballing at Namm and discussing the fact that both he and I have made more ck12 capsules than we’re originally made by AKG. With numbers like that and the know how too, of course a vintage era capsule can brought back to life. Disclaimer “I too, have too many projects on the run and do not wish to take in repair work at this time. Just new capsules”
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Post by cserrano on Jun 2, 2023 18:20:13 GMT -6
Tim, thanks for this awesome post! While of course such a post can't help but promote your own work and skills, which are quite impressive, sharing your experience still helps others. So thank you for that. I also want to say that my experience with LDC capsules leads me to agree with you. While I myself do not membrane capsules in the Serrano Audio microphones, I have worked with several who do this and I have been impressed with what is possible. I have even heard capsules that, to my ears, have surpassed genuine Neumann K87 capsules in certain respects. Similar to you, while developing the Serrano 84, my experiments lead me to different conclusions than what some other microphone gurus have said about SDC capsules. We live in an amazing time when the knowledge of how to build the best quality of microphones in the world is not exclusive to a small handful of people.
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Post by mics on Jun 2, 2023 20:20:02 GMT -6
Tim, thanks for this awesome post! While of course such a post can't help but promote your own work and skills. Not to be a stick in the mud but…… I don’t think Tim was trying to promote his own work. He clearly stated he is too busy to accept any work. Sometimes we just like to post. Just because! Let’s face it; before we were “gear makers”, we were “gear heads” |
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Post by tackhouse on Jun 2, 2023 22:28:56 GMT -6
(As a happy owner of a STAM 251, a pair of BeesNeez B67-269’s, and a pair of Serrano Vintage 87’s, I’m digging this thread. All outstanding microphones, and my hat’s off to each of you!)
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Post by cserrano on Jun 2, 2023 23:24:26 GMT -6
Tim, thanks for this awesome post! While of course such a post can't help but promote your own work and skills. Not to be a stick in the mud but…… I don’t think Tim was trying to promote his own work. He clearly stated he is too busy to accept any work. Sometimes we just like to post. Just because! Let’s face it; before we were “gear makers”, we were “gear heads” I totally agree he clearly had no intention of promoting himself! My comment was an attempt to humorously point our the irony that even when he's clearly not trying to promote himself by sharing his experience, what he shared was so inspiring that one cannot help but be interested in his work, even if he doesn't want anymore. I think what Tim's shared and what you echoed is truly a necessary and helpful contribution to the discourse we all love! |
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Post by mics on Jun 2, 2023 23:29:55 GMT -6
Not to be a stick in the mud but…… I don’t think Tim was trying to promote his own work. He clearly stated he is too busy to accept any work. Sometimes we just like to post. Just because! Let’s face it; before we were “gear makers”, we were “gear heads” I totally agree he clearly had no intention of promoting himself! My comment was an attempt to humorously point our the irony that even when he's clearly not trying to promote himself by sharing his experience, what he shared was so inspiring that one cannot help but be interested in his work, even if he doesn't want anymore. I think what Tim's shared and what you echoed is truly a necessary and helpful contribution to the discourse we all love! 👍🏽 |
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Post by opr on Jun 3, 2023 2:14:54 GMT -6
Here here! My sentiments exactly! It can and has been done for many years now,not that it's a dismissively simple thing to do, as you still need throw many thankless hours at the task in order to gain the knowledge and methods in order to get good results... Particularly when it comes to Ck12 capsules. I also concur Vintage AKG capsules can be all over the shop from widely varying diaphragm resonances and capacitance anomalies to lapping and tuning inconsistencies. I repaired a C12a capsule only last week that such issues! I also am not pluging a Ck12 repair service as I'm busy making my own.
Checkout the poor lapping job on this capsule....
post repair
Well I am going to open up a can of worms. Over the years a few well known microphone gurus have pushed the notion that no capsule with new membranes can ever sound as good as it originally did from the factory. This just is not true no matter what anyone tells you. Repairing a membrane is no different than changing a capacitor in the sense that if you use the right components , following the proper method and measure acurately the results will be the same as the original or better given that not all old capsules sounded good.. |
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Post by hadaja on Jun 3, 2023 3:14:43 GMT -6
What are we looking for in regards to lapping Mark? Or i should say what is lapping?
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Post by opr on Jun 3, 2023 3:22:07 GMT -6
What are we looking for in regards to lapping Mark? Or i should say what is lapping? Hey Dale, Lapping is the process of making an object precisely flat. The darker area's of the back-plates are where proper contact was made with the lapping machinery's lapping plate and the brass colored area is where it didn't quite make it to flat.
It's a bit more obvious from this angle. |
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Post by mics on Jun 3, 2023 4:17:22 GMT -6
Hi Guys help a dummy out here! How do I post pics? I’ll post a few and explain some stuff.
Cheers
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Post by opr on Jun 3, 2023 4:22:17 GMT -6
Hi Guys help a dummy out here! How do I post pics? I’ll post a few and explain some stuff. Cheers Hey Ben, Click the insert Image icon and paste in the Image link. |
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Post by mics on Jun 3, 2023 4:39:49 GMT -6
Hi Guys help a dummy out here! How do I post pics? I’ll post a few and explain some stuff. Cheers Hey Ben, Click the insert Image icon and paste in the Image link. Doesn’t seem to show up on my iPhone. |
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Post by opr on Jun 3, 2023 4:58:25 GMT -6
Hey Ben, Click the insert Image icon and paste in the Image link. Doesn’t seem to show up on my iPhone. Might be easier on a desktop or laptop. |
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Post by mics on Jun 3, 2023 5:06:09 GMT -6
Ok let's try this from a laptop. Here is a picture of the two types of lapping. The left is chemical Lap, this is done by mixing certain chemicals and oils. The second is a Media lap. This is done using Lapping media and Lapping oil. Both are equally flat to within a micron. which one to use is more of a choice thing and machine dependant. Attachment Deleted |
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ericn
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Post by ericn on Jun 3, 2023 9:20:05 GMT -6
Ok let's try this from a laptop. Here is a picture of the two types of lapping. The left is chemical Lap, this is done by mixing certain chemicals and oils. The second is a Media lap. This is done using Lapping media and Lapping oil. Both are equally flat to within a micron. which one to use is more of a choice thing and machine dependant. View AttachmentLike small children I have to admit a personal preference for the shiny one on the left.🤪 |
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