New diaphragms and voice coils for vintage German mics?

[smilan]

Earlier today I pulled a D12 mic out for a session and it was dead...
One end of the voice coil has broke.
I was managed to repair the broken voice coil by taking out one turn and solder it to to the output wire.
Now I have another D12 with a broken capsule where the voice coil has completely detached from the diaphragm and can't be repaired.
During the years I saw many old German mics (mostly MD421 / MD21 / D12) with broken capsules that went out of service. So I'm wondering why a replacement diaphragms and voice coils aren't being made no more?
I guess that any manufacture who build dynamic microphones can easily produce those spare parts.
If someone here have any connection to microphones companies please ask them to think about this idea.

 

[Whoops]

During the years I saw many old German mics (mostly MD421 / MD21 / D12) with broken capsules that went out of service.

Yes, you're correct there's thousands and thousands of AKG D12 and variants (D20, D22, D25, D30, D36, D40, D45) and also Sennheiser MD421 that are useless due to damaged diaphragms or voice coils.
A cheap but correct diaphragm and a good installation would bring those mics back to life and service.

So I'm wondering why a replacement diaphragms and voice coils aren't being made no more?

That has been talked before, you are not the only that questioned that. so you're not alone.

I guess it still didn't happen because no one yet wanted to have the work, didn’t have enough time, patience and financial resourced to make it happen.

A professional CAD drawing of the diaphragms with all the correct measures (shapes and radius) would be needed. Plus also all the specs of the voice coil.

Then you would need to talk to a factory/capsule manufacturer to produce this, I guess for them it would be quite an easy job. The problem might be the minimum quantities needed for them to do a custom job like this, as they will not do it in small quantities, so the initial financial investment for this adventure can possible be high.

But I guess it all depends of having all the correct specs and CAD drawings and asking around for price quotes.

Then after the initial sample productions you would have to test the samples and do some quality control. Maybe also some back and forth with the factory to make it perfect.

After that you need to have a way to distribute and sell these diaphragms to costumers.

It's totally feasible and it might happen but there needs to be someone that wants to take on this adventure

I guess that any manufacture who build dynamic microphones can easily produce those spare parts.

For sure, and there are many companies manufacturing Dynamic capsules, a lot of good ones in China, if not all.

If someone here have any connection to microphones companies please ask them to think about this idea.

If you want to inquire companies and pursue in this adventure I could try to help you out and could put you in touch with someone very experienced in these diaphragms and in fixing these mics.

 

[12afael]

Someone have any idea how the coil is made? What kind of core is used?

 

[beatnik]

it's an air wound coil

 

[12afael]

I mean it have to be wound around something and then released from the core. But how because the coil is very fragile.

 

[Khron]

Teflon / PTFE perhaps? At least because it's one of the least sticky materials we have?

 

[Whoops]

I mean it have to be wound around something and then released from the core. But how because the coil is very fragile.

It's the same type of coil winding that speakers have attached to the cone.
I've seen people re-wind speakers by hand and they do it around paper and after it's wound they release the paper. But in this case it has to be done in a factory so they will have a more industrial and precise way of doing it.

How it's wound it's not a problem for a dynamic capsule manufacturer they already know pretty well how to do it, they do diaphragms, coils and capsules all day for many years.
How they do it or not it's not an issue here.

 

[Drosselmeier]

https://groupdiy.com/threads/akg-d12-diaphragm-source.73296/

 

[Whoops]

https://groupdiy.com/threads/akg-d12-diaphragm-source.73296/

Thanks for the link,
I remembered we had this conversation in the past but I didn't remember the thread name

 

[soliloqueen]

i wouldn't mind looking around to see what can be done about this after my condenser capsules are out

 

[12afael]

I haven't seen many coils but the ones I have seen don't have any paper and the wire is very thin hold just by the varnish/glue.

I know factories can do it. still I found it interesting and I would like to know how.

if you want to widen your opportunities Headphones manufacturers have to use very similar techniques.

 

[smilan]

I wrote to AKG (Harman) and as I predicted this was their answer:

"If you are referring to the legacy D12:
https://www.akg.com/on/demandware.s...atalog_Harman/default/dwe1cf0ad8/pdfs/D12.pdf

It is simply too long beyond production to make it economically feasible to create small production runs of replacement components for an item that has been obsolete for such a length of time. Even if we still possessed the tooling, the low demand and small batches would make it impractical."

 

[David König]

Yes, you're correct there's thousands and thousands of AKG D12 and variants (D20, D22, D25, D30, D36, D40, D45) and also Sennheiser MD421 that are useless due to damaged diaphragms or voice coils.
A cheap but correct diaphragm and a good installation would bring those mics back to life and service.



That has been talked before, you are not the only that questioned that. so you're not alone.

I guess it still didn't happen because no one yet wanted to have the work, didn’t have enough time, patience and financial resourced to make it happen.

A professional CAD drawing of the diaphragms with all the correct measures (shapes and radius) would be needed. Plus also all the specs of the voice coil.

Then you would need to talk to a factory/capsule manufacturer to produce this, I guess for them it would be quite an easy job. The problem might be the minimum quantities needed for them to do a custom job like this, as they will not do it in small quantities, so the initial financial investment for this adventure can possible be high.

But I guess it all depends of having all the correct specs and CAD drawings and asking around for price quotes.

Then after the initial sample productions you would have to test the samples and do some quality control. Maybe also some back and forth with the factory to make it perfect.

After that you need to have a way to distribute and sell these diaphragms to costumers.

It's totally feasible and it might happen but there needs to be someone that wants to take on this adventure



For sure, and there are many companies manufacturing Dynamic capsules, a lot of good ones in China, if not all.



If you want to inquire companies and pursue in this adventure I could try to help you out and could put you in touch with someone very experienced in these diaphragms and in fixing these mics.

Hi, I am fixing these old mics for decades and I would be grateful if you know any contact to any manufacturer of diaphragms and coils.

 

[Whoops]

Hi, I am fixing these old mics for decades and I would be grateful if you know any contact to any manufacturer of diaphragms and coils.

Basically any Chinese manufacturer of dynamic mics or dynamic mic capsules.

I remember there were 2 well know Chinese manufacturers of Dynamic capsules and condenser capsules, but I don't remember the name at the moment, maybe someone around here will know.

Microphone manufacturers there's a lot of them,
from the top of my mind:
Beijing 797 Audio
Takstar
AYM Microphones
Feilo
Feng Lei
Everlux
Shuaiyin

there's much more for sure

 

[AustinMics]

Jan, 2023, work-in-progress on my thought project: 50+ hours attempting to fabricate hand-made replacement AKG D12 diaphragm(s?) in the USA.

Lo-Fi tooling and proof-of-concepts seem promising, but zero-budget "fail, learn, repeat" is my technique. Probably months from a working prototype, and at least a year away from anything repeatable... If repeatability is even possible!

 

[Daniel Faustino]

Hello guys, I'm new to this conversation, finally had the time to research some solutions for my D12, 421 and bf509.
@AustinMics did you had any success with your attempts?
I am also wondering, what characteristics does a manufacturer need to make one of this diaphragms?

 

[David König]

If you have problems with any of these vintage mics you may sell them to me for reasonable price or I can repair them for you.

 

[Daniel Faustino]

If you have problems with any of these vinrage mics you may sell them to me for reasonable price or I can repair them for you.

Thank you, but if there's a possibility to fix it, I wanna do it (diy brain problems, right? Ahah).
Besides, I entered in the world of making classic condenser clones earlier this year, so wanna keep on learning.
But if you know any supplier for this I would very thankful.

 

[David König]

I wish I know any suplier but nope, AKG does not have any parts for years.
I don´t know if it is possible to fix it before I have it in my hands. Sometimes the diphragm itself hartened during the years and you cannot do anything with it. But since I do it for living I can use unfixable mics as source of spare parts.

 

[Whoops]

But since I do it for living I can use unfixable mics as source of spare parts.

Hi David,
Nice to meet you.
It’s great to know more people that fix dynamic mic capsules.

How can we know more about your work?

Thanks
Best regards