AKG D12 microphone repair..if it is possible at all..

[Studiogearlover]

hello guys. I would like to ask anyone out there who ever did repair an AKG D12 vintage microphone. I have found one in a bad shape and went for it for the fraction of the usual street price. I knew that either will work or not... well.. no signal. I took it apart. Someone had been here before many times as the plastic was broken, the screws were missing holding the grill...all of them. Glued here and there. Inside looks OK kind of besides the soldering of the mic cable. I am not sure what I am seeing here is what supposed to be when you look at the capsule where the green and blue leads are, seems to be just hanging there ? There is no resistance measured and there is no continuity measured between the blue and green leads.

I am no expert here but I do not see where the coil is connected to these leads and I assume somewhere should be connected?

Appreciate your help with massive thanks!

 

[beatnik]

Measure resistance between blue and green wire on the terminal strip. A healthy diaphragm would read close to either 60 ohm or 200 ohm depending on the coil version.
If you have an open reading, chances are the coil is damaged, but sometimes it's just the wire that need re soldering.
There is a large thread about the D12 with lots of information on how to remove and service the diaphragm, search the forum

 

[Studiogearlover]

Thanks Beatnik... measuring zero resistance between the blue and green wire.... i did not remove the felt cover of the diaphragm but maybe the coil is not soldered to these connection points? I have not ever dealt with this mic so I am just guessing.... i would love to make this mic re born for my bass drum : (

 

[adamasnan]

Andreas Stenzel can probably do it!

@slqzy on Instagram

 

[panman]

So, why don`t you just search this forum and easily find out who is able to fix these microphones and not only "probably"?

 

[s2udio]

Studiogearlover​

Try this link
https://web.archive.org/web/20150319144657/http://groupdiy.com/index.php?topic=33755.40

 

[L091c]

Try this link

S2udio, I just noticed that you wrote that step by step guide! I used it to revive my left for dead D12 back in 2018. It is still going strong, thanks a million!
View attachment IMG_2711.mp4

 

[Whoops]

Esa Tervala, panman in this forum is the most experienced person around in fixing D12 mics (and related). Probably one of the most experienced people in the World if not actually the most experienced.

Like he said, use the search function as there are already some good threads around here on D12 mics repair, with guides, tips and success stories

 

[s2udio]

L091c​

Glad to hear it, for those that do not have a destroyed membrane and coil it works fine.
My 2 D12's are still great as well.
I recall someone was going to produce a replacement, cant remember who though ?,
And if they ever did..........?
Lot of water under the bridge since then, also seems a lot more aggresive unconstructive comments around here Since those old forum days, Oh Well ?

 

[beatnik]

If the coil is open internally there is no chance it can be fixed.

Most of the times the coil wire is broken at the ends, if the remaining wire is long enough it can be soldered again. If it's too short it should be possible to solder an extension but you need a very thin wire and a microscope or some very good magnifier lens.

For a while I was interested in making these, I found some companies in the UK interested in making the air wound coil but I did not go ahead looking for someone to make the membranes and putting the two parts together.
I think trying to get the thing done in the western world would not make sense cost wise, perhaps the only viable option is finding a dynamic microphone factory in Asia and have them reverse engineer the whole thing.

 

[Whoops]

Most of the times the coil wire is broken at the ends, if the remaining wire is long enough it can be soldered again. If it's too short it should be possible to solder an extension but you need a very thin wire and a microscope or some very good magnifier lens.

How to you solder those thin wires?
I tried in the past to resolder dynamic mics coil wires, but the wire is so thin that it completely melts as soon as I touch it with the soldering iron, just vanishes.
Whats the trick here?

Thanks

For a while I was interested in making these, I found some companies in the UK interested in making the air wound coil but I did not go ahead looking for someone to make the membranes and putting the two parts together.
I think trying to get the thing done in the western world would not make sense cost wise, perhaps the only viable option is finding a dynamic microphone factory in Asia and have them reverse engineer the whole thing.

Yes I think having the membrane done in Asia would be the best solution.
Imagine how may broken D12 mic and related family could be fixed if there was a replacement diaphragm available.
Probably all of the D12 mics in the world could be fixed then

 

[camshash]

Colepicksvintage.com fixes microphones, I know hes done a bunch of D12's.

 

[Timjag]

Esa Tervala, panman in this forum is the most experienced person around in fixing D12 mics (and related). Probably one of the most experienced people in the World if not actually the most experienced.

Like he said, use the search function as there are already some good threads around here on D12 mics repair, with guides, tips and success stories

Whoops,

yes Esa is the absolute man for D12/19/20 repairs - he’s a genius, I didn’t share his name publicly because I wasn’t sure whether he wants to be inundated with requests.

he’s fixed three of my mics, one non working since the 1980s! They all sound wonderful, just don’t tell him you’re going to stick it inside a kick drum!

 

[Whoops]

Whoops,

yes Esa is the absolute man for D12/19/20 repairs - he’s a genius, I didn’t share his name publicly because I wasn’t sure whether he wants to be inundated with requests.

Im sorry if sharing the name is a problem, it was in the hope that more work comes to him and not problems.
And also to let people know who should they contact for D12 repairs.

if that’s a problem I will edit my posts and ask other people to edit theirs so that the name is not shared

I didn’t know who was experienced on this repairs in the past and unfortunately sent my mics for repair to a member here that said he could fix it and in the end he didn’t have the experience or expertise to fix this mics and actually make the situation even worse.

 

[David König]

Hi, I am repairing D12s or D19s (and many other old dynamic mics) for decades. If you have a faulty mic for sale or swap I am interested.