AKG D12 repair attempt...

[cyrano]

You are accusing others of misinformation, while at the same time you are exposing theories without any supporting evidence whatsoever.

As always, people can believe whatever they want. Some will repair on their own, some will go to the self proclaimed gurus.

I really resent posts like these. You obviously know nothing about PanMan. He's repaired several D12s for me. Even one that drove me crazy.

You probably won't believe me, but PanMan isn't a self-proclaimed guru. He is THE reference in D12 repair, also because he still has some original parts. Afaict, nobody else has parts, even remanufactured ones, let alone original parts.

 

[beatnik]

Afaict, nobody else has parts, even remanufactured ones, let alone original parts.

I can guarantee you, you really can't tell.
Myself have a box full of all kind of D-series parts including NOS diaphragms.
I am sure many other people have you should avoid making this kind of short sighted assumptions.
How can we expect to believe your opinion as panman being THE one and only, with this kind of narrow view ?

This is a diy forum so expect people to tinker and discuss self made repairs.
You are welcome to send your microphones to panman if you can't fix them yourself.
But think for a moment, wouldn't it be crazy if in the gssl compressor thread people ask information how to build one, and they get told to buy from SSL because that's the only way to get it right ?
For some reason this thread has started as a diy tutorial kind of thing, and degenerated into a vibe of don't even try, only this guy can do it.
Maybe I was wrong panman is not self proclaimed guru, it's you guys that have elected him, and you want to make your limited experience universal law.

 

[cyrano]

FWIW, I knew PanMan before I joined this forum. Not personally, I've never met him. I've sent out D12s to other repair services and had nothing but bad experiences with these.

There are two kinds of mic I'll never try to repair myself, that's the D12 and Sennheiser MKHs. Probably Neumann too, but these haven't crossed my path.

 

[raketenmann]

Pls. people, I think we should no longer take this post in this direction - noone will benefit from it. I hoped we stopped this before. Of course everyone is very welcome to try to repair anykind of microphone he/she want. Some might get lucky, some might not. I still insist: getting ANY D12 right could be a difficult task for some of us - and for some of us it won't. That's totally cool. And the ones that can't (me, @cyrano and a lot of other people) rely on @panman who really can fix ANY D12 and bring it into specs. As long as we're all happy in the end its cool! And of course: having NOS spare diaphragms would be a huge advantage. AFAIK panman doesn't have NOS diaphragms. He takes a heat air gun to bring them back to the correct shape. And this seems to me as a crazy piece of art.

So please let's get back to topic: to share ALL the best ideas to work on these mics to get them back to live!

 

[raketenmann]

I can guarantee you, you really can't tell.
Myself have a box full of all kind of D-series parts including NOS diaphragms.

BTW: Do you sell NOS diaphragms?

 

[Whoops]

How can we expect to believe your opinion as panman being THE one and only, with this kind of narrow view ?

You are a very disrespectful person.

Panman is the most experienced person and most successful person in the fixing D12 family of mics.

Like other people have said, Cyrano for example, I also tried all the other services available in the World for this kind of job and all of them failed.
While with Panman I'm already in my fifth very successful microphone repair.

This is a diy forum so expect people to tinker and discuss self made repairs.

You keep repeating yourself in subjects that were already discussed before.
For sure this is a DIY forum but people need to know that repariring dynamic capsules, diaphragms and coils work is not a task for the average DIYer, it’s very difficult to do and in the case of the D12 (and similar) you can damage a valuable mic for good while trying to do something that you have no experience whatsoever.
The coil wire melts easily, and the coil is easily damaged.
The diaphragm can be ripped or poked, or perforated easily also.
There’s a lot of sensitive parts in this work, so easy to destroy the capsule for good.

wouldn't it be crazy if in the gssl compressor thread people ask information how to build one, and they get told to buy from SSL because that's the only way to get it right ?

That’s complete nonsense.
The GSSL project is a relatively easy project to do.
Even if you damage any part while building it all the parts are readily available and easy to swap for a good one. There’s almost no risk involved

With a D12 capsule is far from it, damage the coil or the diaphragm and you’re gone.

GSSL - easy to do , no risk
D12 capsule repair - difficult to repair, a big risk involved

Making that ridiculous comparison and giving such public bad advice makes me really be sure that you don’t know anything that you’re talking about, if you had any experience whatsoever with the work involved in properly repair a D12 microphone you wouldn't for sure write such a comment.

For some reason this thread has started as a diy tutorial kind of thing, and degenerated into a vibe of don't even try, only this guy can do it.

You were the one that made it that way, people just advised Panman repair services, and you just started your own rant attacking him, when he was polite and could provide useful info and insights.
You could learn something here, but you decided not to and start arguments against a gentleman.

Maybe I was wrong panman is not self proclaimed guru, it's you guys that have elected him, and you want to make your limited experience universal law.

No one self proclaimed anything at all. That's your invention.
My best advice to anyone reading this thread in the present or in the future is that I highly recommend Panman services for D12 microphones repair,
and I also advise people to not trust anything you say on this matter.

I feel sorry for any person that might send you their D12 microphone

 

[JohnRoberts]

can you guys behave.... this thread was reported..

I don't know what it is about microphones?

JR

 

[beatnik]

You are a very disrespectful person.

Panman is the most experienced person and most successful person in the fixing D12 family of mics.

Like other people have said, Cyrano for example, I also tried all the other services available in the World for this kind of job and all of them failed.
While with Panman I'm already in my fifth very successful microphone repair.

Am I disrespectful just because I am telling Cyrano he's wrong to assume nobody other than panman has D-series parts ?
This was a complete nonsense idea from Cyrano but you even go further, you even claim you have seen all the World.
These absurd propositions very much resume there is no substance behind your theories.
You are just extrapolating your personal experience and wanting the rest to believe the Earth is flat.

Whoops you are the one openly disrespecting me - while at the same time wrongly accusing me of being disrespectful just because I challenged absurd ideas.
This thread has been a resource for people wanting to repair their own microphones, it would be a shame if it gets locked because you want to come here and insult people and go on these personal attacks just because your very personal point of view is challenged.
Don't be so full of yourself, let the people who can do (or even just try with all the risks involved) and the rest are welcome to go to panman or whoever they want.

 

[David König]

If you have faulty D12 based mic (or generally ANY old vintage mic) you may sell it to me for reasonable price and I will fix it myself. Problem solved!

 

[tonedude]

I got this for free and after a cleanup it actually works great, nice balanced sound, good bottom end and with nice mids...

But I thought that I would look into the alignment procedure if it eventually breaks in the future. No, I'm not going to fix it before its not working...

But unfortunately it seems that all the links to the fix with photos is dead, someone even removed one of the backups from the wayback archive.... why?

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

... that link is now a dead end.

 

[cyrano]

The best things in life are free!

Enjoy!

 

[el-jon]

I recently bought an AKG d12E which makes a rattle sound when I turn it a certain way. Upon investigation a tiny non-metallic washer fell out (I'm guessing from the capsule housing), but theres still something loose inside. Doesnt seem to affect normal recording operation, but I would like to open it up and get it out as a precaution. So if anyone could provide the missing photos or similar, I would be really grateful!

 

[systemtruck]

I recently bought an AKG d12E which makes a rattle sound when I turn it a certain way. Upon investigation a tiny non-metallic washer fell out (I'm guessing from the capsule housing), but theres still something loose inside. Doesnt seem to affect normal recording operation, but I would like to open it up and get it out as a precaution. So if anyone could provide the missing photos or similar, I would be really grateful!

I probably took some pics of when I repaired mine. I’ll take a look and post here in a day or two.

 

[systemtruck]

Actually here they are. Basically to just open the thing, you have to at least unscrew those four screws under the black plastic base ( and maybe there are one or two more screws up top ) and then carefully pry apart the two screen halves like you’re opening a sandwich. I have two of these mics.. on one those screws were easy, on the other those screws were caked in with some kind of old glue so that was tough.

Hopefully you literally just have something rattling around that can be removed. It may be a washer for a screw for the unit though. I recall there being some unusually shaped and small sized washers. You’d want to just figure out where it goes.

My repair was far far more difficult than that. It was a diaphragm mounting repair. Basically the larger diaphragm was misaligned and probably also had some dust behind it. I believe I removed the diaphragm and reseated it using some thin shims just made of paper and used some super glue to seal those tiny shims in place. The recorded sound was horrifically distorted. There was nothing physically audible shaking around. So it seems like a different situation.

 

[el-jon]

Thank you for taking the time. Looks good!

I actually did get the grille off, just like in your pictures. My apologies for not explaining more precisely! The small washer (or shim) I mentioned, I believe came from the gap in the capsule. And I suspect the loose object (whatever it is) is trapped inside. Everything looks normal and fairly clean, nothing seems to be missing.

I wonder if there is a way to open up the capsule without disturbing the position of the diaphragm, as the mic already has good low end and sounds great. Definetly a different situation (at least for now). Was the repair a success?

Btw, if I provoke movement while recording, it makes a tiny sound that resembles the flick of a switch. So there is definetly contact where there shouldn't.
Here is a couple of photos for anyone interested. Stickers say "R3" and "67" (Revision 3, 1967 perhaps?).

 

[systemtruck]

“”Btw, if I provoke movement while recording, it makes a tiny sound that resembles the flick of a switch. So there is definetly contact where there shouldn't.””

This sure sounds like the classic symptom of dirt and / or dried up very small old pieces of material floating around inside or outside the diaphragm. I had to address this too I think. Can’t quite recall.

*** Please take this all with a grain of salt. I am NOT a microphone tech. Your mic capsule and coil connections are highly sensitive and are not replaceable. If you damage these things, that’s the end of this mic completely. ***

I don’t know a lot about microphones but I learned, from this one, that this happens with some old mics. I also can’t remember the details about the microscopic coil wires that are attached to the side of the capsule diaphragm somewhere. In my opinion those are more likely to damage than the capsule because they’re so easy to not notice. Anyways I’m saying that first so that you know the caution required. But basically I believe that ultra careful disassembly and inspection and *somehow* cleaning or just dislodging is all that you need here. The difference between mine and yours was that mine also required an alignment because it wasn’t seated well at all, and things were vibrating badly. Sound was working but heavily distorted. I spent a couple hours aligning it with the sine wave fed back into mic at pretty low level and listening closely for the capsule vibrating and adjusting that out. (I never knew what exactly was causing the vibration but alignment and light dust removal both aided in fixing it.) This is the standard method I suppose. It’s kind of mind blowingly simple in concept. Who knew.. mics can make sound like a tiny speaker ! Anyways seems like you don’t need this at the moment, and it would be a shame for you to have to disrupt your good alignment of the capsule in order to get some loose crud piece out, but you should be prepared for that to be necessary. Maybe you can just remove the capsule cover itself first since those contain dust. Then connect the mic and move it by hand and try to get it to do that switching sound. If it’s gone, then your issue is not behind the capsule which makes this much easier. But if it’s not gone, your issue is probably dust behind the capsule which I think means you need to access behind it. But maybe only slightly. I say slightly because I can’t remember how far away / off you can take the capsule. The coil wires may greatly restrict removing it. It may be that you just unmount the screws and very very very carefully make a gap between capsule frame and main section, and carefully encourage some particles back there to shift or fall out from the small opening crack.

But again, please check other sources. This is the general idea though. I’d have to take apart one of my mics to confirm and I’m not willing to do that since things are all in a good spot.

These D12E’s are crusty mics. There is a lot of aged cushioning / padding / filtering material in these that has gone bad and flaked to pieces. I’m 99% certain that this old material is the main cause of issues.

 

[s2udio]

Hi Folks
See this thread has popped up again (I was the original poster of the teardown repair)
I can still edit the original posts if I can find the original pics (I am sure I have them archived somewhere !)
Give me a few days and will see what I can rustle up !
The D12 I repaired is still in use on my Kick to this day !
For any sucessful repair on this mic you will have to strip it down no if or buts.
The coil and diaphram condition must be verified, you can only do this by removing the top cover CAREFULLY!!
The coil gap gets full of oxidated crud, it has to be cleaned out completely.
A Start would be an ohms check, if aprox 200-300 ohms you are in with a chance.

 

[panman]

Take the bass-chamber loose first and find out, if the rattle is there. I have seen it a couple of times, that a plastic piece is inside. It is better to rule it out before removing the reflector(top cover), because that is not easy to do without destroying the diaphragm. Once the reflector is out, beware, that the strong magnet pulls only too easily the screwdriver on it and there`s your diaphragm destroyed. Only too often the reflector is not coming off without removing the retaining ring and that`s another story again.

 

[OneRoomStudio]

I just wanted to chime in with a few observations after repairing half a dozen of these:

1) I had one with something rattling inside. I took it completely apart, only to find that the rattle was coming from the plastic “yoke” part (where it says “Made in Austria, 200 ohms”). This part is glued shut, and I didn’t want to risk breaking the old brittle plastic taking it apart. So…if you shake the mic, it rattles a little, but it doesn’t cause problems in use. My theory is that one of the square nuts that retain the grill screws had somehow become lodged inside (2 were missing).

2) Speaking of the square nuts and screws, you can buy replacements from Accu. The nuts are 4mmx4mmx1.6mm M2.

3) If you’re having a hard time getting the diaphragm to sing at lower frequencies after cleaning the magnet gap, don’t forget to try rearranging the shims. Some of these mics need three below the diaphragm and one above because they have been compressed over the years.

 

[Whoops]

Thank you for taking the time. Looks good!

I actually did get the grille off, just like in your pictures. My apologies for not explaining more precisely! The small washer (or shim) I mentioned, I believe came from the gap in the capsule. And I suspect the loose object (whatever it is) is trapped inside. Everything looks normal and fairly clean, nothing seems to be missing.

Maybe Panman knows what washer is that and were it might have come from,
he is the right person to ask