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[Mozart]

Hi,

I'm enjoying reading posts here, not much of a poster, but I need help.

I have an SM2 microphone, with the top back capsule shot 🤦‍♂️ and noise. Is there a reliable honest service where I can send the mic for a capsule repair/re-skin and check up the whole mic?

Thank You!!!


Kosta

[klaus]

I read somewhere that Mozart died centuries ago, so you cannot possibly be Mozart.
Please fill in your real name,  in order to continue posting! The Ground Rules (https://repforums.prosoundweb.com/index.php/topic,989.0.html) make it so.
Thanks,
KH

[Mozart]

I'm aware of that, real Mozart died centuries ago.
It was my nick name that my piano teacher in 2nd grade gave it to me, as I was playing all the pieces by the ear. Stayed thru the years,... That is my story about my nickname.

Sorry, I just updated my personal info, as it did not show up when I was making my account.

Kosta

[klaus]

Excellent, and thank you!
There are not many people left in the world (big word, I know) who have a deep knowledge of and history with Neumann's nickel-capsule stereo mics.
SM2, SM23 are fragile constructions, unique designs, with major parts that have long been obsolete.

Siegfried Thiersch who used to be in charge of making nickel capsules at Microtech Gefell, and who later went independent as a capsule reskinner, had a good grip on Neumann's SD nickel capsules and did a decent job re-diaphragming them with nickel material.  He also was the only one in that specific field. The results, while not identical with Neumann's were quite passable.

But Siegfried must now be in his late 70s or older, and to my knowledge no longer does that type of work. Whether there is a successor with his nickel skills at his company I do not know. I also do not currently know of any other source for repairing nickel diaphragms.

[Mozart]

Thank You!

I contacted them, lets see what they say...

In the mean time if anybody else has any info, will be really appreciated.

Best to All!

Kosta

[afterlifestudios]

There is a forum member here "Panman" who helped me with my km56 capsule.  He's in Switzerland.  Try sending him a direct message through the forum?

[Mozart]

Thank you!

[Mozart]

After contacting Siegfried Thiersch, he finally was accepting capsules for repair, and my SM2 Capsule Basket is received by him.

My dilemma:

Only top back capsule was damaged. Front worked fine. What should I do, replace all 4 sides for matching or replace only the damaged side? (not sure if he can do only that). or both sides of the top (damaged back) capsule.

Another question would be about the internal wires in the head basket, the ones inside the plastic. They seem to rigid, so from the turning the top capsule position, some solder connections got  snapped.

Isn't today available some other, more flexible, type of wire for the given position?

Thank You for all the advices.

[klaus]

Advice #1:
By all means, try to preserve and retain the three sides that are not damaged: Thiersch's re-diaphragming will inevitably change the timbre of the capsule, but its sound for front-side pickup will stay pretty much the same when only one rear diaphragm is replaced.
And as the two well-working sides facing the front are original, don't chance a sonic mismatch, if you can.

Advice #2: Try to resolder the broken connection in the center wire. re-wiring will be a pain.

[Mozart]

Thank You for your advice!!
I just sent email asking to preserve the originality of the microphone as much as possible.

Best Regards!

[klaus]

...and try to be specific:
It's easier for Thiersch to start with two fresh diaphragms rather than saving the original one that is still good; make it clear that you want him save the front side if at all possible.

[Mozart]

Thank You Klaus! I think I was!

[Mozart]

This is the reply I got, It might help someone:

"In my opinion, Neumann did not provide for repairs for transducers, but only for the complete replacement. SM2 has 2 double transducers. We try the repair anyway.
Problems are caused by the removal of dust.
Dust is produced when the old membrane is removed, when the adhesive surface is roughened and the backplate is smoothed.
When blowing out the dust, some dust inside can flow to the other opposite (single) transducer. However, if the membrane is mounted there, the dust cannot be removed there.
If you take out the brackets, you can separate the converters from each other. Then you can blow out the transducer individually with the diaphragm removed, but you have to re-clamp with new non-original brackets. It has happened that the backplate disintegrates and has to be re-glued before the membrane can be glued.
Best regards
Siegfried?"

Scratching my head now..

Kosta

[klaus]

What he said is correct. To explain further:
On SM2 and KM56 the two capsule halves/front and back-are actually somewhat autonomous and don't share the same backplate. Though the two halves share acoustic space their backplates are tied together with three flat metal clamps, they are self-contained.

In order to save the good side intact, the metal clamps holding the two backplates together have to be opened up and removed, the two backplates separated, the defective side re-diaphragmed, and then reassembled. 

As he stated, Thiersch usually does not separate the backplate assembly when he reskins, and what you ask him is a bit more involved, but that is by no means beyond his skills (I have done that repeatedly, to match the best two of four capsule sides  in a stereo head as front sides).

[soapfoot]

Is Mr. Thiersch still doing all the repairs himself at 80 years old? Or is it possible he's got some younger apprentices and only does the more complex repairs?

[Mozart]

What he said is correct. To explain further:
On SM2 and KM56 the two capsule halves/front and back-are actually somewhat autonomous and don't share the same backplate. Though the two halves share acoustic space their backplates are tied together with three flat metal clamps, they are self-contained.

In order to save the good side intact, the metal clamps holding the two backplates together have to be opened up and removed, the two backplates separated, the defective side re-diaphragmed, and then reassembled. 

As he stated, Thiersch usually does not separate the backplate assembly when he reskins, and what you ask him is a bit more involved, but that is by no means beyond his skills (I have done that repeatedly, to match the best two of four capsule sides  in a stereo head as front sides).

Thank You for clearing it up for me, I was not aware.
Best!

[Mozart]

Is Mr. Thiersch still doing all the repairs himself at 80 years old? Or is it possible he's got some younger apprentices and only does the more complex repairs?

No Idea.

[afterlifestudios]

No Idea.

Since you are in communications with them currently, perhaps you could ask them on behalf of us curious forum members?  No big deal, but interested to know...

[Mozart]

I don't know if he is still doing the repairs.

I'm confused and don't know what to do. Any advise will be appreciated. Here is the response from Mr.Siegfried:

"The SM2 capsule is not suitable for repair. Trying to do it anyway sometimes fails. A problem of several I give with the reskin with Ni membrane. In this case, the laterally led connection must be bent back from the transducer in order to be able to attach the new membrane. This can break, but this must not be for the upper transducer system. For such cases, I replace the transducers of the systems, unless both have defective connections
When using Mylar film, you can probably leave the connections, one risk less. Mr. Peter Drefahl uses Mylar film. In your case, it would be cheaper to produce a membrane with this film.
Sincerely,
Siegfried
Hallo Kostadin
 
Die Kapsel SM2 ist für eine Reparatur nicht geeignet. Versuche es trotzdem zu tun scheitern manchmal. Ein Problem von mehren ergibt ich bei dem reskin mit Ni-Membran. Hierbei muss der seitlich herausgeführte Anschluss aus dem Transducer zurück gebogen werden um die neue Membran aufsetzen zu können. Dieser kann brechen, das aber für das obere Transducer-System nicht sein darf. Für solche Fälle tausche ich die Transducer der Systeme, sofern nicht beide defekte Anschlüsse haben.
 
Bei Verwendung von Mylar-Folie kann man wahrscheinlich die Anschlüsse belassen, ein Risiko weniger. Herr Peter Drefahl verwendet Mylar-Folie. Es wäre in Ihrem Fall günstiger eine Membran mit dieser Folie herzustellen.
Mit freundlichem Gruß
Siegfried"

Thank You!

Kosta

[Mozart]

Since you are in communications with them currently, perhaps you could ask them on behalf of us curious forum members?  No big deal, but interested to know...

\


I will in my next email.

[klaus]

The bending back of the lead out wire (so teh capsule clears upon removal from the mount) has not been an issue for me in the past.

If you intend to reskin with Mylar you may as well save your money as sell the mic as is: No one wants that sound out of an SM2, and no one will pay you SM2 prices after you replace the core, sound-shaping component with one that was never intended to be used in that mic.

[Mozart]

Here is the last Response from Mr. Siegfried:


"With the exception of me and Mr. Drefahl, such capsules were never repaired but only replaced. Perhaps Mr. Drefahl can only change one membrane. Presumably, he can stick the PE membrane on without bending back the bent connections. Thus, the connections can not break. Membrane can be renewed several times.
For the upper system, the connection strand cannot be soldered back on after a break.
Now we are overloaded and have waiting time of 4 months. My age is now very high. Except me, no one makes SM2 with Ni. The Ni service will be discontinued. I would advise you to inform Mr Drefahl of your matter and to ask his opinion.
Sincerely,
Siegfried"


Here are the pictures from my capsule:

Any Advise will be appreciated!

Thank You!

[klaus]

Thiersch, it seems, no longer has any interest or capacity to replace nickel diaphragms.

But his alternative suggestion to have the defective nickel skin replaced with a polyester membrane is not viable, in my experience, because it alters the sound of the capsule dramatically. Listen to a KM86 and you know the direction.

I would suggest to find another owner of an SM2 in the similar position as yours (though it may take a while), buy the head from that person and transplant one capsule- either from his head to yours or vice versa, whichever sample appears to be in better shape.