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Author Topic: Early U67's With Titanium Diaphragms?  (Read 4356 times)

J. Mike Perkins

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Early U67's With Titanium Diaphragms?
« on: March 21, 2013, 01:49:13 AM »

The Seller of U67 #841 on ebay claims early U67's, like the one being sold, had titanium diaphragms with helium gas in the middle.  Has anyone ever heard this before?  This does look like a legitimate sale given the large number of photos and very detailed description of this mic, but I have never heard anything about a titanium capsule in a U67.  Legend?

http://www.ebay.com/itm/NEUMANN-U-67-TUBE-CONDENSER-MICROPHONE-841W-POWER-SUPP-CABLE-SUSPENSION-FINE-/321093015471?pt=US_Pro_Audio_Microphones&hash=item4ac2a297af

From the descrption "This U 67 is serial #841.  Capsule # is 844.  These early versions used stretch titanium diaphragms with helium gas in the middle.  This gave them an incredibly transparent high frequency response and transients.  This info was given to me years ago when I first acquired this microphone." 
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Kai

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Re: Seller claims early U67's had stretch titanium diaphragms?
« Reply #1 on: March 21, 2013, 10:14:24 AM »

The Seller of U67 #841 on ebay claims early U67's, like the one being sold, had titanium diaphragms with helium gas in the middle.
As can be seen in the photos the mic has a normal plastic (mylar ?) foil diaphrag.
You can see the holes in the backplate through it, something that is impossible with a metal (titan) foil of any usable thickness.

Anyway the construction of these capsules requires a non-metallic isolation ring at the edge of the diaphrag, which can be seen in his pictures too.
A full face metal diaphrag like on the KM53/54/56 wouldn't work.

The sputtering looks golden in his pics, titan has a matte silver colour.
A titan sputtering would have been lost by oxidation over the years anyway.
Even gold has it's problems after 40 years.

The helium filling - if it ever existed - would have disappeared through the years too.
Helium is a very thin gas, that can easily escape.
You would need to store the mic in a helium filled box to preserve it.
If some of the helium would enter the tube you can make it a nice glowing light bulb then  ;D

I suspect the whole thing is a myth.
At least the seller does not present any evidence, but the contrary.
Nevertheless the mic looks great.

Kind regards
Kai

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klaus

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Re: Seller claims early U67's had stretch titanium diaphragms?
« Reply #2 on: March 21, 2013, 12:23:17 PM »

Maybe the seller inhaled Helium right before he wrote the copy.

To add one aspect to Kai's thorough de-mystification of the claim:
Any gas, including good old air, can freely move in and out of the capsule cavity and its inside passages through a pressure equalization slot Neumann engineered into the center of the capsule, to keep atmospheric pressure between outside and inside the capsule always the same.


P.S.: after contacting the seller and pointing out that he was mistaken, he responded that he would remove the erroneous claims.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

J.J. Blair

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Re: Early U67's With Titanium Diaphragms?
« Reply #3 on: March 27, 2013, 04:15:08 PM »

Helium is probably a lousy dielectric, anyway, and all the vocals would sound like Alvin and the Chipmunks, I'm sure.

 :o
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Jim Williams

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Re: Early U67's With Titanium Diaphragms?
« Reply #4 on: March 29, 2013, 12:14:25 PM »

Nitrogen is best. It's rather inert. It has "air weight". It works very well in my 35" off road mud terrain Jeep tires.

You don't even need to capture it, it's 80% of the air you breath. It's that nagging 21% of oxygen that rots everything, including bare rock.

Unfortunatly, you need that to breath.
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GYMusic

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Re: Early U67's With Titanium Diaphragms?
« Reply #5 on: April 02, 2013, 09:08:30 PM »

I love the inhabitants of this place.....
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