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Author Topic: Sm-69 cable replacement  (Read 734 times)

afterlifestudios

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Sm-69 cable replacement
« on: July 18, 2020, 03:47:16 pm »

Any recommendations on suitable wire for replacing my sm69 FET cable.  I have connectors but the existing cable is problematic.  (Crackles and noise when moving etc.)
Would like to replace.
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Kai

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Re: Sm-69 cable replacement
« Reply #1 on: July 22, 2020, 06:21:05 am »

If that crackling happens on one part only you might be able to cut it and remount the plug.

During this you can remove the sleeve of the cut away part and examine if the screen is brittle or maybe even in parts already.
This is what can happen with very old cables sometimes.
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klaus

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Re: Sm-69 cable replacement
« Reply #2 on: November 21, 2020, 04:54:51 pm »

When you experience moving noise, it is almost always related to defective or incorrect terminations. 

And here, the same devil shows up as the one that prevents quiet operation on other types of mic cables: improper ground/shield terminations, where

* ground and shield are NOT terminated at the ground pins of the connectors on both sides, AND
* the shield is not terminated directly to ground on both sides AND
* ground and shield are not terminated correctly to the connector housings on both sides

If even one of these steps was omitted, you can get cable noise and other gremlins like RF and hum.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

David Satz

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Re: Sm-69 cable replacement
« Reply #3 on: November 22, 2020, 10:17:12 am »

I can empathize with the original poster. I owned an SM 69fet in the early 1970s and tried to use it for live concert recording. The cables just didn't seem to be made for that type of application; unrolling them and rolling them back up several times a week seemed to be too much for them, no matter how careful I tried to be. They spent nearly as much time in Gotham Audio's service department as they did in actual use, and I'm not exaggerating by much when I say that; I think I nearly drove poor Joe Leung crazy.

It wasn't a question of shielding and grounding, but of outright broken connections. I had to buy extra cables (each of which cost nearly as much as a good microphone) to serve as backups, bring them along to every recording (they're heavy!), and allow extra setup time, because I simply never knew whether they would work or not.

In a fixed installation I can see a role for this type of microphone, but not for the type of portable on-location recording that I've generally done, with a complete setup and teardown every time. By comparison the USM 69 isn't as flexible in terms of pattern selection--with the SM 69fet I often found myself preferring the "in-between" patterns that have no official names. But if you like the sound of this microphone design in general, and coincident stereo miking is what you need to do, it's a trade-off to consider, since four-conductor shielded cable is entirely manageable.

--best regards
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klaus

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Re: Sm-69 cable replacement
« Reply #4 on: November 22, 2020, 01:08:25 pm »

Here is another twist: Neumann changed cable suppliers for its stereo mics at one point. They never disclosed whether Gotham, Switzerland, which bought microphone cable technology and machinery from Dörfler Kabelwerk in Austria, the original supplier was still the source.
Read moer here: http://www.gothamaudiousa.com/history1.htm
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Klaus Heyne
German Masterworks®
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afterlifestudios

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Re: Sm-69 cable replacement
« Reply #5 on: November 22, 2020, 02:55:08 pm »

Thanks gentlemen.  I've followed the proper grounding and terminations at the connectors.  I've tried isolating sections of the cable for testing moving noise, but it's very hard to isolate.  This is why I ask if there is a newer, reliable 12 conductor that is know to be suitable as a replacement cable? 
(Fet version here by the way, so some of the conductors are redundant.)
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klaus

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Re: Sm-69 cable replacement
« Reply #6 on: November 22, 2020, 04:31:56 pm »

The only cable I would use is the Neumann 11-conductor + shield type. Others. like Mogami, use a variation of  the classic snake: several XLR-3 pairs in one jacket.
On and off through time you can order complete SM69 cables, and sometimes just the material, from Sennheiser in Connecticut, but Neumann in Berlin has these still available, last time I checked (2019).
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Klaus Heyne
German Masterworks®
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afterlifestudios

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Re: Sm-69 cable replacement
« Reply #7 on: November 25, 2020, 01:49:18 am »

Thanks Klaus. Is this the stuff?

https://en-de.neumann.com/k-11

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klaus

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Re: Sm-69 cable replacement
« Reply #8 on: November 25, 2020, 03:23:06 am »

Yes. And use the thicker conductors for ground and tube heaters.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com
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