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R/E/P => R/E/P Archives => Klaus Heyne's Mic Lab => Topic started by: Fibes on April 21, 2004, 05:35:43 PM

Title: Neumann M269c.
Post by: Fibes on April 21, 2004, 05:35:43 PM
First of all i would like to welcome Klaus and his knowledge to this forum, i hope to exploit it for all it's worth. It's an honor to be a moderator with a crew like y'all.

The M269c- My absolute favorite condenser mic, the german broadcast version of the U67. Absolute magic in my opinion.

I have a problem--- My Tuchel connector is loose and the mic becomes intermittent when hung upside down. Is this an easy fix? Who should i send it to get repaired and tweaked? Klaus?

I fear that this will require a retooling, please tell me it's an inexpensive fix, it's been a week of gear meltdowns...

Thanks,
Title: Re: Neumann M269c.
Post by: Fletcher on April 21, 2004, 08:11:16 PM
I'm not Klaus... but I'm going to take a whack at it.  If I'm not mistaken, the M-269c employed the same connector on the microphone as the U-67.  That part was available from Neumann/USA last time I checked [which was a while ago], as are the cable mount connectors for U-67's [the stand mount connector housing is rather difficult to find, but the inside is the same... IIRC].
Title: Re: Neumann M269c.
Post by: Klaus Heyne on April 21, 2004, 11:09:46 PM
Sorry Fletcher, no Cohiba this time.
The connector in the M269 is very common, still being manufactured by Binder in Italy and identical with all other 200-series Neumann broadcast connectors EXCEPT the U67 connector, whose pin pattern was offset by 10 degrees (on purpose, so that you don't wack 210 volts into your AC701-equipped mics)

Regarding the "loose" connection: I may not understand which part of the set up is loose in your system, so let's be really specific:

1. The male connector in the bottom of the mic is loose on purpose, to allow it to adjust its position with slightly off-set cable females which, because they are rigidly embedded in the connector housing, could otherwise bend the fragile connector shoes. So that part is OK, and will not cause any intermittent mic operation. I also must say that I have very rarely encountered bad plating on Tuchel connectors which would cause bad contact.

2. You need to look really carefully inside of the cable female  and inspect:
a. the integrity of the black plastic insert (broken off portions? Missing friction washer? Can the connector insert be twisted inside the metal housing?)
b. missing, broken or intermittent solder connections between cable conductors and connector pins

In either case, at worst you are looking at  some sweat equity and/or a new connector insert (maybe $50.-) to get you back on the road.

To whom should you send this mic? First, analyze and trouble shoot, then make the decision, how sophisticated of a mechanic you will need. This is not rocket science; a technician with a good soldering resume is going to be fine.

Kind regards,



Title: Re: Neumann M269c.
Post by: Fruition Music on April 22, 2004, 12:00:18 AM
Kevin,
I found a similar issue with my M269c after wiring up the N52 (Klaus thanks for the pinout you emailed me back then), I started with the original gray Neumann cable and connector but ended up replacing it with new Gotham Audio cable. Not only did I find the female connector corroded, it somehow wasn't even assembled correctly which made it difficult to spin and screw in.
Took some time and care, cleaned the connector and all the partsc, adjusted the 4v in the N52 to the AC701 and its been wonderful ever since. I will add that you may not want to operate the 269c or any mic with the AC701 if something is intermittent,...stray voltages spikes to 701's can possibly damage them I've been told.

Klaus its great to have you here in this forum, thank you for sharing your valuable time and knowledge.
Title: Re: Neumann M269c.
Post by: Fibes on April 22, 2004, 09:46:07 AM
It seems to be the insert or something related. Something I should have added in my original post is that i'd like someone to give it and the power supply a once over before I put it back into action. The mic is that important to me.

I would love to hear what y'all think makes this mic so magical, i think i know but to be honest, I'm no scientist.
Title: Re: Neumann M269c.
Post by: malice on April 22, 2004, 11:23:41 AM
Hi Klaus,

Great idea to start this forum !

I gotta chime in this discussion.

I agree with fibe here, this mike has a magic on his own. I think it's probably my favorite female vocal microphone of all time.

I noticed that it is not like a 67 with a slightly different freq response.

It react dynamicaly in a noticable different way (Am I close Fibes ?) ...

I'm trying to buy another one btw.

I would love to hear Klaus opinion

best

malice
Title: Re: Neumann M269c.
Post by: Klaus Heyne on April 22, 2004, 12:52:43 PM
Denis/malice

I have heard other people as well making a distinction in the sound of two mics that are , at least in theory, very closely related: The M269 and the U67.

First off, here are the only technical differences between a U67 and an M269 (non 'c' version) mic, contrary to what you might have heard regarding different frequency response components or circuitry:

-The tubes (EF86 vs. AC701)

-The voltage and current going to the tubes (beyond the scope of this forum.)

-The electronic components (resistors) which accomplish  
 that.(same as above.)

Over the years I have repeatedly made the following comparison test, in order to find out what factor that tube difference has on the sound of the mic:

I used two stock, well working units, both with Neumann selected Telefunken tubes, and both working at optimal operating conditions. I then transplanted one of the capsules back and forth, between M269 and U67 amp, so that the considerable influence of each capsule's individual sound was eliminated from the tests by using just one capsule for both mics.

What I found was an ever so slight softening of the dynamics with the M269. No large, fantastic revelations beyond that.

However, if you use the M269c's amp on that test, you will find the same, more noticeable characteristics shared with all cathode biased tube mics- a slendering of the mic's midrange, and a slightly increased transparency in the midrange, at the price of the robustness of the mids.

That's it.
All of these audible differences, by the way, are on a much smaller scale than the differences encountered when comparing two different K67 capsules. I suspect that Denis's wonderful mic's secret is the very capsule he has in that mic, over and above any other distinctions of model or series.

Kind regards,




Title: Re: Neumann M269c.
Post by: malice on April 22, 2004, 01:21:09 PM
Klaus Heyne wrote on Thu, 22 April 2004 18:52

 I suspect that Denis's wonderful mic's secret is the very capsule he has in that mic, over and above any other distinctions of model or series.





Klaus,

thank you for the reply

I might have been very lucky with the one I purchased.
I agree that I've heard some great U67 and some terrible ones ...

So as you say, maybe the difference is not that obvious.

I just noticed that you prefer unanimous posts

So I will comply gladly to the specific requirement of this great new forum

best to you

Denis Moulin aka Malice
Montpellier
France

Title: Re: Neumann M269c.
Post by: Klaus Heyne on April 22, 2004, 01:39:49 PM
[quote title=malice wrote on Thu, 22 April 2004 10:21]
Klaus Heyne wrote on Thu, 22 April 2004 18:52

 
I just noticed that you prefer unanimous posts
So I will comply gladly to the specific requirement of this great new forum

best to you

Denis Moulin aka Malice
Montpellier
France



That's the spirit!
Now we can talk among friends.Thank you and:
Welcome to the inner circle!
Title: Re: Neumann M269c.
Post by: Fruition Music on April 22, 2004, 10:27:52 PM
Ocassionally I see the SM69 stereo tube for sale, its supposed to be the stereo M269c. Klaus, have you or others out there made the comparison in similarities between both mics sonically?

Also does the grill/scrren being different shapes change the sound much? In the late 80's I remember the Stephen Paul Mix mag article tests with the U47, its sonic differences with and without the grill on/off...anyone care to share their findings?
Title: Re: Neumann M269c.
Post by: Mark Lemaire on April 22, 2004, 10:42:24 PM
At one point I tried like mad to buy an SM69 because of one that I loved I used all the time at a certain studio. During this period, I got another SM69 sent to me on approval. Upon firing it up I got the immediate impression that it had 'that SM69 tone" that I loved. A certain sort of 'edge' in the upper mids. Alas, I did not buy that one because the head's pivot mechanism was mechanically screwed up.


I eventually wound up getting a pair of M269s instead (probably a much more versatile solution).  Nevertheless, I did NOT get 'that SM69 tone that I loved" upon firing them up. I got a different sound that I love very much instead. A little less edgy, a little more 'balanced', for want of some better term.

Later, Klaus modded/ optimized the pair. Lovely! Their typical use for me these days is (set to omni) as one of two main pairs for orchestra. The other pair is (2) DPA4003. The Neumanns 'win' perhaps 70% of the time.


Mark Lemaire
Title: Re: Neumann M269c.
Post by: Klaus Heyne on April 23, 2004, 12:30:38 AM
There are some relevant differences in the design of the M269 and the tube SM69: Never underestimate the power of the transformer on the sound! (Have you ever heard a U47 with a Triad trafo? Awful!)

The transformer in the U67/269 is a very beefy affair with lots of iron, fat and complex winding patterns (I'm sure Oliver could add a thought or two here) whereas the SM69's has to be slim enough to fit the narrow housing tube.

That scratchy upper-mid behavior of the SM69 Mark is mentioning is mainly due to the circular head basket with its funny resonances, also it's due to the wide open high end the SM69 amp is run-  remember, the mic was commissioned and designed for distance orchestra pickup, and, to compensate for the air molecule friction over distance (high fre. attenuation) the mic amp's high end was barely attenuated, so that the capsule's natural boost of 6-8dB @10k was left almost undisturbed.

Kind regards,
Title: Re: Neumann M269c.
Post by: Oliver Archut on April 25, 2004, 09:46:41 PM
There are some major differences in those two transformers, the BV12 used in a U67 and M269 is a 49% Nickel core that has 10 times more core cross section than the tiny U17 type used in the SM69. To compensate for the small size they use a different nickel alloy that is more dense. In fact if you use the same type of Nickel for the BV12 and stick it in a M269 the base sound will change dramatically.  

Aside the different alloy the BV12 is a multi section mantel UI core, with a feedback winding for the low cut, etc. where the mini UI in the SM69 is nothing more than a simple mantle x-former, that means just secondary over primary winding, this alone gives the SM69 design a head start.

Best regards,

Oliver
Title: Re: Neumann M269c.
Post by: Klaus Heyne on April 25, 2004, 10:06:31 PM
Oliver Archut wrote on Sun, 25 April 2004 18:46



Aside the different alloy the ( M269/U67 transformer) is a multi section mantel UI core, with a feedback winding for the low cut, etc. where the mini UI in the SM69 is nothing more than a simple mantle x-former, that means just secondary over primary winding, this alone gives the SM69 design a head start. Oliver



Oliver,
Please explain (in VERY SIMPLE terms!) why the transformer construction in the SM69 gives this mic a 'head start' as you call it, when you seemed to praise the beefy construction and winding complexity of the transformer of the U67 early in your post.

Kind regards,
Title: Re: Neumann M269c.
Post by: Oliver Archut on April 25, 2004, 11:32:40 PM
Head room is not everything, the winding technique is about 50% of the sound. The SM69 windings would make a better x-former on the BV12 core....
The feedback winding of the multi layered BV12 sits in-between primary and secondary shielding and creating a degree of phase shift....

Best regards,

Oliver
Title: Re: Neumann M269c.
Post by: David Satz on April 26, 2004, 01:04:29 PM
There's enough difference in the frequency response and voltage gain of the U 67 and M 269 amplifier circuits to make them sound different in a careful direct comparison.
Title: Re: Neumann M269c.
Post by: David Bock on April 26, 2004, 03:20:52 PM
It should also be noted that the absolute broadband headroom of the 269 is lower, but that the peak distortion component on the 67 is far more complex and offensive (you never get anything for free in audio). In addition, the 269 is a self bias as opposedd to the 67's fixed bias amp, again, affecting peak parameters differently.
So really there are some frequency, dynamic, and distorion differences that we can measure and quantify here.
Then of course there's individual capsule aging...
regards,
David Bock
Soundelux Microphones
Title: Re: Neumann M269c.
Post by: Fibes on April 26, 2004, 03:38:56 PM
Excellent thread, I love the M269c and now I ask: Can someone tell me where to send my fritzing little beauty for a once over and repair? Feel free to do it by email or PM if you don't want to go on record here...

David,

Can you send me an O ring or two for my U95 shock mount? Sure I could go to the hardware store and get one but it may not be exactly the same. Or give me a part number or something?
Title: Re: Neumann M269c.
Post by: Klaus Heyne on April 26, 2004, 04:25:24 PM
Dear Davids (Satz, and Bock)
Thanks for chiming in with your thoughtful responses. This quality of posting will be used in distant futures as reference material.

No problem disagreeing with my opinion. I love it!
But now we have to reconcile the following differences:

1. Davis Satz:
There is zero difference in the amp layout, including eq section, and capsule complement, between original 269 (non-c)  and U67.

That would leave the tube. It is probable that an AC 701 (M269 mic) has a different gain than a EF86 (U67 mic)
But a 2dB variation in lows and highs between different, super high premium quality audio tube types??? Never heard of such. So, where would that deviation come from?

I listened to quite a few of of both mics in my life and cannot confirm the measurement differences aurally.

2. Davis Bock:
Of course, the tube's biasing (the way the tube is primed to perform its operation has a bearing on the timbre and frequency response of  the audio circuit the tube serves)
influences the audio considerably. I thought I made that clear in my post.

Therefore the 'c' version of M49, M269, SMx and KM5x mics will always display a different timbre from the earlier non-c versions.
However, I warn the readers not to infer from this statement that later 'c' versions of Neumann (or other manufactures using cathode self biasing) is automatically  preferable. Try installing the 'c' version in a U67 mic, or a U47 mic, and you will find a black hole where there was beauty before.


Let's never forget how we react emotionally to a mic: The midrange texture of the earlier biasing is hard to beat, even as self biasing lowers the noise floor and makes the picture more transparent, something is given up.

Kind regards,
Title: Re: Neumann M269c.
Post by: David Bock on April 26, 2004, 05:10:30 PM
"That would leave the tube. It is probable that an AC 701 (M269 mic) has a different gain than a EF86 (U67 mic)
But a 2dB variation in lows and highs between different, super high premium quality audio tube types??? Never heard of such. So, where would that deviation come from?"
The plate impedance of the AC701 is not identical to that of the EF86, therefore under reflected load condition (actual use) they will not load to the BV12 indentically, causing deviations at thje extreeme ends of the frequency response. This is classic textbook behavior for tube to xfmr loading, see The Radiotron Designer's handbook for a full discussion.
In addition, the gain of the individual tube used in Bore's circuit will influence the PFB and NFB behavior- slightly! This means that not only will individual tubes with different gains will result in different output levels, but the HPF and LPF's will be slightly different in slope.
Listeningwise, I can say that the M269 was the first mic I used when I started pro recording at age 18, and my memory of it was that it was not as "hard" sounding as the 67's I ended up using in subsequent years.
-DB
Title: Re: Neumann M269c.
Post by: Klaus Heyne on April 26, 2004, 05:43:11 PM
dbock wrote on Mon, 26 April 2004 14:10


Listeningwise, I can say that the M269 was the first mic I used when I started pro recording at age 18, and my memory of it was that it was not as "hard" sounding as the 67's I ended up using in subsequent years.
-DB


I agree.
I attribute it to the AC701's dynamic characteristics.

Thanks for the explanation of frequency repsonse vs. tube plate load/transformer response.  Maybe this is indeed the reason for the slight variations in the extreme frequencies beween the two mics.