American octal steel tubes in LDC microphones?

[GeorgeToledo]

Any patents would have long expired. I believe Neumann has dinged parties on the headbasket shape they didn’t invent as a matter of trade dress/trademark, not patent. I am pretty darn sure it really has to *look* like the Neumann U67/87 product headbasket in all regards.

 

[abbey road d enfer]

Personally, I find those LDCs where the head basket is considerably wider at the top, to look really goofy.

Once you realize it's done on purpose with a good technical justification, goofiness becomes bauhaus.
https://en.wikipedia.org/wiki/Utilitarianism

 

[k brown]

Bauhaus, eh?

I'll bau-out ; - )

 

[soliloqueen]

Once you realize it's done on purpose with a good technical justification, goofiness becomes bauhaus.
https://en.wikipedia.org/wiki/Utilitarianism

i think it would be neat to see some microphones with completely inelegant, ugly headbaskets that are acoustically ideal. just absolutely absurd designs engineered for the sole purpose of conducting sound through them and absent any other intention or convention

 

[k brown]

i think it would be neat to see some microphones with completely inelegant, ugly headbaskets that are acoustically ideal. just absolutely absurd designs engineered for the sole purpose of conducting sound through them and absent any other intention or convention

Form following function, utterly.

I leave it to others - I couldn't bring myself to do it. Too important to me that my tools are also beautiful.

 

[rock soderstrom]

To be on topic, I can say that about ten years ago I restored two bottle microphones, CMV 3 and 5.

This post by member moamps sent me on an exciting journey last night into the history of the Neumann CMV3 microphone.

Of course I already knew this milestone in microphone history more or less, but what I didn't realise was that this microphone and its direct successors have formed a really extensive product universe.

The following document lists all(?) model variants (including capsules). It is interesting to note how many different types of tubes were used. From the original RE084k to various "Wehrmacht" tubes, but also EF12K, VF14, EC92, EF95, EF86, EF806s and ECC81 were used.

http://www.jogis-roehrenbude.de/Roe...Neumann-Mikro/Flasche/Uebersicht_Mikrofon.pdf
In the post-war model variants CMV 5a and 5B II, EF6, EF37 and even the American 6J7 were used. This closes the circle to the original topic of this thread. I am really surprised about this turn of events and would be very pleased if someone had photographic evidence of this transatlantic union.

If you are interested, here is a set of really wonderful photos of the Condensator Mikrofon Verstärker 3. Very detailed shots of a CMV3 in original condition. I think the technical details for this time period are really outstanding.

http://www.analog-service.com/mikrofon-neumann-telefunken-cmv3.html
further beautiful photos and info are here:

http://www.jogis-roehrenbude.de/Roehren-Geschichtliches/Neumann-Mikro/Flasche/Flasche.htm
PS: How the hell does this "Betriebsstandanzeiger" (operating status indicator) in the heating circuit work?

 

[abbey road d enfer]

i think it would be neat to see some microphones with completely inelegant, ugly headbaskets that are acoustically ideal. just absolutely absurd designs engineered for the sole purpose of conducting sound through them and absent any other intention or convention

Ugliness is in the eye of beholder.

 

[abbey road d enfer]

PS: How the hell does this "Betriebsstandanzeiger" (operating status indicator) in the heating circuit work?

It('s an electromagnetic device, actually a derivative of the d'Arsonval galvanometer, where the scale is constituted of black and white sectors rotating below a graticule consisting of two [EDIT: four] openings in the form of quadrants.
Depending on current, a more or less important part of the white sector is apparent.
It seems the one in the pictures is stuck in the "on" position.

 

[rock soderstrom]

It('s an electromagnetic device, actually a derivative of the d'Arsonval galvanometer, where the scale is constituted of black and white sectors rotating below a graticule consisting of two openings in the form of quadrants.
Depending on current, a more or less important part of the white sector is apparent.

Wow, thanks

 

[abbey road d enfer]

IIRC, they were commonly used in telephone systems last century.

 

[rock soderstrom]

IIRC, they were commonly used in telephone systems last century.

Okay. I haven't seen one in real life yet, that was way before my time.

 

[rock soderstrom]

What I also find very impressive is how much effort the designers have made against microphonics. That seems to have been a big issue with the tubes available. I think I will encounter that in my steel tube experiments as well.

Edit: I think the dual use for recording and PA also played a role.

 

[abbey road d enfer]

Also impressive is the fact that, in the Udo Heusinger document, the foam around the tube is intact after so many years.

 

[abbey road d enfer]

Okay. I haven't seen one in real life yet, that was way before my time.

You may have a glimpse at one in a period movie.

 

[rock soderstrom]

Also impressive is the fact that, in the Udo Heusinger document, the foam around the tube is intact after so many years.

I also wondered a lot about that. Normally, after such a long time, only crumbs or some kind of soup remains from the foam.

They had very durable materials

 

[rock soderstrom]

You may have a glimpse at one in a period movie.

That or a visit to the Deutsches Technikmuseum in Berlin could show this kind of indicator. I haven't been there for a long time.

https://technikmuseum.berlin/

 

[gyraf]

my favorite museum, unironically

That or a visit to the Deutsches Technikmuseum in Berlin could show this kind of indicator. I haven't been there for a long time.

https://technikmuseum.berlin/

 

[GeorgeToledo]

It’s because it’s probably not typical foam, it’s rubber if it’s the usual stuff. (I didn’t click through). Orange open cell rubber sponge.

 

[GeorgeToledo]

https://therubbercompany.com/sponge...sponge-sheeting/orange-open-cell-sponge-sheet

 

[terry setter]

I use a dented t.Bone SC450 USB as a test body. The circuit, as already mentioned several times, is a rudimentary SELA T12. Less is not possible...
View attachment 105840
View attachment 105841View attachment 105842

Wow, just looking at that transformer I'm going to speculate that this mic will have very significant low frequency distortion issues. And, sadly, low frequency distortions can add audible harmonic content throughout the entire audible spectrum, not just the upper octave or so, as some other circuit problems do.