Graphene Diaphragm

[abbey road d enfer]

What about the Shure ribbons?

Whadda you mean?

 

[Gus]

I wonder if it some thing like the Roswellite? I have not seen any of the ribbon microphones in the links.

http://recordinghacks.com/microphones/tag/roswellite
https://microphonium.blogspot.com/2008/02/roswellite-faq-frequently-asked.html

 

[ccaudle]

single most common fault with Neumann nickel diaphrams is burning holes in the diaphram from them touching the backplate.

I would not have guessed that. The continuous current would be really low through the polarizing resistor, and the charge is pretty low in a few tens of pf. Is it due due all of the charge concentrating through a microscopic spot on the diaphragm, and generating enough heat to cause localized melting?

I have never seen frequency response plots from a km56, is it comparable to something like a km84?
Stated differently, is the performance of a sdc dominated by the air chamber, or does the diaphragm property make a large difference?

 

[Tim Campbell]

I would not have guessed that. The continuous current would be really low through the polarizing resistor, and the charge is pretty low in a few tens of pf. Is it due due all of the charge concentrating through a microscopic spot on the diaphragm, and generating enough heat to cause localized melting?

I have never seen frequency response plots from a km56, is it comparable to something like a km84?
Stated differently, is the performance of a sdc dominated by the air chamber, or does the diaphragm property make a large difference?

I can't seem to upload any freq. charts but there is a ton of info on the web also about this arcing of nickel membranes. These mics have been in use since the 50's. Neumann even raised the membrane resonance freq. in the 60's to keep them from shorting but it changed the freq. response resulting in less low end.

 

[Gus]

Off topic
I have 3 gefell m70s with holes in the Ni membranes.
If they were repaired with PET would that change the sound?
Has anyone "repaired" them with Mylar to avoid the arcing?

I have a solid state KM54 like circuit idea simmed I was thinking of trying with the capsules

 

[Matt Nolan]

I would not have guessed that. The continuous current would be really low through the polarizing resistor, and the charge is pretty low in a few tens of pf. Is it due due all of the charge concentrating through a microscopic spot on the diaphragm, and generating enough heat to cause localized melting?

I might be totally off here with my quick and dirty calculation, but I think with an instantaneous short, you're getting rid of a nano-Coulomb or so in, say, half a nanosecond, which is an average of 2 Amps, concentrated in a tiny area of 0.8 micron thick Nickel.

 

[Tim Campbell]

Off topic
I have 3 gefell m70s with holes in the Ni membranes.
If they were repaired with PET would that change the sound?
Has anyone "repaired" them with Mylar to avoid the arcing?

I have a solid state KM54 like circuit idea simmed I was thinking of trying with the capsules

Gus if you send me one I'll try it for you. It won't sound like the original, nickel has a unique aggressiveness but that doesn't mean it won't sound good. They are really well engineered capsules.

I have done some KM54 types with aluminum like the M50 capsule but I don't have time to explore it further.

 

[OPR]

Off topic
I have 3 gefell m70s with holes in the Ni membranes.
If they were repaired with PET would that change the sound?
Has anyone "repaired" them with Mylar to avoid the arcing?

I have a solid state KM54 like circuit idea simmed I was thinking of trying with the capsules

I've repaired M70 capsules with 3um Aluminum coated mylar. It definitely sounded different,Not as bright, but still sounded good in its own way.

 

[Icantthinkofaname]

I own 3 KM56's. The single most common fault with Neumann nickel diaphrams is burning holes in the diaphram from them touching the backplate. Thiersch makes a good deal of his living from these repairs as he is one of the few who does this work. I have seen at least a dozen of them with this problem. You were lucky or gentle with them.

I believe Danmarks Radio was the largest single purchaser of KM56's.

I would recommend anyone buying KM54/56 microphones to examine the diaphrams before you buy them.





Klaus Heyne
Weaknesses: super-fragile nickel capsules with tendency to develop arc holes from contact between metal diaphragm and metal backplate.

Would the sE Electronic T2 capsule suffer from this risk? It's advertised as being titanium.

 

[gyraf]

..what SE means is Ti-sputtered-on-mylar. Saves gold.