Capsule capacitance

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Lowfreq

Well-known member
Joined
May 28, 2005
Messages
574
Location
Christchurch, New Zealand
This may be something basic that I've missed, but I'm looking for a straight forward explanation of capsule capacitance.

Does a capsule with higher capacitance have a louder output? I found the volume difference between a CK12 styled capsule and an M7 capsule in a G7 microphone to be quite considerable, and it was my understanding that the CK12 had a higher capacitance. What makes the CK12 louder than the M7?

When I look at this page however, http://recordinghacks.com/capsules/ the CK12 capsules vary in capacitance a lot, and the M7 capsules sit right in the middle of them capacitance wise.

Even within the CK12 styled capsules, the range is from 64.4 pF (RK-12) to 97.4 pF (ADK GK12), so does that mean the RK-12 would have less output than the ADK GK12?
Even if I compared to AK12 to the RK12 (since they're in the same price range) there's a difference. Does the 3 micron diaghram make a difference compared to the 6 micron? Will the RK12 have less output than the AK12?

What are we looking for with capacitance? Is higher better? Is lower better? Where does Tim's CT12 capacitance sit ?

In the pursuit of a quiet tube mic, having a low output capsule seems to make it harder with noise, even when you have the lowest noise tube you can get your hands on, and the circuit is cleaned to perfection.

I'm ignoring the fact that we may choose a particular capsule for it's tone for now, just so I can understand things better.
I've searched and read through threads here, and I've read some of the "microphones" document from Neumann, but I'm still not that clear on the topic.


 
The capacitance of my capsule varies from 78pf to about 85pf.
Capacitance is only one ingredient in what determines capsule output.
The differences you are hearing between an M7 and CK12 are overall capsule design but also dampning.
A Sony  C37 capsule has very low output.
 
in addition to cleanliness and a quiet valve the power supply and distribution\cable\grounding can play a big role in noise floor
 
Tim Campbell said:
The capacitance of my capsule varies from 78pf to about 85pf.
Capacitance is only one ingredient in what determines capsule output.
The differences you are hearing between an M7 and CK12 are overall capsule design but also dampning.
A Sony  C37 capsule has very low output.

What is the, admittedly very small, difference in capacitance attributed to?

I assume that the physical dimensions of the brass and diaphragm mounting are nearly identical, but imagine that a minuscule difference in dimension is enough to cause a variance.

Perhaps the variance in capacitance is a result of the nature of the gold sputtering process?

Is the metal machining more consistent than the preparation of the diaphragm material?

I'm just curious, and will enjoy learning if you have any thoughts to share.

Thank You!
 
Is the idea that the layer of glue between the diaphragm and brass varies in thickness ever so slightly?

Thank You!
 
trans4funks1 said:
Is the idea that the layer of glue between the diaphragm and brass varies in thickness ever so slightly?

Thank You!

I would think you're right.  I don't know, just thinking of the gap between the "plates" or the dielectric varying with amounts of glue.  I bet it's an acquired technique and takes a lot of practice.
 
Sorry for using a decade old post but problem is same. I have two similar looking capsules of 26mm. One has 32pf and another has 70pf of capacitance, single diaphragm. What does that mean? The 70pf has more sensitive performance or more output?
 
Generally speaking capsule capacitance has a big influence on the noise floor generated by the impedance converter. As a rule of thumb 32 pF generate 6 dB more noise than 64 pF. Because effective membrane area is equal to all capsules of a batch difference in capsule capacitance indicate different distances from membrane to backplate. This leads to the fact that capsules (of the same type and batch) with higher capacitance are typically louder.
 
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