32mm K67 Alctron capsule

[ln76d]

Who can beat the alctron?
Their cheap 32mm capsules can handle 120V of polarisation voltage without any problem
What i discovered also is that in the circuit am working on, the worst response is below 50V and also between 65V and 72V.

 

[Khron]

Just like Mythbusters - if it's worth doing, it's worth over-doing ;D

 

[ln76d]

For polarisation voltages under 75V the  sweetspot is 62V

 

[homero.leal]

Wich capsule do you mean, ln76d?

The one wich comes on the HST-11A?

Thank you and best regards!

HL

 

[ln76d]

Yes, hst-11a and a half of chinese LDC.

BTW -  i think it can handle higher voltages due to thicker shims between diaphragm and backplate.
It use metal shims.

 

[micaddict]

Yes, hst-11a and a half of chinese LDC.

BTW -  i think it can handle higher voltages due to thicker shims between diaphragm and backplate.
It use metal shims.

A greater distance from the backplate would indeed help in this regard (but has cons, too).

Part  (!) of the reason it can handle higher voltages could also lie in the fact that is is slightly smaller in diameter than the 34 and 35mm capsules.
Same for this one:
http://microphone-parts.com/collections/capsules/products/rk7-microphone-capsule
But that one ^ has 6 micron Mylar.
Strangely, some sources indicate that the infamous Chinese "K67" (the one discussed in this thread) has 3 micron Mylar:
http://www.nady.com/products/microphones-studio-wired/tcm-1050/
Nothing is certain, mind. E.g. it also states it has a 12AT7 tube which often actually is a 12AX7.

Thinner Mylar would suggest lower voltage handling capabilities raher than the opposite, no?
Well, the actual tensioning plays a part too, so theoretically it could be tight.
But in the longer term at least, one would expect it to stretch more.

 

[James-F]

Bumping an old thread.

For polarisation voltages under 75V the sweetspot is 62V

What does 'sweetspot' mean in capsule terms?
Besides raising the sensitivity and lowering self noise, what are the sonic effects of pushing the polarization voltage above 60v with those capsules?

 

[kingkorg]

No audible or measurable difference. Tested by altering voltage on tube mic psu by playing pink noise without changing the position or any other variable. Recorded files canceled 100% regardless of voltage 40-80V. Tested Rode NT1 capsule also up to 100v, no difference.

 

[James-F]

Thank you, very useful information.

 

[James-F]

Another piece of information I want to share;
In a Schoeps circuit, when the backplate is directly polarized and the diaphragm is wired directly to the Gate of the JFET you have two positive voltages that repel each other electrically, that prevents the possibility of collapsing/sticking of the diaphragm until the other side goes below 0vDC and becomes negative.

I think microphones that have either side referenced to ground are much more prone to collapsing/sticking because of the negative swing portion of an AC signal, especially wind puffs.
I still consider this just a theory that is worth investigating further.

 

[James-F]

I see, thank you.

 

[Unips]

No audible or measurable difference. Tested by altering voltage on tube mic psu by playing pink noise without changing the position or any other variable. Recorded files canceled 100% regardless of voltage 40-80V. Tested Rode NT1 capsule also up to 100v, no difference.

Is it only the polarization voltage you are changing; or also B+?