797 audio SD capsules on Takstar CM60 body ?

[Khron]

"Between R2 and R8" is kinda-sorta meaningless. Which end of R8, and what is each end of R8 connected to?

If anything, R6 and R7 are the 2.2k drain and source resistors for the JFET. I can't tell which is which from the picture of the board, but one end of the source resistor is supposed to be connected to ground.

But regardless, are you getting that -31v between which end of R12, and a known reliable ground point (XLR pin 1, for example)?

 

[Chrisfromthepast]

"Between R2 and R8" is kinda-sorta meaningless. Which end of R8, and what is each end of R8 connected to?

Right here:
Black lead to pin 1 of xlr

 

[Khron]

Ok, so is THAT how you got that -31v? In fact, you could've just measured across C12; its other end should be going to ground - bit of a brainfart on my side as well...

If that's the case, -31v downstream of 1meg might even be stretching towards -60v, if your meter's input impedance is around 1meg (remember your resistor-divider math).

 

[Chrisfromthepast]

Yeah, I think we’re saying the same thing.
-31 v across c12 with this aneng an8008 cheapo meter.

Thanks for walking me through the polarity swap!
I hope this helps the OP build a useful omni mic.

 

[Khron]

Ok, glad we managed to end up on the same page then. So the actual unloaded voltage there should end up in the region of 45-60v (guesstimation) Plenty for an SDC...

 

[Chrisfromthepast]

Here is a plot of the formerly cardioid 22mm electret, with backplateholes plugged with super glue.

Definitely not the worst sounding capsule.
The output is out of polarity, so pins 2 and 3 should be swapped, if this mod is kept by anyone reading along.

 

[kingkorg]

Here is a plot of the formerly cardioid 22mm electret, with backplateholes plugged with super glue.
View attachment 108904
Definitely not the worst sounding capsule.
The output is out of polarity, so pins 2 and 3 should be swapped, if this mod is kept by anyone reading along.

Looks right, and good. This capsule construction performs best as an omni, even if you mod it this way.