Tubemooley
Well-known member
I am looking for extra double triple confirmation on one question today. I am building an ElaM251 clone with the kit from mic-parts.com. I started with an Avantone CV-12 donor. I have a brand new Heiserman HK12 capsule from Heiserman. I spoke with Eric Heiserman yesterday. He confirmed for me that the two screws already screwed into the side plastic spacer area (when I received it) are indeed the two backplate screws. Use those two screw holes only. Don't mix them up. Then there are four other screw holes where the saddle lines up with each pair; choose one pair.
I have all of my 251 schematics, my Apex 460 to C12 schematics, and all of Oliver's schematics.
Here's my question: The two backplates get wired together and that one node goes to the 1000 pF polystyrene capacitor and the B+ divided by 2 polarization voltage through the 1 Gig resistor. Right?
a. Front diaphragm goes to GND.
b. Rear diaphragm receives the remote pattern voltage.
c. Signal comes off the two backplates and goes to 1000 pF and then to the grid of the tube.
Right? Please advise.
I have photos of everything. I do not like to put the DMM on the capsules. That can be dangerous to the capsule.
Thanks, Dana Walcott.
I have all of my 251 schematics, my Apex 460 to C12 schematics, and all of Oliver's schematics.
Here's my question: The two backplates get wired together and that one node goes to the 1000 pF polystyrene capacitor and the B+ divided by 2 polarization voltage through the 1 Gig resistor. Right?
a. Front diaphragm goes to GND.
b. Rear diaphragm receives the remote pattern voltage.
c. Signal comes off the two backplates and goes to 1000 pF and then to the grid of the tube.
Right? Please advise.
I have photos of everything. I do not like to put the DMM on the capsules. That can be dangerous to the capsule.
Thanks, Dana Walcott.
