G7 - how do you wire C12 capsule?

About to put C12 capsule in G7 and I'm not sure how to wire it! Capsule hasasolder tag on each ring - are these joined together and biased to 80V. I've gone through the META and found only one photograph of a C12 capsule - but cant make out the wiring! :?

Look at the PCB layout PDF on Jakob's site.

Peace,
Al.

Yep, the layout combined with the schematic should describe all you need to know..

Jakob E.

Where did you get a C12 capsule from?

Michael

Got the capsule from a colleages "dead" 414. It's been lying around for about 4 years waiting to be fixed! He was reluctant to let me "play" with the capsule - until he tried my G9 lunchbox. Now I can "try" the capsule in the G7 - if he likes it - we'll share use of the mic - if not, he'll get the 414 repaired!


[quote author="gyraf"]Yep, the layout combined with the schematic should describe all you need to know..

Jakob E.[/quote]

Hello Jakob, sorry for appearing retarded, but I still don't understand the wiring. The schematic shows 3 connections to the capsule. I'm looking at the capsule now - it has 2 wires coming out the white plastic body - one each side; these are terminated to solder pins. Then there is a solder tag on each ring - checked for continuity between these but they're open cct. I've therefore got FOUR connections.
I've "borrowed" the capsule - my colleages "repair" guy reckons to have changed the capsule out in another mic and assures that the capsule is working. So I'm reluctant to connect the capsule until I know exactly what I'm doing. The dead 414 was dis-assembled so I dont know how the capsule was connected? Are the two solder tags connected together to form the centre 80V biased connection and then how can you tell which would be front or back - is the back where you can see the wires connected to the solder pins - or is this the front?
I'm just wary - I don't know if I'd damage the capsule if it was connected incorrectly?

basically there is no front or back. both sides (should be) the same. you can hear which side sounds better for cardioid operation.

yes, the ck12 used in 414 buls and c12vr has the two backplates wired seperatly: you connect them together in this application. and yes, the backplate gets the 80 volt polarisation via the 1gig and goes to the grid via the 1n polystren.
good luck - one tip - dont worry if the mic hums like hell as long as you didnt close the housing.

:thumb:

Thanks for the quick reply guys!
Just working on the pocket-size PSU :shock:

Soon be there - hopefully!

Cheers

Had a few problems with this one. I've done a verostrip/hardwire G7 in a rode NT2 body with an AKG C12 capsule.
Got sound from it but very thin sounding in omni (0V bias). Built a 9 position bias switch. On applying bias(positions 2 to 9) I was getting a nasty hum/buzz(100Hz) and could not figure it.
Anyhow, I left the project alone for a while and then coming back to it (with fresh eyes/brain) I discovered that I was applying the bias to the capsule side of the 33M resistor! I corrected this and now I got rid of the buzz.
The mic now operates with the polar pattern working as it should, BUT the mic sounds "thin" in omni and a "full" sound in fig8 but one side of capsule seems phase cancelled!
If you read the previous posts, the C12 capsule has 4 connections - 2 rings + 2 electrodes - I've connected the rings together to create a 3 pin capsule.
Would any damage result if I was to connect a ring and electrode together to form the centre "pin", biased to 80V. I would then connect the remaining ring to 0V and the remaining electrode to polar/bias voltage.

Sorry - forgot to mention - had a look at the 414buls service manual - looks like they got a pin/ring/pin/ring thing goin' on!

i´m not sure, but i think you connected the capsule wrong.
the yellow wires are the backplates, you have to connect them together, not the rings like you describe in your post.


regards, max

:grin: thanks max - will try after the football!