Gachet

Re: Official G7 microphone help thread
« Reply #100 on: June 03, 2019, 03:28:10 PM »
Hello

How do you guys wire the CT12?
The two pins on the side of the capsule goes to center?


gyraf

Re: Official G7 microphone help thread
« Reply #101 on: June 04, 2019, 04:15:43 AM »
yes, the two on the side are backplates (connect those together and to the +50-60V), the membrane-retaining-ring-connections are front/back

Jakob E.
..note to self: don't let Harman run your company..

Gachet

Re: Official G7 microphone help thread
« Reply #102 on: June 04, 2019, 08:39:48 AM »
Thank you Jacob

So my capsule is wired correctly.
I've tested the connections between the capsule and the tube.
I've measured the styroflex to make sure they are ok.
I reversed the capsule front and back...

But I'm still having the same problem:

When I switch directivities I have:

Figure 8: Lots of lo end , a bit woofy
Cardio: A great sound pretty well balanced
Omni: No lo end at all, like a 500Hz Hi pass...

I recorded it so it's not  the phase issue beetween  headphone and mouth.

Any suggestion?

rcphillips

Re: Official G7 microphone help thread
« Reply #103 on: July 18, 2020, 11:54:59 AM »
[posting to the official help thread now]
I'm finally getting around to building a G7 (majority of parts have been purchased and sitting in a box for a decade or so), and after reading the META and META-META, I still have some questions, maybe some of you all could help me?

[project details]
PCBs: Gustav's
Body: Chunger's Alctron MK47
Capsule: BeesNeez M7
Tube: PF86
PSU Case: Dan's PSU case
Transformers: Lundahl LL1538
Appropriate mods: in the PSU pattern switching section 100k+100k resistor becomes 40k + 50k+50k; in the mic itself, the second 470k resistor becomes 282k (maybe higher, depending on actual measurements) to lower the polarization voltage of the capsule - I think the combination of changes should result in the heater voltage being around 4-4.5v for the PF86 (I think that's what I've read, and calculated)

[mic pcb questions]
- For connecting the tube socket pcb to the main pcb, should I just use a bunch of thick resistor leads bent at a close-to-90-degree angle? [Jakob says "yes", thank you!]

[PSU and PSU case questions]
- Should I just use wire nuts (twist-on wire connectors, like: https://en.wikipedia.org/wiki/Twist-on_wire_connector ) for connecting things like the two toroids? Seems like it would be fine.

- I'd like to add a power indicator lamp; it looks like I could get a panel mount one like:
https://www.mouser.com/ProductDetail/VCC/2152A6?qs=I7nE1oQSFs9skzm1Siom9g%3D%3D   
https://www.mouser.com/ProductDetail/VCC/2120A3?qs=rHu0DOexXLC4pEbHTBL8Fg%3D%3D     

and wire it to the power switch. Does that make sense to do, or would you recommend something different?

- Any preferred pattern select switches? I have some Lorlin rotary 2pole/6position, but I'd have to spend some time widening the hole in the case (the rotary shaft is maybe 1/32-1/16" too  large to fit).

- Any preferred standoffs + bottom screws for mounting the PSU board to the case?

- For the panel mount XLR (Neutrik D series) and IEC outlet (Schurter 6200.2100), are some flat 4-40 machine screws appropriate, or is there a better choice?
-----------------

Thank you in advance for any and all help you can give.

Cheers,
-Robert