Valve Mic Cable for G7?

[marktokach]

Ok so I need to connect the IEC to the psu case with a screw, then come of that to pin 1 pcb, then to 7 pin xlr, then to 3 pin xlr, which then goes to pin 1 of mic cable connector, which then goes to shield of cable? Sorry for needing such exacting details but I don't want to fry me or the mic.

 

[marktokach]

"If you look closely, the G7 PCB actually connects the heater and audio 'zeros' (pins 1 and 7) inside the mic."

Isn't pin 1 ground for +160 and pin 7 heater ground? I see audio ground on pin 4 and pin 3 +audio.I could be misinterpreting it.

 

[zebra50]

>Ok so I need to connect the IEC to the psu case with a screw,

Yes

>then come of that to pin 1 pcb,  then to 7 pin xlr,

One or the other. Normally the audio circuit is connected to the chassis at one point only (and this in itself is contentious!). As I said in my PM, the audio and heater grounds are are connected together in the PCB of the mic.

The shield should be grounded in the mic.

>> then to 3 pin xlr, which then goes to pin 1 of mic cable connector, which then goes to shield of cable?

Where did pin 3 come from? I don't see pin three as ground in the original G7 documents, and you have it above as Audio+.

"If you look closely, the G7 PCB actually connects the heater and audio 'zeros' (pins 1 and 7) inside the mic."

Isn't pin 1 ground for +160 and pin 7 heater ground?

Yes, - the B+ (160V) supply becomes the tube audio circuit. And look at the PCB of the mic - the trace on the outside of the PCB runs from pin 1 to pin 7. And look at the schematic.

I see audio ground on pin 4 and pin 3 +audio.I could be misinterpreting it.

Audio plus and audio minus - it is a balanced output.

 

[marktokach]

>> then to 3 pin xlr, which then goes to pin 1 of mic cable connector, which then goes to shield of cable?

  Where did pin 3 come from? I don't see pin three as ground in the original G7 documents, and you have it above as Audio+

I was talking about the 3 pin xlr that the output of the mic comes out of and into your pre. I have that and all other grounds in psu hooked together like a star ground. Thanks for your help!

 

[zebra50]

OK, I get you now.

On the three pin XLR, with a balanced output, pin 1 is ground, pin 2 is 'hot', or audio +, and pin three is 'cold', or audio minus.

So you should not ground pin three unless you want to run unbalanced for some reason. With a microphone output, you always want to run balanced if you can.

 

[marktokach]

I'm finally getting it! Thanks.
Shield needs to be grounded in mic. Does that mean take pin 1 of 7pin xlr at mic and wire it to the side the tube or is it already grounded at the xlr? And I got to run a wire from there to the screen also? Sorry but this had been the hardest part for me to understand yet. Obviously!