Wiring the G9 inputs, very strange happenings :0)

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caps

Well-known member
Joined
Jun 7, 2004
Messages
196
Location
Australia
Hi guys,

Hoping someone can help with getting the G9 finally finished. Seems to be quite a few round here doing it currently, and of course many that have done it in the past.

My problem revolves around the two channel inputs, or so it seems.

As it stands, the signal coming out of the G9 is quite noisy and scratchy, and low level. Its obviously not quite right.

However, if I press a finger against the input pins on the XLR connector it will pass signal at a level and noise factor that seems correct. Take the finger off, and its back to how it is discribed above.

Strnage thing is that its exactly the same on both channels.

I have used shieled cable for the output connections from the PCB, but the inputs I have wired with just standard hook up wire.

Should I rewire the input XLR's with shielded cable ,and wire the shield to the earth tab on the XLR? As I did for the outputs ?

I used hook up wire thinking it wouldnt matter as the connections to the input XLR's are quite short.

I have re-terminated the wires on both XLR's twice, but it dosent fix it.

The finger pressing against the XLR's should be a indication of what the problem may be shouldnt it ?

Many thanks for any suggestions. I am very eager to get it done and in the rack, and continue to make music. :grin:
 
Hi !

Have you grounded pin 1 on the XLR ?

The shield should be connected to pin 1 on both the XLR:s.
One of the inputs XLR:s pin 1 should also be connected to the chassis.
At least this is how I did it, and mine is fine :grin:
Seems to me like you have improper grounding...
 
[quote author="MrZpliff"]Hi !

Have you grounded pin 1 on the XLR ?

The shield should be connected to pin 1 on both the XLR:s.
One of the inputs XLR:s pin 1 should also be connected to the chassis.
At least this is how I did it, and mine is fine :grin:
Seems to me like you have improper grounding...[/quote]

On the input XLR's, pin 1 is connected to pin one of the other input XLR, that is then connected to chassis with the power ground as well.

On the outputs, I have connected the shield from the cable to the ground tab on the XLR. Pin 1 on the outputs is not connected to ground.

Pin 1 in this case is connected to the PCB point that is neither + or -.

Or in other words, you have 3 wires to each output. I have connected + to pin 2, - to pin 3, and the other to pin 1.

Incorrect grounding makes alot of sense now that you mention, just gotta figure the exact correct way of doing it. :grin:
 
Zpliff,

If the shield should go to pin 1...

and on both ins and outs you have THREE connections...

+ goes to 2, - to 3...

wheres the other one go ?
 
Hmmm...I think you should try it like this:

Connect the shield to pin 1 on each XLR and connect each one separately to the PCB. Then pin 2 (+) and Pin 3 (-).

All pins should be individually connected to the PCB.

Then solder a little jumper from input XLR pin 1 directly to the chassis.
Your chassis must be connected to the AC ground. (Otherwise you may end up toast !)
 

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