Vanguard V44S - Grounding oddity

[amplexus]

Had to replace the 5 pin XLRF on my V44s today- discovered the grounding configuration is... I don't know if it's wrong per se, but it feels like it's not ideal.

Basically it's a 6 conductor shielded cable, pins 1, 2, 4, and 5 are the audio hot and cold for each capsule. Pin 3 is tied to two conductors in the cable in parallel and is connected to the PCB common. The shield is connected to the shell tab on the XLR's. So far so hoopy.

But then every pin 3 connection is jumpered to the shell tab/shield wire. In both XLR shells and in the mic body AND in the breakout box. So basically the sheild, mic chassis, and PCB common, and Pin 1's in the breakout box are all connected in parallel at every single possible connection point.

Would this not have been a better grounding structure with a 4 conductor shielded cable, wired with the shield to pin 3 and nothing connected to the XLR shell tabs? With the two conductors tied in parallel to the shield at basically ever connection point, it seems like then any RF/EMI on the shield would be let inside right alongside the twisted signal conductors.

 

[abbey road d enfer]

Had to replace the 5 pin XLRF on my V44s today- discovered the grounding configuration is... I don't know if it's wrong per se, but it feels like it's not ideal.

What is a V44? can you draw a schematic of what you think is a problem?

 

[musipol]

Is this a stereo mic?

 

[amplexus]

It's a stereo condenser microphone. Quite excellent actually. V44S gen2 Stereo Condenser – Vanguard Audio Labs

This is a very crude quick sketch. Basically it just looks like redundant grounding everywhere, and pin 1 problems in the breakout box. A bunch of tiny ground loops almost. Though i suppose in theory they're all parallel conductors to ground so maybe not an issue? It just feels like not a very thoughtful execution. "Oh hey, just just make everything grounded. lots of grounds! tie everything at 0V or ground to each other everywhere you can!"

Green lines are insulated 'conductors', black lines are either shield braid or bare jumper wires between the 'conductor' and chassis/shell, or indicate the XLR shell connection to the device 'ground'

Like again, I feel that this could have been done better with a 4C shielded cable, leaving the sheild as pin 1 connected as per good practices.

 

[radardoug]

Did the microphone work fine before you changed the connector? If so, wire it up exactly how it was and move on.

 

[amplexus]

Did the microphone work fine before you changed the connector? If so, wire it up exactly how it was and move on.

Lots of gear with pin 1 problems "work". That doesn't mean they're as quiet as they could be, or that they'll stay that way in every situation. And it's certainly not a reason not to correct bad practices if they have the potential to cause issues.

 

[abbey road d enfer]

This is a very crude quick sketch. Basically it just looks like redundant grounding everywhere

Redundant is not necessarily evil. It would be if the mic was connected to earth, but it's not.

, and pin 1 problems in the breakout box.

What Pin 1 problem?

A bunch of tiny ground loops almost.

Loops are a problem if current is allowed to circulate, which is not the case here.

 

[amplexus]

What Pin 1 problem?

Is the fact that all the pin 1's are connected to each other directly, and also tied to the chassis not a violation of the pin 1 rule?

 

[radardoug]

That grounding scheme is exactly what Klaus Heyne and Neumann recomend, so its probably fine.