lastfuture
Offline
Freiburg, Germany

Hey,

I want to prosound the existing jack in my DMG but I'm not sure where to take GND from. I want to wire pre-pot L and R to the solder points on the audio daughter board where the 4-wire cable leads, cutting that cable's L and R wires in the process. There is already a GND wire leading to the daughter board. In my logic that should be fine since all GND is ideally the same. I have seen some tutorials however, cutting that existing GND wire from the daughter board and rewiring the GND pin from the volume pot there.

Is that really necessary? Is it different for pre- vs post-pot? Is there a difference? Or do the people instructing me to re-wire GND to the existing jack work off other tutorials for a separate jack and didn't think far enough?

Thanks for any clarifying answers smile

Alley Beach
Offline
clovis CA

it shouldnt matter, and if you notice there's static or feedback, then use the gnd from the pot. no biggie smile

wedanced
Offline
San Francisco

lets clarify first by saying that no ground is needed. it should already be. unless you cut the ground wire.

Apeshit
Offline

The question isn't whether ground is present or not in the circuit, but if there's an advantage to using the potentiometer's ground.

You may be aware that ground connections in circuits aren't always universal. "Ground" lines can have have different functions and should remain independent (i.e. analog ground/digital ground). But that isn't the case here. In theory, you may have better results with the potentiometer's ground, as the ground points among the board are at slightly different potentials. With that said, I doubt you'll notice any difference between the two.

thursdaycustoms
Offline
Cleveland, OH

What ASM said but simpler. Just don;t cut the ground wire and you'll be good. No need to solder a new ground.

lastfuture
Offline
Freiburg, Germany

Thanks guys. "Different potentials" was the expression I was looking for. I'll do as you all say and leave the existing ground line connected.
How would I recognize if the ground is at the wrong potential? My gut tells me to look for a DC offset after recording, but I think the daughter board handles DC bias If I understand what this particular tutorial states:

You might be wondering why I chose this spot instead of directly to the jacks. And to answer this question, it's because there are output de-coupling caps on this board which will assure no dc-coupling issues with other gear.

Last edited by lastfuture (Nov 4, 2012 9:02 am)