Multipin connector/ground

Depends on the signals. If they are digital, then you need a ground for each signal. In fact, the ground arrangement on the connector can even matter.

If they are analog, maybe not, but I would have one ground return for L and one for R channel.

Steve N.
Empirical Audio

Drumthumb said:

Thank you - also - what is the difference between a drain and a shield/ground?

Click to expand...

Now that is a very complicated question, indeed. The word 'ground' has many meanings and in the audiophile world, it has many more incorrect meanings.

ground = common reference point or path to that common point.

shield/screen = metal chassis/enclosure or metal wrap around a cable.

drain = a wire to connect one shield to another. it may have other meanings.

earth = Planet Earth. it too may have other meanings.

There is a lot of confusion created over the term ground.

The term ground really refers to earth ground, which can be connected to the signal return paths/DC-common at many points or only at one point in a given circuit.

For most signals, there is a return path/DC-common that might be a ground-plane or a wire in a cable. Like all electrical signals, there must be a forward current path and a return current path, just like batteries and bulbs. Digital and Analog audio is no different. The shield in a cable may only be connected to that DC common or earth ground at one end. There will usually be other wires in the cable that carry the return currents back to the source. Generally, it is not optimum to also have the shield carrying the return current back to the source. There are exceptions, as in coaxial cables. The drain wire is usually just a wire that touches the shield so that it can easily be soldered. Soldering a shield can be problematic, particularly if the shield is sheet aluminum, so the drain wire is added. Good shields are often sheet aluminum covered by a woven mesh of fine wires and usually have a drain wire.

The other confusion is "star-grounding", which is usually accepted as a good practice. It can be good, as long as it is done properly. When properly done, it is primarily about connecting the earth ground to the signal returns at the optimum location in the topology without causing the return current of the signals to take round-about paths. It also can cause all of the return currents to go back to the source power supply without sharing wires between loads. It serves to separate the power currents from the signal currents and eliminate "crosstalk" in the power subsystem.

Steve N.
Empirical Audio