PCB layout question - merging of pwr and sig grounds?

[Family Hoof]

I do 2 layer analog audio boards with audio traces on top and power + ground on the bottom. The entire audio path treats bottom layer like ground plane. When there is an on board power supply I lay it out on that same plane layer but with it's own ground trace or star ground and then join that to the ground plane at one point only (underneath main filter caps). Until now this has made more sense to me than to have the power supply ground tap into the plane at each point like the audio path, but maybe this is not the best way to go about it?? What do you think is best in this situation and why?

Thanks! :guinness:

 

[Svart]

well, grounds can be a tricky tricky thing sometimes and i've found that even if you do things "correctly" that sometimes you still get into trouble. I find that there is no "correct" way though doing things in a sensible and guided way is still best. You aren't going to see a lot of trouble from an analog ground as long as it's not terribly noisy(signs of other issues..). The other deadly grounding sin is of course.. digital. you have to separate the A and D grounds but keep them at the same potential. This is where you join the two grounds at one point usually through a high value ferrite, usually where the signals would be converted(under the ADC/DAC). this keeps the analog ground from bouncing. As far as power and analog audio grounds are concerned, there should be as least resistance as possible(you don't want current noise on ground from too high resistance), wide and short traces(not thin antenna traces..) with no loops(as seen in other threads causing trouble!), moving outwards like a star. always try to cross digital paths at right angles and also try to keep a fair distance away from any power traces that pass a lot of current..( capacitive coupling).

I've read a lot more tricks over the years but for such low power levels you shouldn't be too concerned.