First pcb.

[ambed]

Its actually no my pcb, i found it on internet and i made some changes. Can you tell something about pcb? thanks.

[jazzman06]

i know where d you found this! and what changen do yoy do? at the beggining it' very good pcb without any changes

[peranders]

Personally I would place the star ground under the output filter.

[ambed]

i think it will be werry dificult move v-gnd under output filter,I can move this point for some mm to right side, nearer to output. what you say about this?

[bbp]

Originally posted by ambed
i think it will be werry dificult move v-gnd under output filter,I can move this point for some mm to right side, nearer to output. what you say about this?

two 470uF capacitor are needed near the CHIP for PSU bypassing

[ambed]

and now will be better??

[pacificblue]

Originally posted by ambed
i think it will be werry dificult move v-gnd under output filter

No. It would actually make most ground traces shorter and the overall layout cleaner.

[ambed]

maybe you can give some good layout which I can a little bit remake ?

[ambed]

Which ground are better star or ground like in pcb??

[pacificblue]

That question is a bit unspecific. Any ground scheme is a compromise of several aspects, so you have to define in which aspect you want it to be better.
Better in stability, ease of implementation, economy, etc.

Usually you strife to have the shortest possible path from each component to a star-point at the lowest potential (0V). However the layout will not always permit for the shortest path to every single component. Using a dedicated wire from each component to that point is often not practical. Many wires are also more expensive than few wires, and they take a lot of time to connect and arrange. They also form nice antennas to pick up disturbances from the surroundings.
On the other hand it is not good to unite all return paths in a single wire, because the combined currents lead to a voltage drop across that wire, which means that the ground reference is shifted from 0 V. Signal linearity will be affected negatively by that.

Conclusion is, you have to find the best compromise for your specific project. Start by drawing a star-ground scheme. Then group the ground returns according to their character. E. g. power ground, signal ground or clean, dirty, etc. Analyze, which currents can be combined according to their character and, which currents combined are low enough to not produce a big voltage drop across the wire and which references must absolutely be at the same potential, thus must be combined into a single wire. Then you can form sub-stars e. g. on a PCB.