grounds in active crossover

[georgiano]

I'm designing PCB for Rod Eliott's active crossover

here is the link to the project
http://sound.westhost.com/project81.htm

as there is no high currents involved, is star grounding necessary?
may I skip it and do groundings in more free manner (of course with no ground loops)

[justblair]

Originally posted by georgiano
I'm designing PCB for Rod Eliott's active crossover

here is the link to the project
http://sound.westhost.com/project81.htm

as there is no high currents involved, is star grounding necessary?
may I skip it and do groundings in more free manner (of course with no ground loops)

Watching closely, I have this design in mind for my next amp, gathering the parts as we speak.

What package are you using for the design work?

Care to share the files?

And how do you plan implementing, are you putting the whole crossover on one pcb. I was thinking about on multiple repeated crossover sections to produce a modular system.

Haven't started the design of this bit yet, so I cant really answer your question with suggestions....

[georgiano]

I'll be using Eagle 5.0, shure can share files.

any help with grounds, anyone?
also, is capacitor type selection critical?

[sek]

Hi,

will you have the PCB manufactured (sent out), or do yo DIY?

I'm asking because doing the PCB yourself has a whole lot of implications on your PCB design, including grounding. Through-hole capacitors cannot be soldered from the bottom side, layers (board sides) can only be changed at component pins (or dedicated pin vias), etc. And yes, capacitor choice can have a significant influence on frequency accuracy and sound quality.

But generally, ground planes are as good as star grounds, as long as care is stil being taken on the current paths, impedance levels and IC decoupling measures. In essence: do your layout as if a star grounding scheme was being used. Once this has been accomplished, a ground plane is easier to design/manufacture and can be still as good.



Cheers,
Sebastian.

[gainphile]

I've done many active crossover, all on veroboard. Yes, star ground is very important, otherwise you will get hum.

[sek]

Originally posted by gainphile
I've done many active crossover, all on veroboard. Yes, star ground is very important, otherwise you will get hum.

I would argue this, although I agree that proper grounding is mandatory. But as veroboard won't allow ground planes, we'll never find out.

This would of course all be different in case we were talking high frequency applications...

[georgiano]

which grounding scheme is better?
do you see any obvious design flaws? (ground-wise)

here are pdf files for schematic and PCB
www.georgiano.net/images/crossover.pdf
www.georgiano.net/images/crossover_1.pdf
www.georgiano.net/images/crossover_2.pdf






I higly approciate any help

[AndrewT]

I count ten items connected to the ground trace around the PCB edge.
Some are connected to the IC pins and others to passive devices.
I suspect you are combining clean and dirty returns into a series of linked impedances (traces with resistance and inductance). = big problems.

[sek]

That and this is not a ground plane!

Also, you could shorten some traces (and thus board size) considerably.

[georgiano]

is it that bad? both of them?

do you mean by ground plane double sided board with second layer as a ground?

as I have concluded from what I've read on the net low current grounds should "flow" into high current ones, just like rivers. and if there are no level differences grounding should be no problem.

wrong?