Mixing a Digital Board with GC

[Doovieman]

Hi-
I'm working on a regulated/buffered GC, but am also adding a digital board for some extra fun. I was wondering if people had suggestions for power schemes with this type of set up. My main questions regard noise issues. Should I have two seperate transformers, one for digital one from amp? Can I just run dual secondaries? Or can I just use the same secondaries for both boards? Some useful info is that the digital board needs 3.3V and a few (maybe 5) mA. Also as far as shielding the digital board from the analog stuff, any suggestions? I was thinking about making a copper casing. Oh, final question regards ground. Where should the digital and analog ground meet? At the IEC connector? Should they just share a ground? I was thinking that it would be a good idea to have DGND and an AGND, but not sure... Thanks for your time,

Doovieman

[Nuuk]

Excuse my stupidity but what is the digital board for?

[Doovieman]

Originally posted by Nuuk
Excuse my stupidity but what is the digital board for?

Ha, not stupidity at all. The digital board is going to control some extra goodies I'm not exactly sure what will reside on it or what will control it at this moment, but most likley a few leds... Any thoughts from anyone? Thanks,

Doovieman

[tiroth]

If you do not have switching logic (that is, the digital side is not doing anything most of the time) then there is not much need to worry about noise. Star grounding will still help keep any brief noise out of the audio side. I wouldn't worry about separate trafos.

[Doovieman]

Originally posted by tiroth
If you do not have switching logic (that is, the digital side is not doing anything most of the time) then there is not much need to worry about noise. Star grounding will still help keep any brief noise out of the audio side. I wouldn't worry about separate trafos.

Thanks for the note. I'm 99% sure there will be a microcontroller on the board that will constantly be driving LEDs. When you say star grounding, do you recommend two stars, one digital and one analog? If so, where should they meet? If not, where should everything meet? Thanks again for your time.

Doovieman

[BlackDog]

Originally posted by Doovieman



Thanks for the note. I'm 99% sure there will be a microcontroller on the board that will constantly be driving LEDs. When you say star grounding, do you recommend two stars, one digital and one analog? If so, where should they meet? If not, where should everything meet? Thanks again for your time.

Doovieman

I would create a separate ground (doesn't have to be a star configuration) for the digital components, then link that digital ground to your main star ground with a single, appropriately sized, piece of wire....

[Doovieman]

Originally posted by BlackDog



I would create a separate ground (doesn't have to be a star configuration) for the digital components, then link that digital ground to your main star ground with a single, appropriately sized, piece of wire....

Thanks BlackDog. That makes sense. You don't think that I run the risk of getting any ground loops from the digital to the analog if I do that though? Thanks again,

Doovieman

[BlackDog]

You shouldn't get ground loop issues if your wiring from star ground to power supply is thicker than the other ground star wiring....

You should especially ensure that your signal ground wiring is not too thick.....

Think "path of least resistance" from the star point, and you should get the concept !

SteveM

[Doovieman]

Originally posted by BlackDog
You shouldn't get ground loop issues if your wiring from star ground to power supply is thicker than the other ground star wiring....

You should especially ensure that your signal ground wiring is not too thick.....

Think "path of least resistance" from the star point, and you should get the concept !

SteveM

Thanks Steve for your help. I'll report back when I've made progress...for now it's teaching myself how to use this damn microcontroller!

Doovieman