Ground issues

[philbinator1]

Hi everyone,

I'm having some loud hum problems with my builds, I think it's ground related.  I hear a lot of things about how to
ground, seperate grounding points for each ground, "Star" grounding (what is that?)...can anyone point me in the
right direction here please?

thanks   

[MikeH]

There's lots of info in the wiki on this, I think.

Basically star ground is all grounds tied to one single point (Like a star!), usually the input jack, as opposed to having them connected in a 'string' or 'line' if you will, which I believe is called 'tree' grounding.  Star grounding is the quietest because it doesn't allow for stray paths for electrons (read: ground loops), like through an enclosure for instance.  For the quietest grounding, you should use all isolated jacks, star grounding, and then connect the ground star to the enclosure at a single point.  Totally overkill in a stompbox, sometimes necessary in amplifiers.

[philbinator1]

There's lots of info in the wiki on this, I think.

Basically star ground is all grounds tied to one single point (Like a star!), usually the input jack, as opposed to having them connected in a 'string' or 'line' if you will, which I believe is called 'tree' grounding.  Star grounding is the quietest because it doesn't allow for stray paths for electrons (read: ground loops), like through an enclosure for instance.  For the quietest grounding, you should use all isolated jacks, star grounding, and then connect the ground star to the enclosure at a single point.  Totally overkill in a stompbox, sometimes necessary in amplifiers.

Thanks for the reply mate!     So, by isolated jacks, you mean the ones with a plastic washer that can't make contact with the enclosure?  How do you um...configure the star?  Just join all the wires together (the star shape you mention) then solder to enclosure? 

You see, I made a fuzz for a mate, and when he daisy chains it with his other pedals it hums like a mofo.  I have 2 or 3 different ground points in that box, with un-isolated jacks...?

[MikeH]

There's lots of info in the wiki on this, I think.

Basically star ground is all grounds tied to one single point (Like a star!), usually the input jack, as opposed to having them connected in a 'string' or 'line' if you will, which I believe is called 'tree' grounding.  Star grounding is the quietest because it doesn't allow for stray paths for electrons (read: ground loops), like through an enclosure for instance.  For the quietest grounding, you should use all isolated jacks, star grounding, and then connect the ground star to the enclosure at a single point.  Totally overkill in a stompbox, sometimes necessary in amplifiers.

Thanks for the reply mate!     So, by isolated jacks, you mean the ones with a plastic washer that can't make contact with the enclosure?  How do you um...configure the star?  Just join all the wires together (the star shape you mention) then solder to enclosure? 

You see, I made a fuzz for a mate, and when he daisy chains it with his other pedals it hums like a mofo.  I have 2 or 3 different ground points in that box, with un-isolated jacks...?

Yes to both of your first questions. 

As far as the paedal goes, Yes- I'd make sure you don't have any ground loops.  Do you have a PS filter cap in the pedal?  That would be a largish electrolytic (100-470uf) across the 9v+ and ground.  Also see if it hums on it's own; it might be picking up noise from his other pedals.  Or it might just be noisy because it has a lot of gain.