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Star grounding + U Retro = p/u lead to board or ground?

Discussion in 'Pickups & Electronics [BG]' started by Rodent, Jul 11, 2005.


  1. Rodent

    Rodent Supporting Member Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Regenerate Guitar Works
    I'm setting-up a U Retro in bass where I utilize star grounding to a common ground lug. Normally, with all of the other pre-amps I've installed (or when set-up passive), all of my p/u ground leads would be connected to a grounded star washer and not the actual pot istelf.

    But the set-up for a U Retro is a little different, as each p/u has its own dedicated hot/ground post right on the pre-amp board. (Reference diagram here, then select Products + U Retro 01 Deluxe + Installation)

    Two questions:

    • Can I send the ground lead for each p/u to the common ground washer instead of the individual p/u ground terminal?

    • If the above answer is yes, can I still connect the passive tone control as per the included diagram?

    My concern is that I may somehow damage the board or enable a ground loop by utilizing a common ground for the p/u leads.

    TIA for any assistance!

    R
     
  2. sgt.floyd

    sgt.floyd

    Dec 5, 2004
    basston
    I don't know the specific answer to your question- but I can tell you what I did w/ mine.

    I wired a U retro delux that had an additional blend pot- My bass has 2 LP pickups and a piezo pickup. The extra blend pot mixes the LP's and the stock blend mixes the output of the LP's and the Piezo- so the way I wired the LP's- they had 2 wires out of each and an outer sheath conductor (for sheilding I assume)- so that said- the 2 wires out of each pickup went to the blend pot- then to the screw lugs on the U retro board and the outer sheilding went to the star ground. The passive tone was wired as per spec. If memory serves, I checked it w/ an Ohm meter and all the grounds were common anyway, so it probably won't matter.

    When I first did it, I didn't ground the pots, and it all worked, but there was a pretty bad hum. I had been trading e-mails w/ John East, so I asked him about it and that's when he told me the need for the star ground and how to do it. I just made sure all the pots were connected via a copper sheet and that cleared it up. It's been perfect ever since!

    If you're worried about it, I'd drop John a quick email- he was really great- answering all my questions right away (no matter how stupid like "what's a star ground?" ) and making sure it was all working as it was supposed to- truly top notch! I wish everyone stood by their products like he does.

    I hope that helps-
     
  3. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Memphis
    Yes, but there's not much point with this design. You'd still have to run wires from the common ground point to the p/u ground points on the U Retro terminal.

    Well, your link is bad, so I can't see the diagram, but as long as the passive tone control is connected to ground (be it the U Retro or the common ground point) it will work fine.

    Nope and nope. BTW, you'll need to ground all the individual pots. If using a control plate, it's taken care of. IF there is no control plate, use copper shielding foil (connected to ground) on the inside of the cavity so each pot is secured against the foil.
     
  4. Rodent

    Rodent Supporting Member Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Regenerate Guitar Works
    Had a little copy/paste error in my link. It's been fixed.

    Thanks for the feedback so far.

    R