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(bridge) Grounding Question

Discussion in 'Pickups & Electronics [BG]' started by catphish, Jul 22, 2003.


  1. catphish

    catphish

    Feb 25, 2003
    Okay, I'm swapping all the EMG electronics in my quantum for a NTMB Bartolini pre amp and MC45 pickups. I got all the parts, and a lot of advice, from Jack Read (what a nice fellow). He says that 99% of basses have a bridge ground. I had never even heard of one before, and I've been doing a fair amount of reading up on it. He said I can try it with out, and see if it hums, or run a thin copper wire outside the body so I don't have to drill, which I think is silly. If I decide I need a ground wire I'll drill a hole for it. So do you know if a bridge ground is really necessary? Should I bother trying it without one, or just bite the bullet and drill for it.
     
  2. Running a wire outside for testing purposes is the easiest way to rapidly A/B the idea under differing conditions.
     
  3. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Maryland
    Owner: FBB Bass Works
    Wire it up, see if it hums, run the wire outside, see if it stops. I put a bridge ground on all of my basses unless I am putting in EMGs or Alembic pickups.

    I dunno what Modulus does, but I always drill the hole for a bridge ground whether I am using EMGs or not. They produce a lot of basses with different kinds of pickups, so the hole might already be there.
     
  4. catphish

    catphish

    Feb 25, 2003
    Yeah, I had the same thought and checked that last night. No luck; my bass came stck with EMGs. It's a '93 neck through, and I have to say that in general the cavity was pretty sketchy looking. I'm going to dress it up with copper sheilding while I do all this.

    I'll just add the ground, it can't hurt. I guess I'll just drill a .055 hole from under the bridge into the cavity. Then run a tiny wire from the bridge to my ground.
     
  5. geshel

    geshel

    Oct 2, 2001
    Seattle
    Not entirely so - if you touch a hot mic or piece of equipment (hot meaning has a voltage on it, usually from being improperly grounded and/or a loose wire inside the equipment is touching the case), you're better off not being grounded yourself (because you don't want to present yourself as an easy path for that current to take). If the bridge is grounded and you're touching the strings, you're grounded too. As has been pointed out, most basses have the bridge grounded anyway, so this is nothing new. But, you're slightly safer if your strings aren't grounded.
     
  6. catphish

    catphish

    Feb 25, 2003
    I've heard this debated in the course of my research and frankly I'm not entirely sure what I believe regarding the safety concern. But many people do share your views. Besides, whats to keep you from coming into contact with it else where, such as a toggle switch. Regardless, the fact that most basses have it is the most swaying fact for me. Besides, you should always check the ground before you plug into a venue anyway, right?
     
  7. geshel

    geshel

    Oct 2, 2001
    Seattle
    Well - it's an issue that has been known to cause severe flame wars, and I have no idea why. First, the facts are undebatable: you, as a human, are better off being as un-grounded as you can be in almost any situation involving mains-powered equipment. You're right, you may still touch the plug or a metal knob or something - but you're far likelier to be touching the strings, as you're playing them and all. And you should always check your equipment out - but everyone's run across a hot mic on some venue's stage at some point. So, my POV: if there is no reason to ground the strings (bass is quiet enough without using you as a ground plane), then don't.

    It's not a big thing - just a point I don't think many people quite understand.
     
  8. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Maryland
    Owner: FBB Bass Works
    I put a 220Kohm resistor in parallel with a .001mFd cap inline with the bridge ground. This thing is supposed to act like a fuse and break the ground if too much current hits it. You lose a bit of the noise reduction, I think, but well worth it if there is a chance of shock.
     
  9. It's either zzounds or MF that's selling an instrument cable with some kind of protection in it.
     
  10. catphish

    catphish

    Feb 25, 2003
    Well, I went for it last night and drilled the hole for the bridge ground. I ended up needing to use a 3/32nd drill, because I couldn't find a .052 drill long enough. I drilled into the side of one of the bridge mounting screws so I didn't have to add a new hole in the face. It turned out well. I also did all the copper shielding in the cavity. I'll post pictures of it all when the projectis completed.
     
  11. zombywoof5050

    zombywoof5050

    Dec 20, 2001
    Don't use a tiny wire, it may not help and may even make it worse.

    On my stack-knob RI Jazz (no grounding channel, only a strip from bridge to bridge pickup), I put some EMG's and a BTC circuit in it and was happy that I didn't have to drill a channel for a ground.
    When I got tired of the EMG's, I decided to put the original pickups back in but with a VVT instead of stack-knob (stack knobs and original grounding strips and plates long gone), so I had to drill a channel from the bridge to the control cavity. I drilled a small hole and used a very small solid wire and soldered it onto one of the grounds on one of the pots. It was noisy as hell and didn't help at all, even made it worse! When I touched the metal control plate that the pots are mounted onto, the noise stopped, so I knew it was an insufficient ground. I redrilled a bigger hole and got a nice big thick ground wire and wrapped it under one of the pots between the pot and metal control cavity plate and the noise went away.

    Moral: If you just use a tiny wire, it may not work well at all.