Solder all grounds to bridge, optional?

[jakeac5253]

My guitar was soldered stock with all commons to the neck pot. Is the 'solder all grounds to bridge pot' more of a guideline or are there actual reasons for it being to the bridge pot specifically? Would I gain anything by moving all grounds to the bridge pot or is it more important that they be all in one location?

[David Schwab]

No. The standard way of daisy chaining the grounds from the back of one pot to the next works fine. The whole idea of star grounding is supposed to be to eliminate ground loops, but they can't occur in a guitar anyway, since it only has one ground, at the output jack/amp.

Just make sure you have solid ground connections and you will be fine.

[jrfrond]

You didn't say what guitar you had, but all pots should be grounded either via their bushings, which should be mounted to some sort of conductive backplane such as foil, aluminum or brass sheet, or a buss wire that is soldered to all of the pot cases. Personally, I ALWAYS use the buss wire technique, just in case a pot works loose. Don't trust a metal mounting plate. These mechanical ground connections can also build up resistance with age. I've seen this happen with bridge ground wires as well.

[jakeac5253]

It's a Jackson RR3

[David Schwab]

Personally, I ALWAYS use the buss wire technique, just in case a pot works loose. Don't trust a metal mounting plate. These mechanical ground connections can also build up resistance with age. I've seen this happen with bridge ground wires as well.

I just said the same thing over at TalkBass. People seem to get paranoid about nonexistent ground loops, and they compromise their ground connections.

[David Schwab]

It's a Jackson RR3

I have one here at the moment. I think it's just the way they do things at Jackson. You don't have to solder al the grounds to the one pot, but make sure all the pots are connected together.

[jakeac5253]

I have one here at the moment. I think it's just the way they do things at Jackson. You don't have to solder al the grounds to the one pot, but make sure all the pots are connected together.

Do you think that I should try to line the bottom of the pickguard?

[R.G.]

Do you think that I should try to line the bottom of the pickguard?

Yes, but you should already have done that as part of the shielding needed on the cavity of every guitar. Copper tape is really, really good for this.

For the life of me, I can't understand why every cavity cover and cavity is not already covered with a metal shielding coating.

But that would be taking money away from the guitar techs.

[David Schwab]

For the life of me, I can't understand why every cavity cover and cavity is not already covered with a metal shielding coating.

I agree, and I can't understand why Fender pickups still come with that unshielded cloth covered wire. No shilding in the pickups, no shielding in the guitar (save a small piece of aluminum foil), and no shielded cable. Oh yeah, and single coils!

In one of the bands I play in the guitarist's Strat hums so bad when he's using a lot of overdrive that you almost can't hear the notes!

[Steve Conner]

Strat pickups come with unshielded wire because the single coil already picks up so much hum that shielding the wire would be pointless.

[jrfrond]

I agree, and I can't understand why Fender pickups still come with that unshielded cloth covered wire. No shilding in the pickups, no shielding in the guitar (save a small piece of aluminum foil), and no shielded cable. Oh yeah, and single coils!

In one of the bands I play in the guitarist's Strat hums so bad when he's using a lot of overdrive that you almost can't hear the notes!

That's actually not true Dave. They ARE shielded, just poorly. The cavities are painted with carbon conductive paint prior to the finish coat (!), and the pickguard is foil-backed in the control area. The finish in the cavity is scraped at one point in the cavity bottom, and a solder lug with a ground wire is screwed to that point.

Like I said, poorly.

The whole single-coil thing is a multi-pronged issue. You could totally enclosed SC's in copper foil (think of old Alembic pickups) for ELECTROSTATIC shielding but it will do NOTHING for ELECTROMAGNETIC shielding, and THAT is one of the big issues. You can REDUCE the noise a bit by doing this, but never eliminate it, hence the need for the RW/RP pickup combos we see now on SC guitars. However, not EVERYONE wants "that" sound. In order to fully shield a SC pickup, you'd need to wrap it in Mu-Metal, but then you'd block the magnetic field from the strings.

Lace sensors use a Radiant-Field Barrier system that shields the coil from a lot of EMI/RFI and reduces noise, but does NOT eliminate it.

The Alembic system using a differential preamp with low-Z pickups and making use of common-mode rejection with a balanced low-Z instrumentation amplifier works flawlessly, but not everyone wants active electronics. Ditto for EMG.

Because we live in an RFI/EMI-polluted world, it is virtual insanity to NOT use hum-cancelling pickups if you are going to be working in medium or high-gain settings. There are enough great hum-cancelling SC designs to not have to put up with the sonic noise assault. Ironically, this is NOT as much of a problem on concert stages because of the distance the guitars are from localized noise sources. However, whatever is airborne is still there no matter what.

[Mike Sulzer]

For really strong electric fields, even complete shielding fails. When shielding cancels the electric field, a current flows from ground into the shield. This is how it works; charge is distributed on the shield to cancel the field. For an ac field this means that a current is continuously flowing along the shield of the guitar cable to provide the time-varying charge to the shield. Thus, there is a voltage drop along the cable shield, and this appears in series with the input signal (since there is no separate ground wire for the signal ground).

This effect is not normally a problem, but you can see how it could be if you have a bad connection. Or if you have worked hard to get rid of everything else and then encounter an unusually strong field.

[David Schwab]

Strat pickups come with unshielded wire because the single coil already picks up so much hum that shielding the wire would be pointless.

This is true!

[David Schwab]

That's actually not true Dave. They ARE shielded, just poorly. The cavities are painted with carbon conductive paint prior to the finish coat (!), and the pickguard is foil-backed in the control area. The finish in the cavity is scraped at one point in the cavity bottom, and a solder lug with a ground wire is screwed to that point.

Like I said, poorly.

Well I did allude to the foil on the pickguard, and of course older Strats had the big aluminum shield under the pickguard, but I meant the pickups are not shielded at all.

I've seen plenty of these guitars with the conductive paint shielding that is not even grounded. The Jaguar basses have a real issue with ungrounded shielding.

Yeah, poorly.

The whole single-coil thing is a multi-pronged issue. You could totally enclosed SC's in copper foil (think of old Alembic pickups) for ELECTROSTATIC shielding but it will do NOTHING for ELECTROMAGNETIC shielding, and THAT is one of the big issues. You can REDUCE the noise a bit by doing this, but never eliminate it, hence the need for the RW/RP pickup combos we see now on SC guitars. However, not EVERYONE wants "that" sound. In order to fully shield a SC pickup, you'd need to wrap it in Mu-Metal, but then you'd block the magnetic field from the strings.

I agree. There are pretty good hum canceling Strat pickups out there days.

Lace sensors use a Radiant-Field Barrier system that shields the coil from a lot of EMI/RFI and reduces noise, but does NOT eliminate it.

I have a Lace Sensor from a Stat someone gave me in one of my guitars, and I'm quite surprised how quiet it is. They are very odd pickups, at least from the way they are made.

The Alembic system using a differential preamp with low-Z pickups and making use of common-mode rejection with a balanced low-Z instrumentation amplifier works flawlessly, but not everyone wants active electronics. Ditto for EMG.

Right. The newer Alembic AYX pickups are stacks with both coils wired in series. The top coil has the magnets and the bottom just has a plastic core. Then they enclosed the assembly in copper mesh. They are surprisingly low output for a 9K pickup.

Because we live in an RFI/EMI-polluted world, it is virtual insanity to NOT use hum-cancelling pickups if you are going to be working in medium or high-gain settings. There are enough great hum-cancelling SC designs to not have to put up with the sonic noise assault. Ironically, this is NOT as much of a problem on concert stages because of the distance the guitars are from localized noise sources. However, whatever is airborne is still there no matter what.

Agreed.

[KickAxeUSA]

jakeac.......Also make sure that the bridge has some sort of ground wire from it to the daisy chain of pot grounds. I have replaced alot of older strat pups with the DiMarzio noiseless ones and have had great success with no or very very little noise, making sure we give the old pups to the customer so if there is a time that it is sold, it can be restored back to OE classic. Also installed some tone shappers into strat types and those are pretty nice units. You can change the pot values, cap values, and pot assignments with the flick of a switch........SWEET. Still have to remove the pickguard though......unless you cut out a spot in the back of the guitar to access the tone shapper