Ground plate under pickup improves tone?

[broadcaster]

Anybody have experience with ground plates?

I heard the early Fender basses had these stock, though the current models do not, do to cost considerations.

Do they improve your tone(say on a Fender P or J?

How does one ground the plate?

Thanks, b

[feojack]

In the October Talk Bass Newsletter, there's an article addressing just this thing, It's basically a "how ti" type of thing. Here is a link to the diagram of it that was published. Maybe you can backtrack & fine the full article:
http://www.talkbass.com/images/tonetip3.gif

Cheers, feo

PS This a copy & paste of the article (Hope it's not some sort of infringment)
3: Tone Tip, with Rodney Gene

Tone tip #3: The greatest P-Bass tone in the world.

Here is another easy mod to help you get great tones and a fresh
sound from your passive bass without major modification.

Ever heard the sound of a telecaster guitar? The bite, twang and
grit of a great telecaster tone are a result of the pickups
construction. Primarily the steel or copper plate underneath the
pickup itself. This plate underneath the pickup has a tremendous
effect on the pickups focus and midrange attack. It increases the
string to magnet focus and literally ‘tightens’ the perceived tone.

However you choose to describe it the tone is down and dirty and
cool.

The original P-bass pickups (not the single coil P-bass pickups)
actually used this same technique in the beginning. Look at any
original P-bass pickup and you will see it resting atop a copper
plate. That plate is a big part of it’s thick focused sound.

The idea of putting a thin piece of ferrous metal underneath a
guitar pickup isn’t new a usual, but you rarely see it on the bass
which is where it would do the most good and have the most
benefit. Even P-Bass pickups these days don’t come equipped with
the plate primarily due to cost, not for it’s lack of benefit. This
‘mod’ however is very effective in reducing mud and getting a
cool funky attack out of your pickups, any pickups.

The idea is equally effective on J-bass pickups or any passive
pickup with exposed poles.

Here is how you do it:

You can pick up a sheet of 16-20-gauge steel at most hardware
stores for only a couple of dollars. The only tricky part of this mod
is actually cutting the steel. I recommend having it done at a local
metal shop, as they will be able to do it fast and cheap.

Trace the pickups pattern on the sheet (Remember that this plate is
going to need to fit in the pickups cavity) and keep your tracing
tight.

Once the metal has been cut, you can simply ‘stick’ it to the
bottom. The magnets from the pickups will keep the plate on there
tight. You must remember to ‘ground’ the plate by soldering a
ground wire to it.
Some players would expect you to have to wax pot the pickup
(with the plate attached) afterward but this is not the case. The
‘unpotted’ plate on the bottom provides additional harmonics,
which adds to the tone. These additional overtones would be
eliminated if potted.

Here is a simple diagram. Good luck!

http://www.talkbass.com/images/tonetip3.gif
~~~~~~~~~~~~~~~~~~~~~~~~
Rodney Gene is a professional bassist in Southern CA
and a hired tone technician and consultant

[broadcaster]

thanks feojack for the reply. has anyone here done this mod to their bass?

[brock29609]

I've had gread success taking out the ground plates and coating the entire cavity (pickup and control cavities) with shielding paint from stewmac.com. Takes out all the noise. All you have to do is make sure the paint is connected to ground. One can of paint is enough for about 5-10 basses/guitars.

[LarryPlayfair]

Does anyone know how you'd ground these plates? I want to do this to a J-bass. How would it affect my original wiring?

[Dennis_UK]

The problem is this: first, if you use a steel plate, it will a) change the tone as stated, b) be a real b**ch to solder a wire onto - you will need a HOT iron. Do this away from your Jazz! Second, if you use a brass or copper plate (which is what was on my old P-basses), it will be a doddle to solder on the wire, and will have no effect whatsoever on the tone, at least not due to any magnetic effects. Pickups are magnetic, and brass/copper are not magnetic metals, so will affect the pickup's field not a jot. So the tone guru don't know his physics/chemistry.
The other end of the wire should go to any convenient ground, usually the case of one of the pots, or the outer of the jack.

Primarily the steel or copper plate underneath the
pickup itself. This plate underneath the pickup has a tremendous
effect on the pickups focus and midrange attack. It increases the
string to magnet focus and literally ‘tightens’ the perceived tone.

OK for steel, complete rubbish for copper - it couldn't affect the magnetic field if it's life depended on it, barring some microscopic eddy current effects if it was moving in relation to the pickup. This is why it's a mistake to put a solid brass bridge on a Tele - the surrounding mass of ferrous metal has a marked effect on how the pickup picks up.

[broadcaster]

Dennis_UK, thanks for the insight. I just installed a '62 pup in a P bass. It came with the copper plate. Sounds real good.

Maybe the amount of labor involved for myself to make plates for my J would be in vain?

[tpaul]

So, you're saying that a steel plate under the pickup will change the tone, but is hard to solder wire to; and a copper plate will NOT change the tone.

What, then, is the point of the copper plate and why do so many pickups come with them?

I also thought I had read somewhere that some telecaster pickups came with a tin bottom plate.

Could someone please enlighten me as to what affect, if any, these various metals will have and what the differences are?

Thanks!

[broadcaster]

"Could someone please enlighten me as to what affect, if any, these various metals will have and what the differences are?"


This is the million $ question, fellow bassists. :?

[Bob Rogers]

A copper plate will act as a shield since it is a good conductor. It is not magnetic, so it won't effect the magnetic field of the pickups. So copper kills noise but doesn't effect the tone.

Steel (or any other magnetic material) will effect the magnetic field, so this could have an effect on tone. You will have to experiment to figure out how. Essentially you are redesigning the pickup. But it is cheap and easily reversible.

The fact that the author of the article is convinced that a copper plate makes a big difference in the tone is an indication of how small the differences in tone are.

[Bluesbob]

came with the copper plate. I installed them in a 60's classic J-bass making sure the grounds were all solid, including the wire to the bridgeplate and the copper strap off the bridge pup to underneath the bridge. I was actually quite pleased with how quiet the bass became, compared to the originals. The pups are kind of hi-fi compared to my '71, so the extra quieting helps little details like finger attack to be heard.

[tpaul]

Maybe I'll repost this over at the pickup section, see if anyone there has more info on how various metals could change tone.