Question about the tone-tip (Talkbass newsletter Sat, 25 Oct 2003)

Discussion in 'Pickups & Electronics [BG]' started by My bass in your, Nov 6, 2003.

  1. My bass in your

    My bass in your

    Nov 1, 2003

    I'm planing to do this mod. Read below.
    My crappy P-bass copy (Charvette) needs a better tone and I don't have money for a new PU.

    My question:
    My PU is covered, no exposed poles, BUT I can see a block of magnet on the under side. Can I do this mod with good results?

    Well, maybe it's better for me to save up for some EMG'z.. but for now I'd be nice.

    Thanks and greetings from The Netherlands!

    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

    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

    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!
  2. marc40a


    Mar 20, 2002
    Boston MA
    That's a tough call.

    I play a couple of P's... One w/ the plate one w/out. While they both have different tones, I'm more likely to believe that it's because the PU's are different (also different weight bodies, necks, etc...)

    The point that is misleading in the article is that he's implying that the PU magnet and copper shield touch. They don't. The copper has foam on top of it to cushion the PU and allow height adjustment.

    I don't know... I'll entertain the thought that the adjacent(not touching) copper plate maybe affects the magnetic field. I have a hard time thinking it would be perceivable...maybe but I doubt it. The logic of the article is flawed and sounds more like voodoo than science or physics.
  3. I dunno. I've heard of the plate thing before, but thats it, head of it. It will change the magnetic field around, that much I know.

    I have really no idea exactly how sticking various metals and stuff around magnets changes the field, except that if you do it some ways it focuses it, otherways it disperses it and stuff. Somebody? Or would I be right in saying that nobody really knows, they just guess and trial and error the answers?

    Back to the question, my advice: give it a try. It sounds pretty cheap, and easy to A/B test as well, cause you've got jack all in the way of real modifications to do. Would it even need to be grounded? Cause if you do it like Marc said, its not actually in contact with any of the circuitry?

    Josh D
  4. My bass in your

    My bass in your

    Nov 1, 2003
    Thanks for the input!

    Now I know how it should be installed, but now I'm also a bit sceptic. There is no real proof that it works... BTW: yes, it needs to be grounded.

    Jazz ad told me that his PU of his old Ibanez Roadstar 2 had a copper plate under the PU. Stock. Now another Harmony Central forumite has it and is very content with the tone of the PU.

    The mod isn't very expensive, but it may take some time. And considering that the P-bass and the PU aren't good enough to improve. Like, a bit crappy, I think I go for active EMG'z! Christmas is comming and then I'm sure that the sound will improve. Installed on a baseball bat? Still sounds like EMG. :D

    Thanks again!
  5. There is proof that it works, just how much it works is the question. Certain metals (ones the exhibit diamagnetic properties) exlude (push away) a magnetic field. This will happen with the plate but with its dimensions its a little harder to anticipate where the field will go, but you'll end up with a stronger magnetic field at the pup (I think), so it'll sound different.

    I think that ferromagnetic metals may draw the field in a bit possibly. I'm just guessing there. I'm doing a little reading from my Materials Eng book, wish I'd got the Physics book that I also need for the course.

    Its up to you whether you do it, I got some hols coming up, might take it for a spin. Try them out with the soapbars as well.

    Can you tell me why it needs to be grounded? I thought that because it wouldn't be in contact with any part of the circuit it wouldn't need grounding?

    Josh D
  6. Bump. In particular refering to my last quesion, does it need to be grounded? Why/why not?I'm on holidays now, rotting my mind, so I wanna do some easy stuff for cheap.

    Josh D
  7. marc40a


    Mar 20, 2002
    Boston MA
    It definitely needs to be grounded.

    I'm not engineer by any stretch but I think maybe a layman's answer to "why?" is because it's too close to the magnetic field and will pick up electromagnetic interference or RFI.

    Even a jazz bass control plate will pick up interference if not grounded, same with static crackles from metal knobs if the they're not grounded. Even strings pick up interference.

    That doesn't necessarily mean that because the plate affects the magnetic field that it will have a perceivable effect on 'tone.' Like I said before, I'll entertain the possibility but I'm definitely a skeptic.
  8. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    Here's a photo of the back of a Seymour Duncan SJB-5b pickup, you can see the foil is grounded.

  9. But, if its not part of the circuit (using it like Marc said, on the other side of the foam) and it picks up interference, its not going to transfer it anywhere. Maybe?

    If you guys are right (probly the case), I'm missing something about how the electronics work, and are related. I can take it that it will pick up interference (its metal, that happens) but where will it go if its not connected to anything (or should I be asking how its transferred)? Is it something to do with why the sheilding in the cavity needs to be grounded? I think I almost understand but theres still something I don't quite get.

    I'm sorry if I'm coming across disrespectful, I value all your info, I just wanna know why.

    Josh D