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Greasebucket Tone Circuit

Discussion in 'Pickups & Electronics [BG]' started by SasquatchDude, Jul 19, 2012.


  1. Hi all:

    Could somebody please tell me how to go about replacing the Greasebucket tone circuit in my American Special Jazz with the regular tone pot found in the American Standard series?

    I was a complete newbie when I started playing last year, and with the advice of friends, I grabbed the cheapest American model I could find. As my own style and taste has developed, I've really come to dislike the Greasebucket. While Fender boasts "rolling off highs without adding bass", I don't like the effect – if I roll off on the tone, I want to get a thick, muddy, bassy tone. Quite frankly, I'm actually after that heavier, fatter P-Bass sound, though I had no way of knowing this when I made my purchase.

    I'm also considering dropping in a set of DiMarzio Model Js – any thoughts on that?

    Anyhow, thanks for bearing with me during my first post.
     
  2. tastybasslines

    tastybasslines Banned

    May 9, 2010
    Los Angeles, CA
    I'm interested too...my Highway One P is great, but hate the grease bucket. I was thinking about putting a Bill Lawrence P in there too as the pu is the same as the mexi's I believe...can anyone confirm that? Anyway...I've heard that the pots to use are called "orange" I think....I'd like know how to change the circuit properly. Shouldn't be that hard though.
     
  3. If you look at the circuitry under your pick-guards if you have the greasebucket tone circuit there will be resistors and capacitors on the tone side. Normally what the tone knob on a bass does is adjust a filter that shaves off a certain frequency of the sound an amount depending on the amount of resistance from the potentiometer and a frequency dependant on the value of the capacitor.

    The name brand of the components you install will affect the reliability and longevity of the circuits, but not necessarily the sound. The sound is affected by the value of the components (ie. how much resistance or capacitance) and their configuration.

    tastybasslines: you probably were hearing a very common "orange drop cap" which is a popular capacitor used in tone circuits on guitars and basses.

    If you want to get rid of the 'greacebucket' tone circuit I recommend you learn how to solder and change the circuit to something more like this: http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=std_jazz_bass

    If you look up information on the capacitors connected to the tone knob you will find people have preferences on the value, but .05 or 0.47uF (microfarad) is probably the most common. Certain types of capacitors have a better tolerance, which means they will be closer to their advertised capacitance.
     
  4. khutch

    khutch Praise Harp

    Aug 20, 2011
    suburban Chicago
    You can find an illustration of the grease bucket circuit on a Fender diagram here. It is on page 2 if that link does not open directly to page 2. The difference between what you want and what you have is that a normal tone control does not have capacitor 16 or resistor 18 and capacitor 17 is 0.02 uF rather than the more typical 0.047 uF.

    If you want to "degrease" your bass I would remove both caps and the resistor by unsoldering them or simply by clipping their leads off. Then solder a wire between the terminal on the tone pot with the wires attached and the center terminal of the pot. You could also just unsolder both of those wires and then resolder them to the center terminal, either way works exactly the same. Now you solder the capacitor of your choice between the terminal where cap 17 formerly attached and the case of the pot.

    The usual value for the tone cap is 0.047 uF. Instead of removing cap 17 you could solder the lead that formerly attached to resistor 18 to the pot case. This would give you a slightly brighter 0.02 uF tone cap. Or if you removed cap 16 carefully you could reuse it as a darker than normal 0.1 uF tone cap.

    The super quick and dirty way to degrease is this: remove cap 17 and resistor 18 by the method of your choice. Clip the lead of cap 16 that attaches to the pot where the wires do as close to that terminal as possible (leave the lead that attaches to the center terminal attached to the center terminal). Now swing the clipped lead over to the pot case and solder it there. You now have a 0.1 uF tone cap and you also have a tone knob that works backwards of normal. Perhaps you can live with both of those. It is always possible to go back in later to change cap to a different value and/or rewire as noted above to make the tone knob work normally.

    Ken
     
  5. Stealth

    Stealth

    Feb 5, 2008
    Zagreb, Croatia
    If you want an unusual tone control that goes beyond what a regular does, most people have recommended building your own TBX control instead of the Greasebucket.
     
  6. Thanks a lot for the input, everyone.

    If I replaced the 250k tone pot with a 500k while I'm at it, I'd theoretically get a broader range of tone adjustment, correct?
     
  7. tastybasslines

    tastybasslines Banned

    May 9, 2010
    Los Angeles, CA
    Thanks alot guys.

    Khutch... when you say..

    "If you want to "degrease" your bass I would remove both caps and the resistor by unsoldering them or simply by clipping their leads off. Then solder a wire between the terminal on the tone pot with the wires attached and the center terminal of the pot. You could also just unsolder both of those wires and then resolder them to the center terminal, either way works exactly the same. Now you solder the capacitor of your choice between the terminal where cap 17 formerly attached and the case of the pot. "

    Which is the second pot you are referring to?

    Terminal to terminal on the same pot? Or is the second pot the volume pot?

    I have a soldering iron and am ready to make the switch.
     
  8. khutch

    khutch Praise Harp

    Aug 20, 2011
    suburban Chicago
    I'm sorry, I meant terminal to terminal on the same pot, the tone pot. Normally the pickup signal comes in on the center terminal of the tone pot and the tone cap connects to the terminal where the 0.02 uF cap is on the greasebucket. Since the pickup wires on the greasebucket connect to the terminal that is left unused in a standard tone circuit you can save a small amount of work by just connecting that terminal to the center terminal. If you can gently bend the two terminals so they touch you don't need a wire, just solder them together.

    Or you can unsolder the wires from where they are and resolder them to the center terminal, either way works.

    Ken
     
  9. tastybasslines

    tastybasslines Banned

    May 9, 2010
    Los Angeles, CA
    Ok....here goes...got my cap and soldering iron in hand....

    GULP
     
  10. tastybasslines

    tastybasslines Banned

    May 9, 2010
    Los Angeles, CA
    I realized the guy at Radio Shack gave me .0047 instead of .047 so I returned it and got this instead.

    What is 50wvdc mean? This would work?

    s1lus3.
     
  11. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    That will work fine.

    That's "working volts DC" so it's rated for 50 volts.
     
  12. tastybasslines

    tastybasslines Banned

    May 9, 2010
    Los Angeles, CA
    Thanks David. I did it anyway, and figured it would be easy to change if it wasn't right. After reading through a lot of threads...I'm convinced that you don't need anything special and pretty much any cap would work.

    Everything works fine, no noise, all good...HOWEVER - the tone is now reversed on the pot. If I dial it clockwise, it removes the highs and counter clockwise makes it brighter. I'm used to it being the reverse. And, the GB worked that way too...Did I go wrong somewhere? What caused this?

    Anyway...Here is pre and post change I just did right now. I used this diagram.

    Before, with the 2 caps and resistor on the tone pot:

    dqiw68.

    After:

    2namzcp.
     
  13. khutch

    khutch Praise Harp

    Aug 20, 2011
    suburban Chicago
    You can fix that by moving the white wire from the volume pot to the other outer lead of the tone pot.

    Ken
     
  14. tastybasslines

    tastybasslines Banned

    May 9, 2010
    Los Angeles, CA
    The little jumper wire? So just move it from the left terminal of the tone pot to the unoccupied one on the right?

    Why does that reverse the control?
     
  15. khutch

    khutch Praise Harp

    Aug 20, 2011
    suburban Chicago
    Yep, that is all you have to do.

    When you turn the pot shaft CW the resistance between the center and right terminal increases while the resistance between the center terminal and the left terminal decreases. If you want the tone to become brighter when you turn the shaft CW then you connect to the center and right terminals because the increasing resistance will make the tone cap have less effect. Normally the wire goes to the center terminal and the cap to the right but this makes no difference whatsoever so you can just move the wire.

    Now it might seem that what I say above is backwards when you stare at the picture you took and think about what is going on. But you have to remember that what looks like CW in that photo is CCW when you turn the pickguard/control plate over and look at the pot from the knob end of the shaft.

    Ken
     
  16. Darko74

    Darko74

    May 18, 2007
    Dublin, Ireland
    some guy on here. put in a push pull knob that switched between greace bucket and the standard. i Pmd him about but havnt tried it myself yet. heres what he replied to me.

    "IIRC Basically you use the pushpull like a toggle switch pickup selector to swap the path through one or the other cap. You solder a wire from the lug on the tone pot that the cap usually connects to onto the common tab of the switch (the middle one) then solder the greese bucket caps from the top lug of the switch to the ground (back of the tone pot) and another cap (whatever value you desire) from the bottom lug to the ground (back of the pot) that way when the pot is down you have the 2nd cap and when you pull it up it'll swap caps to the greese bucket (or greese bucket at the bottom other cap at the top if you wnat to reverse the push pull and have greese bucket as the down tone crontrol)"
     
  17. tastybasslines

    tastybasslines Banned

    May 9, 2010
    Los Angeles, CA
    Thanks Khutch. Everything worked out.

    For anyone who needs the proper diagram...this is it, if you want brighter tone while moving the tone pot forward.

    This is a standard Greasebucket tone changed to a Standard P tone control. The Seymore Duncan diagram above works, but it does not face the tone control in the proper direction.

    2yv9o2b.
     
  18. Marial

    Marial weapons-grade plum

    Apr 8, 2011
    What would be the best way to get a warmer, more buttery, tone out of a Hwy 1? Pick ups? I don't know if the grease bucket is the issue for me. I just can't seem to get a smooth sound out of the E string. Brighter isn't what I'm after...
     
  19. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    What kind of strings are you using?
     
  20. Marial

    Marial weapons-grade plum

    Apr 8, 2011
    I've tried a number of brands over the years, from the nickel XLs, to Pressurewounds, to both Chromes and TI flats. Thus far DR Sunbeams have given me the closest tone to what I'm really after: warmth with clarity. There is a sweet period after they break in and loose the initial crispy top end where I can get really close to the buttery tone I'm after, but I find the E string a little ill-defined in comparison to the rest of the strings.

    The bass is completely bone stock, including the BAII bridge. It has a rosewood fingerboard. In order to keep the tone mellow I usually have both volume knobs backed off a quarter to halfway and the tone knob rolled all the way or 3/4 off. I only up it if the song calls for a more trebly attack.
     

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