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P/J wiring with two pots

Discussion in 'Pickups & Electronics [BG]' started by P-punk, Oct 6, 2013.

  1. I know the topic has been covered before, but I couldn't find the excact answers I was looking for, so please bear with me.

    After years of hunting and trying and failing, I finally found the perfect bass for me earlier this year. It is a kind of mix & match bass with a 1968 Jazz Bass neck, body, pickup and electronics from a 1978 Precision, and hardware from god knows where.

    (A crap cell phone pic, but it was the only one I had right now).

    After I bought it I also changed the pups to some '70s DiMarzio, and strung it with LaBella flats. It is now (almost) the bass of my dreams. It looks good, it plays good, it sounds good - it just needs a little bit more "bite".

    That's why I've decided to add a DiMarzio model J at the bridge. However I'm not decided on how to wire it, as I don't want more than two pots.

    I am therefore thinking of having a concentric master volume/master tone (as the'62 Jazz) and a blend pot.

    Is this a good idea, or a stupid idea? Is it a better way to do it? What would you do, and why? All help is heartly appreciated.
  2. I know a lot of people have added a J-pup in the bridge position. How did you do it? What controls did you choose and why?

    I'm still undecided on what the best sollution would be.
  3. DWBass

    DWBass The Funkfather

    I modded a P Bass last year. I had my tech install active EMG P & J pups. Then added a concentric Volume/Volume (EMG) and a BTC (concentric Bass/Treble)(EMG).
  4. Matthijs


    Jul 3, 2006
    That would be a perfectly good idea, depending on how you wire the blend and what the pot values are.

    A good way is to wire the blend without connecting it to the ground. That way the blend doesn't add to the overall impedance of the circuit. And then you can keep the values on the vol/tone stack close to the original.
  5. pbassnut

    pbassnut Supporting Member

    Sep 27, 2004
    Falls Church, VA
    I would personally leave your FrankenP as is and go with some brighter sounding strings if you want more bite. Those old 70's DiMarzio Model P pickups are really great sounding pickups and are highly sought after and adding a DiMarzio Model J in the bridge position will only degrade the sound because of the pickup loading effect it will add and will also diminish your midrange response when you mix in the J pickup because of phase cancellation. I recently pulled a DiMarzio Model P pickup out of a P/J configured bass (with a DiMarzio Model J just as you are proposing to do) and was surprised at how much better the Model P pickup sounded by itself in a P pickup only configured bass compared to how it sounded as part of a P/J circuit.

    LaBella flats are thud city all the way (which is a good thing if you're a blues player like me). However, if you want a brighter sound (and want to stick with flats), you might try the new Fender flats ( http://www.amazon.com/Fender-Access...r=8-10&keywords=fender+flatwound+bass+strings ) which are brighter sounding than the LaBella flats and are relatively low tension which would be good for your old Jazz neck.
  6. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    I would do a V/V/T set up with a stacked volume pot.
  7. Thank you everybody for all the help so far. If someone have some schematics showing how they would do it, I would be very happy. I won't do the job myself. I will have my luthier do it for me, but he's more of a guitar guy than a bass guy, so I prefer to come to him with a detailed plan on how I would like it. :cool:

    pbassnut - Are you saying that the soloed P-pup would not sound as good as it does now? Is there a way to wire the P7J-setup so that this won't happen?

    Nah. I already have a P-bass with rounds. This is my flatwound P. I have to disagree that LaBellas are thud city. Maybe the Jamerson set, but I'm using the FS set (43-104) and they're not "all thud". Tensionwise they're not as bad either. Just a little bit higher tension than the Sunbeams I have on the other P.

    EDIT: I recently sold my 1971 Jazz, which I also had strung with LaBella flats. I kinda miss the sound of the bridge pickup, and that's the reason why I wanna add a pickup on my P.
  8. Fawkesguy

    Fawkesguy The sea refuses no river.

    Mar 5, 2005
  9. Bassdirty


    Jul 23, 2010
    THAT is sweet.

    Hmm.. I wonder ..is there anyway to put in a switch so that I could hit the switch, and have the J shut off completely( to run the P solo), and then flip the switch the other way and have the J come on ..to about 80% volume when I run them together..(I never solo the bridge PU. :scowl:).
    That way I can still rock my P tone all alone..without the pesky J suckin my tone off. (to be honest I never really noticed that it [J pu] "takes away" form my P tone, but I do read alot about it here on TB)
  10. Wow. What an incredible cool bass!

    You have a valid point about the tone control. I never use it during shows. I sometimes use it while practicing. When I'm playing shows, I usually just set the tone on the amp and have both volume and tone on full on the bass. :bassist:

  11. Fawkesguy

    Fawkesguy The sea refuses no river.

    Mar 5, 2005
    Thank you. I love her. :D

    I think just turning the J down all the way would negate the need for a kill switch. I don't notice any "tone suck" from the J pickup.

    On a semi-related note - I made sure to order a 5% overwound J to make sure its output would be closer to that of the P pickup, or at least to help it "contribute" more. With both pickups on full, I feel that it makes for a more full, complex sound. Both pickups are Lindy Fralins.
  12. TomB

    TomB Supporting Member

    Aug 24, 2007
    I think you can find wiring schematics for G&L SB-2's on this site, both the stock (2-knob) PJ & also a tone mod done using stacked knobs to replace one of the two knobs. A Fender could be wired the same ways, I'm sure. Personally, I'm perfectly happy with the SB-2's standard two volume knobs, 1 for each pickup, roll the bridge up as needed for bite. Like others, I've no use for a tone control anyway ...would just leave it wide open if I had one. I guess that must have been what Leo was thinking when he designed the SB-2 (and then redesigned it, still with 2 knobs).
  13. ctmullins

    ctmullins fueled by beer and coconut Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    Stacked vol/tone and a 3-way switch.

    Or screw the tone control and do vol/vol, or vol/3-way. That's how I roll in passive-land.
  14. packhowitzer

    packhowitzer 155mm of pure destruction

    Apr 20, 2011
    I'm no expert, but i think just having the other pickup in the circuit at all changes the sound to some degree (whether it is audible to you is of course unique to you.)

    I think that is the issue that some people have with the p/j config with a blend knob- even when you roll the knob all the way to the P pickup- it still doesn't sound exactly like it would if there was just the single p pickup. there will always be some minor amount of "scoop".

    I wasn't totally aware of this phenomenon before i joined TB, but i will say that i have a stingray H (with a single humbucker) and a stingray HH (with two) and the HH bridge pickup soloed doesn't have quite the same sound as the H. I know that's just an anecdotal example, but there might be some relevance to your situation.

    maybe one the smart kids can explain the reasons behind this.

    I know there are very satisfied p/j players out there. i have had 2 basses with p/j setups and so far have been happier with the p sound on basses without a j. ymmv.
  15. uOpt


    Jul 21, 2008
    Boston, MA, USA
    Do you want variety or do you just want to fix your sound?

    Two-pickup setups are problematic since you cannot mix two passive pickups without changing all kinds of other sound relevant parameters. If you want more "bit", always, exchange for a P pickup with more bite.
  16. Matthijs


    Jul 3, 2006
    If you wire the blend as i described the effect on your pure p sound will be close to nothing. A switch will reduce that to completely nothing.

    You can probably find a standard schematic for a blend somewhere on tb. Al you have to change is leave out the connections from the blend pot to ground.
  17. dvlmusic


    Jul 24, 2010
    Alameda, CA
    I added a J pickup to my MIJ P about a year ago and had the shop wire me a stacked V/V in for the first pot and I left the tone the same. I love the classic look of the 2 knobs on a P and I wanted as little alteration to the bass as possible.

    If you're interested in a kill switch you could always put a Push/Pull in for the tone knob and have it bypass the J pickup when pulled up. I'm not sure how you'd wire this but there has to be a way. I put a Push/Pull kill switch in my Jazz under the first volume knob as an experiment and it works great as a mute button. There's gotta be a way to defeat the J pickup in a similar fashion.

    Do you want the J in the 60's or 70's position?
  18. dvlmusic


    Jul 24, 2010
    Alameda, CA

    Here's my bass. The stack knobs are Fender branded and the shop supplied the pot.
  19. pbassnut

    pbassnut Supporting Member

    Sep 27, 2004
    Falls Church, VA
    pbassnut - Are you saying that the soloed P-pup would not sound as good as it does now? Is there a way to wire the P7J-setup so that this won't happen?

    Yeah, that's exactly what I'm saying ... the addition of the Jazz pickup to the circuit degraded the Precision sound (it wasn't quite as "live" sounding as the Precision pickup with no other pickup in the circuit) ... even if the volume control for the Jazz pickup was turned all the way down. I believe this was due to the loading effect of the second pickup. The difference wasn't night and day, but it was noticeable. As far as how to overcome it, I defer to the more knowledgeable among us. I wonder if using a 3 way pickup selector with a master volume and tone instead of the standard VVT setup might eliminate the loading effects?

    Maybe the Jamerson set, but I'm using the FS set (43-104) and they're not "all thud".

    I used to use the 45 - 105 set and kept them on my basses for a long time so they did get pretty "thuddy" for me which I liked. However, as arthritis has gradually kicked in over the years, I've moved onto lower tension flats like the Fenders I mentioned and Lakland Joe Osborns.
  20. Doug Parent

    Doug Parent Supporting Member

    May 31, 2004
    San Diego, Ca.
    Dealer Nordstrand Pickups.
    Skip the temptation to follow through with this idea. Bad idea. Sorry I am so direct sometimes.

    Heres the reasoning.

    The phase cancellation is bad.

    A J pickup in the 60's location in combination with the placement of the P-Bass pickup is HORRIBLE. The nasal tone mess as a result is, in my opinion, worthless.

    I have a Warmoth PJ5 that I built as an experiment. 60's spacing on the bridge. It's a total waste of money.

    J pickups work with J pickups that are 3.5 to 4 inches apart.

    A PJ combination puts the bridge pickup 2.25 inches from the treble coil of the P. Honk and nasal city.

    Sounds like you are going through with this anyway but I wanted to have my two cents thrown in for another TB'er. Good luck!

    edit: otherwise will flame my opinion or cite the fact that many manufacturers build PJ basses. My response: GOOD. They are feeding the economy.

    I was just at the Carvin factory in San Diego today. Tried the PJ5 and the plain P5.

    The plain old P5 (passive) kicks the PJ's ass. I'd NEVER get another PJ.

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