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Help Me rewire/install pickups electronics into my bass!

Discussion in 'Pickups & Electronics [BG]' started by Luke19Boarder, Oct 6, 2009.

  1. Alright, so here's the deal ... I'm looking to upgrade the electronics and pickup in my bass.

    What I have currently:

    OLP MM3 (passive musicman 5-string copy)

    One of the volume knobs broke off and doesn't work (half the pickup is always turned off), the remaining two knobs (volume and tone) are pretty poor. They kinda crackle and don't roll off smoothly.

    SO, what I am looking to do is replace the pickup and likely all of the pots and rewire it.

    I have ordered a nordstrom mm5.2 replacement pickup (the OLP model that will fit this bass exactly). As I understand, it's essentially 2 j pickups in one casing.

    I have replaced pickups before, but never the pots/knobs.

    I am also considering wiring the pickup with a series/parallel push/pull switch, as i have heard that isn't too difficult.


    What type of pots do i need? I have been recommended to get them from stewmac, and see that they have different specs (25k, 250k, 500k, etc.) and I really have no idea what that means. Which do I need?

    I play in a band in which the bass isn't typically in the forefront, but many are bass-driven and I need to cut through. I occasionally use effects such as phaser and overdrive. I use both a pick and fingers (used to play with pick more, now I use fingers more, but still utilize both). I am going for an aggressive tone without being too harsh. Is a series/parallel switch a good idea for me, or should I just wire it one way or the other? I'm not 100% sure on the tonal differences between the two.

    Are there better sites for getting electronics than stewmac that you can recommend?

    A wiring diagram would be supremely helpful in letting me know exactly what I need to order as far as electronics as well as how to wire it.

    Any other suggestions are greatly appreciated.

    Sorry it's so long, and I have read a lot of posts/threads in search for an answer, so please don't tell me to do a search.

  2. And to all of you who tend to tell people not to upgrade junk basses and save up for a real MM ... I don't want to hear that. I got this bass for free, repainted it myself, and am looking forward to making it at least a decent-sounding bass for under a couple hundred bucks.

    here's a couple pics of it, in case you want to see what I'm dealing with:

    here you can see the missing volume knob and the pickup placement:

    this is a newer one after i put block inlay stickers on it, just cuz i think it looks sexier :)
  3. Cyber Soda

    Cyber Soda

    Sep 24, 2008
    I need to do some upgrades to mine so bump & subscribed.
  4. Personally, I prefer 500K pots, but it's personal preference.

    These threads may be helpful:

    FWIW, I've recently changed my stance on linear versus log. I would strongly suggest a linear taper volume pot with a log taper tone.

    I don't see any downside to adding a series/parallel switch.
    You can use a push/pull pot, so as to avoid any permanent modifications to the bass, and if you don't like the series tone, you can just forget the switch is there.

    I can draw you a wiring diagram if necessary, but you need to explain the setup you have/want.

    Stew Mac isn't exactly the best place to buy your electronics.
    I would buy from GuitarPartsResource or BestBassGear personally.
    Allparts and eBay are options too.
  5. thanks a lot, that's very helpful.

    on the difference between 250k and 500k pots, i'm under the impression that the 500k pots will have a bit of a brighter tone ... will there be a noticeable difference on the low end at all?
  6. No, not really.
  7. Alright, cool. I'll probably go with the 500k, just to be on the safe side. I can always roll off the tone knob a bit if it's too bright, or turn my tweeter off in my cabinet.
  8. Oceanstrat


    May 13, 2009
    Great timing! I am doing this with my OLP Musicman 4-string. Be aware, I bought the 500 pots and they are physically bigger than the ones OLP used (seems like they used mini-pots.) This required some very careful routing with a dremel tool in order to get the new pots to fit into the body.

    I do have a question about the resistor......is there a better one to go with? Also, what does changing the resistor out do to overall sound/tone? I have seen recommenedations to go with "oil filled" resistors but....have NO idea what effect it would have. Guitar shop owner said to use the same resistor.... hmmmm.

    Thoguths? Thanks!:bassist:
  9. I'm glad you posted! I'm trying to avoid having to do any routing ....

    will the 250k pots be smaller than 500k?
  10. No, he is talking about the physical size of the potentiometer, not it's resistance.
    Your bass was designed to use mini-pots, not full sized pots.

    For reference, this is a full sized pot:


    And this is a mini-pot:
  11. I believe you are referring to the tone control's capacitor, not a resistor, correct?

    Don't buy into that hype.
    An expensive capacitor is not going the sound any better than a decent one.
    The reason why people usually think that expensive capacitors sound better is that the cheap ceramic capacitors used in a lot of basses are usually manufactured with very poor electrical tolerances.
    Once you get a decent quality capacitor in your bass, that is about as good as it will sound.

    Personally, I recommend Orange Drop capacitors. They cost me $1.49
  12. Thanks. I'm new to most of this jargon, and I want to make sure I get it right before I tear apart my #1 bass.

    ...I might just end up taking it to the shop and having it professionally done ... depends how big my next paycheck is, haha.

    Anyways, are mini-pots any different functionally than regular sized? In other words, would it be worth it to get the regular sized ones and route out extra space in my control cavity? I don't want to have to do that, but if it will make a considerable difference...
  13. Oceanstrat


    May 13, 2009
    Thanks Line6man, that confirms what I suspected wrt the capacitor....of course, I was calling it the wrong name!!! Good questions about the pot size...again, I read to put the larger ones in...hmmmm, maybe that doesn't matter either?
  14. They are functionally exactly the same so there's absolutely no point in routing your bass to take them. If you've already bought the larger ones then binning them and getting new mini pots will still cost considerably less than getting the woodwork done :).
  15. Nope, I haven't ordered them!

    And that's pretty much what I figured, but I thought I'd double check.
  16. Oceanstrat


    May 13, 2009
    I just finished mine. It only took a couple hours at home. The previous owner completely jack the wiring to keep it going as the pots broke so: I cut all of the wires, cleaned and stripped the ends, installed 3 new large 500k pots, used a dremel with sander attachment to route out the hole a bit, then soldered all of the wiring back in usuing the J bass diagram supplied by Line6man (the OLP pickup is wired like two J-pups sitting next to one another.) Installed a Hipshot and new ouns and....presto! Bass works great!!! The "routing " was not a big deal...I traced the outline of the electronics cover onto the body with a china marker so it kept me honest ;) Go for it....you'll have fun and learn something about your bass! Just remember, "measure twice, cut once!"
  17. Hey Guys,

    Good thread about the wiring, pot differences, etc. Thanks!

    Luke, did you put the Nordy in? How does it sound compared to the stock OLP pickup? how would you describe the sound? Punchy? Warm? Growly? All of the above?

    I'm thinking about doing the same thing to my OLP MM5.
    Also, did you find any other pickups that are size-identical to the stock MM5?
    I haven't run across any good replacement pickups which are exactly the same size as the stock OLP MM5.

  18. I got my pickup installed a couple months ago ... I opted against replacing any of the other electronics in the bass though.

    I am thoroughly impressed by the tone of the Nordy compared to the stock pickup. It is much more punchy and growly ... with the most improvement on the low B. It is much more defined and way less muddy. With the tone knob turned all the way down, you can get a pretty warm tone as well.

    I wouldn't be able to recommend another pickup as a direct replacement ... the nordy is the only one I found when I was looking.