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phase cancellation

Discussion in 'Pickups & Electronics [BG]' started by nil, Jul 21, 2005.


  1. Hi all,

    My newly aquired Rickenbacker 4001 seems to really lose output when both pickups are cranked (sounds like phase cancellation).

    Rolling off volume slightly from one pickup restores the girth, but it's finicky and one bump and my volume/tone is all gone again (probably a new lower value pot would help).

    To reverse the phase, do I simply swap the hot and earth wires from one of the pickups around? I notice that the neck pickup has two earth wires - are they common, or...? (i'm not too knowledgable on how pickups are wired)

    thanks!
     
  2. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    Yep, just reverse the leads on one of the pups.

    Never saw a pup with two grounds within the jacket. It's possible one may have been split. It's also possible the second was used to function along the lines of grounding plate. The Ric bridge I've got is like that but the "grounding plate" ground was a seperate wire coming from within the pup with a ring soldered to it - only a hot lead and ground within the jacket itself. The neck only has the hot lead and ground. These are 70's Rics.
     
  3. Sweet, i'll give it a go. The neck pickup is a toaster with the "split" earth - there's a feed to it's mounting plate and a feed (along with hot) to the selector switch.

    Worst comes to the worst i'll work out the correct value for one of the volume pots when it's adjusted correctly and hard-wire the volume of the pickups! :D
     
  4. This may seem really stupid, and I'm not too great on electronics, but make sure that you're not plugging in your standard cord into the stereo jack of the Rick. (Do the new ones still have a stereo out?) Although, I suppose if that was the case, one or the other of the pickups probably wouldn't be working at all...
     
  5. Most Rics (old and new) have the stereo, there are exceptions though. And yup, it was thru the normal output! ;)

    Just weird 'cause the two other Rics I own ('89 and '98...the one with the problem is a '79) don't exhibit the same problem with both pickups dialled.
     
  6. I'd say take it to a specialist if you can afford to. I've taken a lot of time and messed too much up trying out different "solutions" when I could have just taken it into my tech shop and have it done right the first time and out the door the same day, sometimes, depending on the problem. You're right; it's "weird". Maybe you should open all three up and see what's different in the '79 that doesn't show in the other two. Seems that the electronics shouldn't vary too much. Again; just a thought. Good luck!
     
  7. LowEnd Theory

    LowEnd Theory

    May 31, 2005
    Yeah, i thought the same thing.....
    I decided to have my new QPs put in by a tech and they wired them out of phase. I have the same problem when i dial in both pups to the max.
    I gotta say this is really annoying. :rollno:
    Theyre supposed to be professionals right?
    Anywho, Does anyone know if this affects the sound or strenght of the signal at all?
    And when theyre both "phased out" what exactly am i hearing?
    Its way too trebley to be just one pick up thats on.
    its like it changes the whols strenght of the sound.
    Any ideas?
    LET
     
  8. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    As stated previously, just swap the start and finish leads of either pup and they'll be in phase. It's the same thing you do on stereo speakers when they're out of phase and same affect. The signal will both be louder and more full - with no annoying wierdness.
     
  9. I agree, no one's perfect. It's a matter of finding a tech you trust to do the job whenever you bring it in. There's a couple in our area that are really worth the money and time, and I'd probably go no where else, but it's hard to find them without references you trust, The other thing is that they stand behind their work. Why didn't you go back and say "hey! it's not right!", and make them do it over?
    You paid for it; if it's not right, make them fix it!
     
  10. LowEnd Theory

    LowEnd Theory

    May 31, 2005
    You're absolutetly right....
    which is what I'm doing today... :rolleyes:
    thanks guys.... Ill tell 'em a thing or too...
    or just to fix it.... :smug:
    LET
     
  11. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    actually that was the response to take for that bass. Phase may not be the issue and you really don't want to jack with somebody's work that wasn't done properly to begin with if you expect them to back it up. They have no obligation to back up their work if it's been tampered with by somebody after-the-fact. That holds true for anything you have work done on or have shipped to you.

    They should have checked the bass before it went out and YOU should never have walked out with it without checking it yourself. Nevertheless, the real test for a business is whether they back their product and how they treat you so now you have the opportunity to find that out.

    Another thought that comes to mind is that it is a bit odd you'd have two basses at the same time with phase issues.
     
  12. LowEnd Theory

    LowEnd Theory

    May 31, 2005
    Well,
    If any of you care or would like to know,
    I got my Jazz back today with the pups in order...
    They were actually good about it all and apologized for the whole thing. :p
    I just hate that i have to go through so much crap to get something done.... :scowl:
    I'll tell ya, the more you can handle yourself, the better :bassist:

    LET
     
  13. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    well sounds like you got the desired response in treatment.

    If it's done competently, the more a player can do the better is so in my experience cause a tech is not always readily available when the need arises, the bass doesn't need to be transported, and you don't have to be without the bass any longer than it takes you to resolve the issue. Bass electronics is nothing any player couldn't handle if he chose to. All that's needed is a few tools laying about the house, soldering iron, solder, and a meter which cost less than $30 total.

    The downside is that doing so will give you an appreciation and understanding for techs. Drop in mods rarely occur and it takes a good amount of grief till you get enough experience under your belt to where you can predict the inevitable and be prepared to adjust accordingly. It will often take more time to get even something simple right than if dropped off, left , and picked up from the tech - especially in the early going. It may also take longer to get a needed part than a tech would have it, as he may have the part on hand. If tinkering with electronics becomes a hobbie then spare parts are usually accumulated within 6 months or so and you'll likely have what's needed on hand - at least for a patch job.

    But a tech that is competent, backs his product, is respectful, charges reasonable fees, and gives an accurate time frame for turnaround is doing his job as well as can be expected under the circumstances.
     
  14. Did you ever address this inquiry? I'm curious, too...