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Bartolini X6's in my Yamaha TRB6p totally screwed?

Discussion in 'Pickups & Electronics [BG]' started by Lorenzini, Mar 29, 2006.


  1. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    I put some Bartolini X6's in my Yamaha TRB6p and now, some very weird stuff.

    The knobs are Volume, pickup selector, bass, treble, mid (or at least I thought it was mids, it's the narrow, skinny one) and then the piezo flip switch.

    They all used to work as mentioned above. Now, if I rotate the mid knob to the left and select the neck pickup, I get 0 volume out of the bass. If I rotate it towards the bridge (opposite way) I get a VERY growly sound. I already tried unplugging the bridge pickup to make sure the neck pickup works, and it does, so that's not the problem.

    But at the same time, if I keep the mid knob at center and select the neck pickup, I get decreased volume and a VERY tame sound. Not the boomy neck sound most basses give off.

    Could changing the pickups have changed the effectiveness of the knobs? Should I just send it to a guitar tech?

    So I'm a bit confused. Can you help?
     
  2. C-5KO

    C-5KO

    Mar 9, 2005
    Toronto, Canada
    Bart X6s are great pups. It sounds like they're just wired wrong. Basically, your blend is messed up. You're blending for the bridge, and you get nothing, you blend for the neck, and you get a very hot signal. That's what I'm taking from your post. It sounds like it doesn't have anything to do with the mid knob.

    I'm no expert on wiring, but it sounds like they're been wired in some sort of strange series, or they're phased. Usually when pups are wired in series, the blend with take out all the signal when it's not centered. When they're phased, i believe it's a sort of hollow sound (I've never experienced phased pups before). If you can post a pic, or describe which colour wires you connected to where, it might be easier for the more electrically-technical savvy to help.
     
  3. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    What you have gotten from my post sounds spot-on.


    Yeah it's very hollow sounding. But I kind of LIKE the tone! I just know that they shouldn't sound the way they do... I sound like Steve Swallow now! However, I know it's not how it should sound.

    Thanks for the suggestion. I'll take a pic with my cell phone this afternoon and hopefully that will illustrate my problem.
     
  4. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    I'm no expert on the TRB*P's, but from what I remember about the couple I've played, there is no mid control--the "skinny knob" was a piezo blend control. So, by changing the position of that knob, you're adding or removing the piezos from the mix.

    Judging from your description, it sounds like you may have two issues: 1) the magnetic pickup blend not being wired correctly, so maybe you're getting both pickups in series as C-5KO suggested, and 2) the magnetic and piezo pickups being out of phase with each other, so when you have the "mid" (really the mag/piezo blend) in the middle you're getting the hollow "out of phase" tone.

    Mike
     
  5. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    yeah I always thought the skinny knob was something to do with piezo, but it was never obvious. For example, turning the skinny knob all the way up USED to make the bass much more punchy a la mid control and turning it down would cause it to lose bass/mids, so I guess I assumed wrong.

    Either way I think your assessments are right. If anyone else has any input, I'd appreciate it, but for now I'm going to consult my father who has a good handle on this stuff.

    Thanks,
    matt
     
  6. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    By the way, I just checked around online to find out if I could locate anything that documented the controls in more detail. The reviews I saw confirmed that the little knob is a mag/piezo blend. There are also several that said that the switch was actually a "bass cut" for the piezos.

    So, if the switch was set to be cutting the bass on the piezos, that would certainly explain why the sound was so much less punchy if you turned the skinny knob all the way in one direction (piezos only)...

    Mike
     
  7. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Thanks for the clarification. It's odd. I don't know that the mag/piezo knob is wired incorrectly as it worked prior to my installing the pickups.

    It could very well be that the pickups are out of phase and I will definitely have to consult my father
     
  8. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Sorry, I was just speculating why the function of the switch (bass cut on piezos) might make the mag/piezo blend control seem like it was actually a mid or low-mid cut/boost.

    I suspect the mag/piezo blend is fine, and the magnetics and piezos just got connected out of phase when you replaced the pickups. That might not be anything you did wrong in connecting the pickups--I'm not sure there's really a "standard" phase orientation between pickup makers, so the original Yamaha pickups may have a different phase orientation (not sure that's the correct term :confused: ) than the Barts. Regardless, you should be able to fix it by swapping the hot and ground wires on the Barts.

    Good luck!
    Mike
     
  9. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Sorry I'm a REAL newbie at this stuff.
    Swapping BOTH pickups, or swapping only 1 pickup's hot/ground wires?

    Mike, thanks very much, you should be a Moderator!
     
  10. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Glad I can help!

    Swapping the hot and ground on both pickups. The magnetic pickups seem to be in phase with each other--they're just both out of phase with the piezo (we think!).

    Mike
     
  11. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Mike,

    I swapped the hot and ground on the neck pickup-no change!
    Not for better or for worse.

    Any ideas?
     
  12. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Hmm, there was already something weird about the magnetic pickup blend, right? Maybe the control is not giving you output from the neck pickup? I'd try swapping the hot/ground on the bridge pickup, as well. That's just to fix the weird hollow tone when you blend in the piezos--I really don't have much idea what the problem with the neck/bridge magnetic blend might be...

    Mike
     
  13. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Mike,

    I just want you to know that I brought the bass to my dad's and he realized that there was a short in the wiring of the neck pickup. He resoldered it, put some shrinking plastic over it and it's playing like a dream - with thump!

    Thanks for all your help

    Matt
     
  14. C-5KO

    C-5KO

    Mar 9, 2005
    Toronto, Canada
    Glad you got that figured out. Good job Mike! It never ceases to amaze me the helpfulness at TB.
     
  15. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Awesome news, Matt!

    Mike
     
  16. SteveC

    SteveC Moderator Staff Member

    Nov 12, 2004
    North Dakota
    I find wiring preamps on a bass the most frustrating thing ever. It doesn't take much to mess up the entire works.
     
  17. Lorenzini

    Lorenzini

    Dec 31, 2004
    Los Angeles
    Yeah
    But it was MORE than worth the time and money put in.

    The bass is more versatile and the tone is TO DIE FOWA!
     

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