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replacing pickups for carvin LB70

Discussion in 'Pickups & Electronics [BG]' started by frankosaurus, May 20, 2002.


  1. frankosaurus

    frankosaurus

    Feb 27, 2002
    San Jose
    hey... I got some nice Seymour Duncan jazz bass pickups that I'd like to install on my 1999 Carvin LB70 bass. The pickup dimensions seem to match exactly... The catch is that the existing Carvin pickups each have 3 wires as opposed to the 2 on the SD's, and they're running through a preamp. Each existing pickup is soldered onto the preamp circuit board through terminals marked S, R, and BP (one for each wire). Any idea what these letters mean?

    So, my question is, is it possible to install the Seymour Duncan pickups on my Carvin bass and keep the preamp? Any suggestions on where to solder the wires? Thanks!

    --Frank
     
  2. chucko58

    chucko58

    Jan 17, 2002
    Silicon Valley, CA, USA
    I paid for all my gear myself. Well, me and MasterCard.
    S = Shield

    R = Red (hot)

    B = Black (cold)

    On the newer Carvin preamps (one chip version), the B and S are wired together internally. Older Carvins have a differential input preamp that isolates S from B.

    Best bet is to hook your new Duncans up to B and R. Make sure you get the colors the same on both pickups: same color to B and same color to R. If they have shielded cable, hook the shield to B and the center conductor to R.

    Does that help?

    (edit: fixed minor spaz in terminal names)
     
  3. frankosaurus

    frankosaurus

    Feb 27, 2002
    San Jose
    Chuck--

    Thanks for the reply. For the purposes of installing the new pickups, does it make a difference if I have a differential preamp or not? On my preamp, the S and B are separate terminals and have separate wires running to them-- for each pickup, there's basically a thick black wire running to the S, and thinner red and black wires running to the R and B terminals.

    I don't think I have shielded cable on the Duncans. Basically, it's just braided fabric around the wires, one black and one yellowish-white.

    Based on your suggestion, I plan to hook the black wire to the B terminal, and the white one to the R terminal--- and I'll leave nothing hooked up to to the S terminal. Does that sound right? Thanks a lot for your help!!

    --Frank
     
  4. chucko58

    chucko58

    Jan 17, 2002
    Silicon Valley, CA, USA
    I paid for all my gear myself. Well, me and MasterCard.
    That should work. If you get a lot of hum and buzz, try swapping the wires. I'm kind of surprised Duncan doesn't shield the cable.
     
  5. geshel

    geshel

    Oct 2, 2001
    Seattle
    Shouldn't the braided wrapping get connected to S?

    [edit] oops just saw that was "fabric". Normally that would be conductive shield wrapping however.
     
  6. frankosaurus

    frankosaurus

    Feb 27, 2002
    San Jose
    yeah, I think he was going for a retro effect since they look pretty dingy.
     
  7. frankosaurus

    frankosaurus

    Feb 27, 2002
    San Jose
    thanks for the installation advice. I finally replaced the carvin stock pickups. the new ones (antiquity 2) are great. They required a small amount of routing around the screws on the neck pickup. I tried them at a gig last night and they were a big improvement.

    There is a hum if I solo either pickup, which is to be expected with single coil... No problem there, though. They really cut through the mix and I'm looking forward to recording with them.

    --Frank