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swap pre-amp, pickups or both...

Discussion in 'Pickups & Electronics [BG]' started by dbthump, Apr 16, 2009.


  1. dbthump

    dbthump

    Mar 20, 2009
    Tampa
    Thanks for looking. I know it's wordy, and I cut it down as best I could. I know that "sound" is subjective to taste but I'm thinking anything's going to sound better than my OEM. My pup cavities are about 1" x 5.5". It seems my only choice for a swap is the Bartolini G6 narrow soapbar.

    The pickup just "picks up" the sound and doesn't necessarily "filter" it, it's the pre-amp that does that, i.e. allows you to project the sound you want to the amp?

    If I switched just the pups I'd get a new different sound (A), just the pre-amp another (B), and then both pups and pre-amp a third (C). Is that accurate?

    Which component more affects the sound; the pickups, pre-amp, or both? I'm sure the answer is all three. So let's say I'm on a budget and I can only get one or the other. Wouldn't the pre-amp be more affective in exploring a new sound for my bass?

    I have a late 90's active Fernandes Gravity 6 that has their "brand" pups and some strange pots. Stewmac doesn't carry pots that match my setup so they suggested that I either find a company that does or swap them out, i.e. change the sound.

    The stamps on the pots read: volume = B-10K ohm AP, treble = B-100K ohm AP, bass = B-100K ohm AP, pup blend = either * 50K ohm x 2 P or 250K ohm x 2 P. The genius that soldered the ground on the blend pot covered some of the text, so I'm not exactly sure if it's 50K or 250K. Any thoughts on which it is and what do these values mean anyway?

    I've got pics here if you want to look at them.
    http://i2.photobucket.com/albums/y48/dbthump/Gravity6electronicslayout.jpg
     
  2. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Not true! Different pickups sound quite different from each other. So in essence they do filter the tone in one way or another. It's usually by adding a resonant peak near their upper frequency cutoff, and by having different responses to highs and lows.

    You can get very flat response and transparent pickups, but they aren't common. So generally you want something that will be a faithful reproduction while offering a good balance of highs and lows, etc.

    Even when choosing a Bart pickup, some are deep and a bit on the dark side, and some are bright and open, even though all are clear sounding. So they sound like your bass, but there is some filtering going on.

    Preamps are more alike than pickups, since a high quality preamp should pass the tone of the pickup unaltered when the tone controls are flat. Most do shift things a bit when set flat because of the tolerance of the pots and other parts, but they are close.

    So then the difference between preamps comes down to the quality of the active components, and the center frequencies of the EQ.

    So if you like the tone of the current pickups, and not the preamp, then get a new preamp. But usually better pickups will make a big difference.
     
  3. dbthump

    dbthump

    Mar 20, 2009
    Tampa
    Thanks SGD. So if I feel like tinkering I could get the G6's and wire them to my current pre-amp and see if that does anything for me.

    Any thoughts on what the numbers mean on my pots, or does that matter?

    I've called the phone number listed on Bartolini's website and spoken with Tom a couple times. His honest opinion is "if you like the sound then why change it". While I find that refreshing from a "salesman" I don't necessarily agree 100%. If we all liked the original sound there wouldn't be so many after market solutions. I gotta believe the Bart's pups would better represent the sound of my bass as compared to the current no name pups.
     
  4. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    I think people change pickups when they don't like the sound of the originals or want something different.

    Having said that, I had a bass in my shop one day to have new pickups and a preamp installed. It was a brand new ESP LTD with their soapbars and preamp. I thought it sounded fine.

    Then I installed a pair of Barts and an Aguilar preamp and, and wow, what a difference.

    Night and day.
     
  5. Mike Shevlin

    Mike Shevlin

    Feb 16, 2005
    Las Vegas
    Bartolini Pickups & Preamps are just spectacular - they are always my first choice.
     
  6. dbthump

    dbthump

    Mar 20, 2009
    Tampa
    I think I'm getting both today. Now just trying to decide between 4.5, 4.6, 4.7 or 5.4. I Think I'll be getting a non-A/P set which ever I choose, which will mean active only, correct? No sense in having all those knobs and going passive right? Seems silly to me but I don't know.
     
  7. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    I installed an active/passive switch in one of my basses that has a pre. I never use it.

    I did it for testing purposes, but for normal playing I see no point. As far as having it in case your battery goes dead. I've never had a battery go dead, and my first bass with a preamp (Bart TC-1) was back in 1977!

    I've broken strings during gigs, but never had a battery go dead.
     
  8. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Are those pickups active? Or the bass has a preeamp? B-10K is a 10K linear taper. All these pots are easy to find, but you can't get them at Stew-Mac.

    If you are replacing the preamp you will use new pots that come with the new preamp.

    You can take a reading on the bend pot with a meter. If the pickups are passive and connect right to the blend, then it's probably 250K. Even an active setup wouldn't use a 25K blend.

    Is there a reason you want to change the electronics?
     
  9. dbthump

    dbthump

    Mar 20, 2009
    Tampa
    That's what I figured too.

    I don't think the pups are active, and they do connect directly to the blend pot. The battery seems to be attached to the circuit board.

    Because I can. :p No but seriously, I kid. I like to tinker; build my own computers, add aftermarket bolt-ons to my car like springs/sway bars, CAI, tear out my car stereo once a year and rebuild it... So in some respects it is because I can and have the knowledge and confidence to do it correctly. By no means am I am I luthier, but that's why I ask for advice from experts like yourself. Much appreciated.

    For one, the bridge pup "clicks" sometimes when I pluck a string and my fingers hit it as I move to my next note. Mind you I'm not a rocker. My action is low, volume is high, and I'm practicing so that I have no tension in the muscles to have a more relaxed "stroke". Merely tapping the pup produces an electrical pop. Aside from that I feel the electronics are likely "low grade". I can't confirm it, but I can assure you it's no were near the quality of what you swapped on that ESP.

    I just spent about 1 1/2 hrs on the phone with the owner of bestbassgear; very nice guy and regrettably I didn't catch his name. I told him about my conversations with Tom at Bartolini, and we agreed on the G6 CB with a non A/P 4.7 pre. I can't wait. Worst case scenario; I hate the sound, revert to stock, sell the setup on ebay and take the loss as a lesson learned. I've played with Barts before so I don't think that'll be the case.
     
  10. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Oh I know too well... I take everything apart and have done that since I was a kid. I used to mod my basses so extensively that I decided it was time to just design my own. Same with pickups.

    Probably lack of shielding in the pickup... that's not good.


    I'm sure they are.

    Oh you wont hate them, that's for sure. I started using Barts back in 1976 when they were called Hi-A, and I've been a big fan of them since. I used them as a tone model when I was designing my pickups. I wanted the Bart warmth mixed with active type clarity.
     
  11. SteveC

    SteveC Moderator Staff Member

    Nov 12, 2004
    North Dakota
    I swapped my humming single coil jazz pups for non-humming Bartolini's. While I was at it, I put a Bartolini preamp in as well. I love the Bartolini sound. I recently put some Bartolinis in a passive jazz bass and it was a noticeable difference - even without the preamp.
     
  12. dbthump

    dbthump

    Mar 20, 2009
    Tampa
    I'm so stoked! He's already shipped it and I'm all giddy just waiting for it. Got shielding too so I can't wait to see what difference that makes.

    I also might get my "new" Gotoh bridge late next week as well. I don't know if you saw my other post in repair, but basically Gotoh dug up the parts to reproduce the original bridge for this bass for less $$ than what their current line offers. I've not seen saddles like these before. The center raises up and locks to the preferred height, but someone stripped most of the lock nuts.

    BridgeCrop2.
     
  13. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    I remember those Gotoh bridges. They are from the early 90's. I wanted to use those on my basses but couldn't find them in the States, so I used a different Gotoh bridge. Now I use Hipshot stuff. ;)
     
  14. dbthump

    dbthump

    Mar 20, 2009
    Tampa
    After I get my new one I'm going to tap new threads into the old one and replace the stripped lock nuts. We'll see how that goes, but I may not have time for that once I get the bass re-rigged.:D

    I think I'm going to spontaneously explode just sitting here waiting to get off, go home to jam!
     

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