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Overdriving the pu's on a passive bass???

Discussion in 'Pickups & Electronics [BG]' started by Squidfinger, Mar 11, 2005.

  1. Squidfinger

    Squidfinger I wish I could sing like Rick Danko.

    Jan 7, 2004
    Shreveport LA
    A few days ago I made the discovery that if I lower the volume on my completely passive Bob Glaub BEAD P-bass to 90% instead of full on %100 like I usually keep it it makes a world of difference. At %100 it's muddy and a tad distorted. At %90 it sounds just right :cool: . The pickups are actually pretty low (almost all the way down for the B and D) as I've balanced them myself so I know it's not because of too much pu height. I thought it was an eq problem for the longest.

    I talked to a much more knowledgeable friend of mine and he said I was overdriving the pu's and some passive instruments aren't supposed to be run at %100 volume.

    I wanted to put this little tidbit of info out there for anyone else experiencing similiar problems with their passive basses.

    Opinions? :ninja:
  2. You sure you weren't just overdriving the input of your amp?

    I don't know much about instrument electronics, but i would think how much volume they pick up is independant of the volume knob on the bass. I would think that the volume knob works more as an output power than as a preamp/gain control if that makes sense... Feel free to correct me.
  3. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    nicoli is correct. The volume knob reduces the volume after the pickups. You were probably overdriving the input of your amp or preamp.
  4. Squidfinger

    Squidfinger I wish I could sing like Rick Danko.

    Jan 7, 2004
    Shreveport LA

    OK, I tried what you guys said. I turned the volume back to %100 on my bass and lowered the input volume on my head (GK 1001RB-II) a couple of notches to 9 o'clock. No real change other than the obvious loss of volume, better but still muddy.

    I then turn the volume on my bass down again to %80-%90 and my tone goes from blurry to round, defined, and very smooth.

    What gives? :help:

    EDIT: some more info.

    input volume: 11 o'clock

    boost (post gain): 11 o'clock

    woofer volume: 12 o'clock

    bass: never past 12 o'clock
  5. Trevorus


    Oct 18, 2002
    Urbana, IL
    This could be due to an electronics problem. You might try a different value of potentiometer. If it is a 250K pot, then switch to a 500K. It would help brighten up the overall sound.
  6. Sonorous


    Oct 1, 2003
    Denton, TX
    Maybe you're actually turning the tone knob, and you just didn't know it?

  7. rumblethump

    rumblethump Supporting Member

    Mar 25, 2000
    Pioneer CA. 95666
    I have to agree with the original poster, my experience with passive basses has been the best tone comes with the volume pot backed off a tad. 90 % would be better than 100 percent. Just my ears. YMMV :bag:
  8. geoffzilla


    Oct 30, 2001
    Nashville, TN
    Endorsing Artist: Aguilar Amplification
    I recently discovered this with my Aerodyne Jazz. If I use just the P pickup at 100%, I get some mild distortion on the E string. I tried adjusting the height, as well as preamp levels with no improvement. When I backed off the volume on the bass, it really cleaned up the sound.
    I am considering replacing the pickups with Lindy Fralins, as I don't have this problem with my Fralin equipped PJ. Squidfinger, does your Bob Glaub have a Lindy Fralin pickup? I'd be disappointed to hear that you did.
    Also, I've noticed that this happens only with my sansamp or with the tube pre on my hartke. If I run through my solid state headphone amp, or through the solid state pre on my hartke, the problem goes away.
  9. ApeIsHigh81


    Aug 24, 2004
    My passive J sounds best at around 90% neck volume. Bridge I can turn all the way up, but the neck is about perfect at 90% like homeboy said :eyebrow:
  10. Squidfinger

    Squidfinger I wish I could sing like Rick Danko.

    Jan 7, 2004
    Shreveport LA
    Yeah, it sure does have a Fralin. Truth be told though I've gone back to pegging the volume at %100 because I think I've finally found the sweet spot on my GK rig. I'm primarily a pick player and before it was:

    input volume 11 o'clock
    Contour 12 o'clock
    treble 11 "
    high mids 10 "
    low mids 10 "
    bass 11 "
    boost 11 "

    This sounded great by itself but I quickly found out it sounded like ass in a band context.

    Input 10
    contour off
    treble 10
    high mids 12
    low mids 10
    bass 12
    boost 1

    This new setting has made the difference between my bass sounding like crap at %100 volume and being useable. That said it still sounds better at %90 but I need the volume. I would like to try a drop-in Raven Labs P-bass preamp but unfortunately it seems they just went out of business. :(
  11. BassJunkie730


    Feb 3, 2005
    First, changing your pot from 250K to 500k WILL not solve the overdrive problem because yo are effectively reducing the load on the pickup- so you'll get more highs but also you'll squeeze more gain out as well (that's an old guitar trick) Second turn down the boost on your GK - I've been using a GK 400 15" combo and a p-bass (can you say fog horn of DOOM) I find that if a keep the boost below twelve oclock and the input at 12 and just used the eq and master volume - I can get clarity. I'm suprised you said you got a clearer tone by upping the boost - strange. Anyway - hey if you are clear at 90% of the bass volume then use it for rhythm. turn it up whenever you take a solo and move up to higher frets - just a thought.

    BTW what cab are you using?

  12. Squidfinger

    Squidfinger I wish I could sing like Rick Danko.

    Jan 7, 2004
    Shreveport LA
    I'm using a GK NEO212. I really don't want to raise the input volume anymore because it becomes too noisy and harsh if I do.
  13. bass_drum


    Feb 13, 2005
    On my nobby meidel bass, if you put both pickups on 100% you loose a whole lot of volume and bass. If you put bridge pickup 100% and neck p/up 90%, works fine, and vice versa.
  14. alright, you cant overdrive pickups, it doesnt work that way, your overdriving your amp, your amp probably doesnt have that much headroom. how about you turn your amp down to the volume that it would be if your bass was at 90%. if its a combo amp, turn down the gain and up the master, if you have a pre amp power amp set up, turn down the pre amp and up the power amp
  15. klem


    Mar 14, 2004
    Hi! This effect may causes from the "passiv" electric. Two volumes and one "Tonblende".
    The "Tonblende" fade a lot of Frequencies away. You can use your Amp to "tune" this. More power. I like this sound, 100 bridge and 80% neck. A little bit through the "nose".

    My tip, change the pickups to an aktive version, may be EMG or something else.This is much more "smooth". Or use an "active electronik", Noll, Aguilar, Alembic or something else.

    I´m going to change the configuaration of one of my Nobby Meidel to "passive Bartolini" with an active Electronic. Noll TCM2 or a 2-way Aguilar. Klem