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Noise in the path; Is it my bass or the FX unit?

Discussion in 'Effects [BG]' started by stettoman, Sep 25, 2003.


  1. This may be a difficult question to answer since none of you can actually be here to hear what's going on, but I'm trying to figure out what's up with my signal path---I'm pretty sure it's my bass, but there are strange circumstances, so please bear with me...

    I'm getting extremely loud noise from my DigiTech StudioQuad with my Spector NS-2. Now, to answer the obligatory questions, yes, the electronics are grounded to the bridge. Yes, the batteries in the bass are brand new. No, the same thing does NOT occur with other instruments (passive) plugged in. No, the bass does not generate any noise through the amp or any other rack units. The Quad's output level is set at -10db...

    Through the Quad, however, the signal "snap, crackles, and pops", hisses loudly, and there is an intermittant 60 cycle hum. This occurs most prevalently when using the bridge P/U (Bartolini J), but all the pots crackle when touched or turned (not a "dirty pot" sound, but more of a very harsh "buzz").

    The noise is subdued slightly when the strings are touched, and disappears almost completely when the input plug/jack on the guitar is gripped firmly. The lithium batt. in the Quad was replaced yesterday (yes, this was happening BEFORE the battery replacement).

    The Spector is a late '80s Kramer, I replaced the bridge P/U myself and recently had it in to a guitar tech to make sure that it was wired correctly (it was out of phase with the other P/U)...He did not do a diagnostic on the active eq, but now that's exactly what I'm concerned about--except that this doesn't occur with any other gear.

    So, any thoughts? I'd really like to use the Quad, but the noise it generates with my bass makes it irritating at best. Has anyone here had any similar experiences and how was it remedied, besides eliminating the offending unit?

    Sorry for the windy post...
     
  2. jgsbass

    jgsbass

    May 28, 2003
    Floral Park, NY
    It sounds like a grounding issue. Especially from the fact that it almost disappears when you touch the jack. Does the bass make this sound without the effects connected? Is the effect unit using a wallwort powewr supply and did you trying to reverse the polarity of its power supply?
     
  3. Yeah, I tried reversing the polarity on the Quad-No difference. When I hit the bypass button it goes quiet as a sleeping baby, no noise at all, including the buzzing pots...
     
  4. pbd

    pbd Commercial User

    Jul 17, 2003
    Metro Detroit
    owner Procables N Sound
    it sounds like a bad cable. loose wires flopping against each other. if it's not the cable and if your unit isn't under warranty open the hood, DON'T TOUCH anything with your bare hands. check to see if the solder connections to the pots are solid through the circuit board. do this with the power off, you should be able to see if the solder is broken when you lightly wiggle it. use something non conductive to check it and be aware there are components on the circuit board that can be dangerous to your health.
     
  5. Well, I pulled the lid. Everything appears sound. Like I said, the other instruments I've plugged into the unit (an electric and an acoustic guitar) are hush-quiet, leading me to the conclusion that there's a problem in the bass's active electronics. I'm going to pull the batteries on the bass (assuming that the Spector is set up to go passive w/out power) and see if that changes things any. There's a processing chip on the board, and I wonder if it hasn't "gone south" after all these years of hard use. The chip is removeable, in a plug-in style receptacle, so I think it was made that way for a reason...:confused:

    I also have a call in to my elec. tech, maybe he can put it up on the scope and find potential causes for my problem.

    I appreciate the responses guys. If anyone comes up with any more input, please enlighten me--I'm just a player, not a mechanic!!!:D
     
  6. pbd

    pbd Commercial User

    Jul 17, 2003
    Metro Detroit
    owner Procables N Sound
    It sounds like your on the right path to recovery getting a tech on it. Hope it works out well.
     
  7. It was NOT the FX unit...It was NOT the bass...It was a 9v battery!!

    Though I never thought to change out the batteries, I did remove them from the bass (this eq unit uses 2 9v) and test them for voltage--they both looked fine.

    My tech smiled at me as he held out a bill and the offending battery. Apparently one of the cells in the 9v found a way to short out and caused some kind of imbalance in the circuit, resulting in all kinds of wierd stuff.

    I put in a pair of brandy-new Duracells and the setup is as quiet as a glass of water.

    Could someone check on me ocaisionally to see that I'm changing batteries regular???:rolleyes:
     
  8. pbd

    pbd Commercial User

    Jul 17, 2003
    Metro Detroit
    owner Procables N Sound
    The bad part- all the lost time. The good part-you now know your equipment inside and out! Check out duracell pro line, 'Procell'. They're great and last a long time.

     
  9. pbd

    pbd Commercial User

    Jul 17, 2003
    Metro Detroit
    owner Procables N Sound
  10. ...And some nice prices too!