No bass coming from bass amp

Discussion in 'Hardware, Setup & Repair [BG]' started by Bolt8244, Jan 2, 2021.

  1. Bolt8244


    Jan 2, 2021
    Okay, so this is strange. I've seen similar threads, but I'll include everything I've already checked. I don't know what else to check. So at first it was a popping and buzzing sound whenever I touched metal, knobs and bridge. Now, I have no sound at all coming through the bass amp.

    Bass and amp were purchased at the same time a year and a half ago. Fender Pbass deluxe with active/passive toggle and an Ampeg ministack cabinet/head combo. If that helps.

    I have taken the bass into Guitar Center, not thinking it could be the amp at first, to look at the wiring. The tech said it was all good, so he plugged it in and it works on their amps fine.

    So now I'm thinking it was the amp, or the cord I was plugging it into, or something else. So I went home. I plugged it into the same cord and nothing, tried another cord, still nothing. So I plugged my Les Paul guitar into my bass amp, same cord, same settings on the amp and it plays fine.

    So my bass plays fine on other amps, and my guitar plays through my bass amp with same cords I was using with my bass fine. But my bass won't play anything through my bass amp. I don't know what else to try.

    Does anyone know why a bass amp would play a guitar fine but not a bass? I'm really confused. Any help would be appreciated here.
  2. RSBBass


    Jun 11, 2011
    I suspect the jack is dicey. Although they shouldn't, the plugs on cords can vary a bit in size. Being active you may be shorting something in the switching in the jack or not making good enough contact to turn the bass on. I would open the control cavity and take a look for a loose wire, corrosion,or or poor contact.
    96tbird and LoveThatBass like this.
  3. @RSBass could have it. Does the bass work at all in passive mode? Is it a barrel jack or an open style? Upload a picture of the jack and also where the wires are connected in the cavity.
    RSBBass likes this.
  4. el murdoque

    el murdoque

    Mar 10, 2013
    When the amp works with a guitar and that same cord does not work in the bass, while the bass works on other amps, it should be the connection. Which is weird when swapping to a different cord does not work. When the bass is plugged in, do you hear absolutely nothing?
  5. Samatza


    Apr 15, 2019
    Probably a faulty jack on the bass and a questionable cable.

    Ive had instances where a bass would not play but another would with the same cable and amp.

    If it’s the long barrel type jack they do suffer from wear and tear more than the regular type.
  6. bpc


    Mar 29, 2016
    Central Scotland
    Is is possible the the GC guys tested the bass in passive mode and you are testing it in active mode? The earlier symptoms you described could be the battery running low, maybe it is dead now. Try passive mode and maybe change the battery.
    RSBBass likes this.
  7. Another possibly obvious question, the cable that doesn’t work with your bass isn’t a TRS or stereo cable is it? That type of cable won’t complete the circuit for the battery and active electronics won’t work.
    RSBBass likes this.
  8. Bolt8244


    Jan 2, 2021
    I pulled the output jack out of my bass and the cable seems to make good connection in the bass. At GC he tested both active and passive modes, and they both worked there. In my bass amp neither active nor passive work. I'm assuming it is the amp still, but have never taken apart a bass amp.

    My Ampeg amp has a 0db port and a -15db port, their one works on my bass.

    Attached Files:

  9. Bolt8244


    Jan 2, 2021
    Oh, and the main cable I'm using is a guitar cable I've used since high school on multiple instruments without a problem. I'm 35 now, so it's not new, but like I've said before, I've tried several other cabels workout any difference. There is no sound no matter what cable I use.

    Attached Files:

  10. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    In the pic, the cable is not fully plugged in. That would cause your problem.
    RSBBass likes this.
  11. Bolt8244


    Jan 2, 2021
    Great, if that's the case, what does it look like when fully inserted? There was good metal contact, so I assumed that was what I was looking for. It's that not correct?
  12. JTE

    JTE Gold Supporting Member

    Mar 12, 2008
    Central Illinois, USA
    The output jack on an active bass has two places the tip of the plug can contact. A passive instrument has one, the tip. Active uses a tip, ring, and sleeve jack. The plug can connect to the ring connection which is there to complete the circuit so the battery starts powering the pre. So you have to be sure the plug goes all the way in so the tip of the plug makes solid contact with the tip connector of the jack. If the tip only connects to the ring connector there's no signal going to the cable.
  13. can you post a close up picture of the 1/4" cable end connectors?
  14. The tip of the plug should only contact the longest prong of the jack. Like previous poster says, your photo shows the plug is not pushed in far enough. The plugs sleeve contacts both ground and the ring (shorter of the two prongs) on the Jack. This acts like a switch by connecting ground and ring completing your electrical connection of the battery to the negative connection of the circuit board. You do not want to leave your instrument cable plugged in to the bass when not using it as it will run the battery down.
  15. Element Zero

    Element Zero Supporting Member

    Dec 14, 2016
    Try a different cable. By the picture, it’s not plugged all the way into the jack.
  16. Bolt8244


    Jan 2, 2021
    I've tried 3 different cables and they all do the same thing. I've used this cable for a year and a half without a problem what would cause it to not go all the way in now? I see what you are saying, it doesn't seem to be going in. I just don't know what it would do that.

    MYLOWFREQ Supporting Member

    May 13, 2011
    You just need to push the jack all the way in. If it's too tight, bend the tip terminal on the output jack backward slightly so there's less tension.
  18. Bolt8244


    Jan 2, 2021
    I didn't have it all the way in for the picture, that isnt the issue. When I take it apart and plug it in, there are no issues. It's only when it's put back together that there is a problem. When the nut that attatches to the output jack is tight it causes it to buzz, lots of static, sometimes no sound at all. When I lossen that nut I can play it with good sound. However, with it loose, when I tip/move the bass it can hit the wrong spot and cause it to do the same thing. So my tuner has a mute, so I've been muting it when I move my bass to a guitar stand, because now it's only in that transition that it makes all the noise. I have a temporary work around, but I would like to get it fixed. Has this happened to anyone?
  19. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician
    That sounds like the tip connection of the jack is getting shorted to ground. When the nut is loose that contact is just clear of the ground (shielding paint or foil, a bare ground wire or the body of a pot for example). When the nut is tightened the tip connection touches the ground. I ran into this problem on a number of Lakland basses when the jack rotated a bit and the tip came into contact with the case of one of the pots. The solution was to rotate the jack so the tip was away from the pot and tighten it there. I also fused a bit of shrink tubing over the body of the jack so that it covered (but was not shrunk to) the tip contact - just a bit of an insulator in case the jack rotated again (it already had a lock washer to help prevent rotation).
    Lownote38 and LoveThatBass like this.
  20. Bolt8244


    Jan 2, 2021
    Thank you, I'll check that out.
    LoveThatBass likes this.
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