Amp cutting out, bad electricity?

Discussion in 'Amps and Cabs [BG]' started by Moo, Nov 13, 2005.

  1. Moo

    Moo Banned

    Dec 14, 2002
    Oakland, CA
    Hi, just played a 3 day gig in a convention center and had some weird stuff on the 2nd set of the 2nd day. My Eden 400 started to cut out somewhat like a bad shorting cord would make it do. A pop sound and then quiet, then it comes back, pop, quiet, repeat. I quickly swapped cords and then basses but it continued. When I got the amp home I couldn't reproduce the problem. For piece of mind I played the rest of the gig with another bands amp so I didn't try the Eden there again.

    If the voltage was dropping in my power source is this what would happen? And could I expect something like a Furman power conditioner to solve this? The power light on the amp never went out during all this so I think it was getting at least some power the whole time.

    I'm worried there may be an amp problem that may pop up on another gig.

  2. Sounds almost like what i sometimes get with my BTB, a loose connection at the jack on the bass, but you changed basses and cables, so, it couldnt be that . . . maybe a speaker cable problem?
  3. Moo

    Moo Banned

    Dec 14, 2002
    Oakland, CA
    It can't be a speaker cable since I had 2 cabs with their own cables coming out of the back of the amp and they both cut out. I forgot to put that in the first post :)

    It did sound like a bad jack, I thought I was all slick as this was my first gig where I carried 2 basses.
  4. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Possible that the power was dipping low and would occassionally get so low your amp was shutting down, then kicking back on when the power dip fluctuated back up. Its also possible that you had a loose/sloppy connection at your power cord, either where it plugs into the back of your head, or at the outlet end (or extension cord end). Also possible that an extension cord could have an intermittent internal cable damage, just like a bad guitar cord.

    I use a Furman PM-8 with a voltmeter and an ammeter on the front, shows the outlet power, and the draw of my rig. Both fluctuate when playing, and there have been MANY times when setting up that I was almost in the "danger" range of low voltage that would dip even lower when my rig was pumping (under 105 volts), and could easily be corrected by plugging into another outlet on a different circuit that wasn't already being burdened by other sources of draw.
  5. Good time to buy new cords. The old ones are ready to go bad, and can be used as spares. Change the battery on your bass. All the cheap stuff first.

    If that doesn't fix it, since both speakers cut out simultaneously, its not likely a problem there. Then its probably the amp. Intermittent problems are tough to find/fix/verify they're fixed after you replace something.

    Talk to Eden once you're sure it's the amp. They fixed my intermittent navigator.

    I was bringing a spare preamp wired into the efx loop/tuner out of the nav. When the Nav acted up, I'd bypass it with the tuner mute, that kept me going instantly, narrowed it down to a section of the navigator. Proved it was the nav, not the power amp.

    Snaps and pops can be caused by spikes in power, but to actually cut out the power would have to be really stinky. Its possible, but I bet you're not that lucky. :(

  6. Moo

    Moo Banned

    Dec 14, 2002
    Oakland, CA
    I'm thinking it's something like that. Do they do that? I assumed just the volume would drop.
    I'm ruling that out since if I pull the plug the light goes out immediately and it stayed on through all my troubles.
    Great, more GAS :)
  7. abaguer


    Nov 27, 2001
    Milford, NJ
    I had that happen on a cruise gig where the power supply was fluctuating. I had an EA 600 and the amp's internal protect was shutting it down when the power dipped. Amp worked fine with good electricity.
  8. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    You brought your own amp onto a cruise ship? What's the matter? Can't take 1970's Peavey amps?

    Just use it for the next couple days at home and see what happens. If your cords don't crackle when you jiggle them, then it's more than likely the power sagged and shut it off temporarily.
  9. Does your setup work fine at home? could have just been the places you were playing?

    Or, if you move about a lot, could it be your input jack on the amp (im assuming it would have the same sound as jack problems on the bass which we know its not)
  10. Any chance it was the thermal breaker kicking in and out if the amp was being driven hard?
  11. Moo

    Moo Banned

    Dec 14, 2002
    Oakland, CA
    I don't think so, I set the pre amp to just light the clipping light under the loudest notes and had the master volume at 12 o'clock. It didn't feel hot either. It was a jazz gig with PA support so I was running it a bit lighter than usual.

    Hearing a few people think it may be a power sag is encouraging, I think I'll write a letter to Eden and ask if a power sag will cause a shut down. I'll post the reply when I get it. Thanks all for the help.
  12. Moo

    Moo Banned

    Dec 14, 2002
    Oakland, CA
    Well, not a definitive answer but Eden writes:

    They didn't really say anything that sounds like what happened to me, I hate this intermittent crap! I think I'll try a new tube...
  13. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Tubes are cheap, worth a try, but my money is still on the power sag . . . really . . .
  14. Another thought - I have an Eden Metro that developed a bad solder joint on one of the circuit boards caused by the speaker vibrations.
  15. Matt Call

    Matt Call Supporting Member

    Aug 1, 2004
    Minneapolis, MN
    Hmm... I had a similar experience last night with my GK 400RB head. I'm still trying to figure out what the deal is. The power draw makes sense as to why it might have happened (at least, in my case).

    Hopefully for you, replacing the tube will fix the problem. You'll keep us all updated, right?