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Does low AC power kill amps?

Discussion in 'Amps and Cabs [BG]' started by MuzikMan, May 17, 2011.

  1. Our new "band room" is a single car garage with some of the worst power I have ever seen. We can't run an electric space heater or our PA speakers will distort heavily. The lights dim when we turn our stuff on. We don't collectively know if there is any possibility of damaging our gear with this shoddy electricity. What do you know about this? :meh:
  2. Electricblue


    Feb 1, 2011
    Do use tubes or modelling amps? I'm guessing either of these could be affected by poor power.

    And for safety reason, please please check the house's wiring isnt faulty. That could be DANGEROUS. I mean really dangerous.
  3. Rune Bivrin

    Rune Bivrin Supporting Member

    Oct 2, 2006
    Huddinge, Sweden
    I wouldn't plug anything into that circuit. There's something very wrong with it. Something could catch fire due to too thin wiring, or there's a truly bad grounding somewhere.

    I doubt any reasonably amp would die because of low voltage; that would be the least of my concerns.
  4. It is the drummer's house. Apparantly his father built the garage years ago and did the wiring himself. He knows that the wiring is not in "code" but he is comfortable with it because it has been that way most of his life. It is his PA so he has something to lose as well as us. Are there any engineers in the house?
  5. Electricblue


    Feb 1, 2011
    Try plugging the PA in another socket/circuit in the house, see if the problem continues.
  6. Rune Bivrin

    Rune Bivrin Supporting Member

    Oct 2, 2006
    Huddinge, Sweden
    I bet that was said about Fukushima too...
  7. Hi.

    As a rule of a thumb, low voltage does not kill an amp because the fuse(s) SHOULD kick in before the current draw rises too much.

    That said, I wouldn't use anything of any value if I knew the voltage is less than specified.

    For the rest of his life as well it may be.


    Asking for el. engineering advice over the net is about as useful as asking for legal or medical advice.

    Get a licensed electrician on the site before someone gets killed. Or worse, is injured for life.

    True, You folks use the puny ~110V, but that'll leave a mark as well as the ~230V the rest of the world uses.

  8. BLDavis

    BLDavis Old enough to know better.....too young to care! Supporting Member

    May 21, 2009
    Ellenboro, NC
    THIS...........^ ^ ^ ^
  9. JdoubleH

    JdoubleH Supporting Member

    Jul 10, 2008
    Ellerslie, Georgia
    First off, I don't think I would set foot in that garage knowing what you just told us. It is a very serious fire hazard.

    Second, low voltage can be very bad for electronics, and you can't rely in your fuses for protection. Fuses are designed to blow when current exceeds a certain point at a given voltage. When the voltage is decreased, the current which can pass the fuse can increase (Ohms Law). Increased current means increased heat, which can lead premature component failure or much worse. I'm sure an E.E. could state it more clearly, but every circuit is designed for a specific voltage, and when you stray too far outside tolerances, bad things can happen.

    But again, I would be more worried about death by fire or electrocution than whether my amp can handle it. I would strongly urge you to have a licenced electrician evaluate the wiring and get an estimate for correcting it and ideally adding another circuit. If the owner its unwilling to even get an estimate, find somewhere else to practice.
  10. Electricblue


    Feb 1, 2011
    ^ that. Faulty house wiring is not something to be taken lightly.
  11. Some amps have built in protection. My GB STL6.0 has a threshold of 95 volts, if the power goes below that, the amp protects itself.

    We ran into a power problem at a club once and my amp kept cutting out due to lack of power, it happened the the band after us too, but their guitarists full stack had about as much volume as a 15 watt practice amp.
  12. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Damage isn't likely, most gear is built tough. I'd be concerned over the possibility of a fire hazard with overloaded wiring.
  13. Jim C

    Jim C Is that what you meant to play or is this jazz? Supporting Member

    Nov 29, 2008
    Bethesda, MD
    My little residential remodeling team does about $3M a year and I pull many of the electrical permits.
    No one can tell you how dangerous a condition might be without an inspection although the low votage scenario does bring up a good possibility of an overload condition

    I'm curious as to how the voltage can get so low without the breaker tripping and would be most afraid that the breaker is too large for the branch wiring.
    If it really is too much trouble to spend $100 - 200 for a pro to come in for a quick look, at least run an extension cord to another outlet that is connected to a different breaker; easy way to check is to trun off breakers until the garage outlet is off and another outlet still works
    Spilt the band load so that approx half the power is being drawn from the two sources.
    Smoke detectors and a fire extinguisher sound like the perfect birthday / Christmas presents; would hate for this too go badly for your friend
  14. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    The power available is not enough, and the breaker on that circuit must be too large a rating or you would be having to re-set it. That is a fire hazard.....

    There is a reason the electrical code is actually produced by the "National Fire Protection Association" (NFPA)........... bad wiring causes fires.

    Better find a new space, or practice at very low volume...... with different equipment.

    As for amp damage....it depends on WHAT the equipment is, and how it is made.......

    A normal SS analog amp with transformer is pretty "OK" in general... they draw less and less power as the voltage goes down, and eventually quit or sound so bad you'd know not to use them.

    Most tube amplifiers will have bias that isn't overly affected by low voltage, but SOME might be so made that bias would be reduced at low line in a way such as to possibly damage tubes.... not overly likely, but possible.

    Amps that have a switchmode power supply, i.e. lightweight amps, CAN (not all do) draw MORE current as the voltage drops..... and may not quit until voltage is below 90 VAC (for US). probably won't damage the amps, but may heat the wiring quite a bit, which can be a fire hazard if the wiring is bad/poorly protected.

    Bottom line there is that if the amp isn't sounding bad, it probably isn't being damaged.

    I've seen some bad-wiring....... In our house a previous owner added an outlet in the dining room... they ran about 60 feet of 14 ga ALUMINUM wire, AND they tied it into a 50A dryer outlet, directly........

    if that doesn't ring a bell, the wire was good for about 10A, aluminum wire is a fire hazard in general, and the dryer outlet was therefore capable of providing about 5x what the wire should carry..... a short in that circuit, or something connected to it would have probably caused a fire right away.

    Hopefully your friend's house isn't that bad, but I'd not count on it..... When "Bubba" does wiring, it doesn't turn out good......
  15. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The combination of a 20A breaker and a very long run of 14 ga. wire would explain it, and being a garage I'd bet dimes to dollars that's what he has. I'd bet a lot more that there's no ground rod and distribution box at the garage, and that the nearest ground is at the service entrance. Now, how much do you want to bet said garage has a concrete floor and the outlets are not GFCI, which, combined with the long distance to the ground, makes this not only a fire hazard but an electrocution hazard as well?
    OP, I wouldn't use this place again.
  16. That line made me shiver with fear and laugh at the same time. Did they hang extra clothes on the wire to help them dry too?

    OP: like others have said, your drummer needs his house fixed before it burns down. I'm guessing there will be more than one spot on his electrical system with components stressed from overheating or worse (brittle wirenuts, burnt insulation, melted parts in a worst case scenario).

    Good luck.
  17. Thank you for the responses. I am convinced that the equipment is the least of our concerns at this point. I am going to direct our drummer to this thread so he can read what has been said. I hope he takes heed of the advise to upgrade his electricity, because I won't play there again until he does.

    I understand that asking for an engineer over the internet is not the best way to go about it but this is just my initial inquiry. I don't plan on taking what has been said here as gospel but I have heard enough to warrant furthur investigation directly by a liscenced electrician.
  18. Rune Bivrin

    Rune Bivrin Supporting Member

    Oct 2, 2006
    Huddinge, Sweden
    I'm willing to bet part of the reason the drummer's dad says he's comfortable with the wiring is he's well aware of the shortcomings, and bringing an electrician in would catch him with his "pants down".
  19. Handyman


    Sep 4, 2007
    Austin, TX
    Wow, you're lucky you found that. Houses with aluminum wiring scare the hell out of me. I used to live near a neighborhood that had all the in home wiring done with aluminum. Every year, without fail, one or two of those homes would burn down due to oxidized wiring junctions. And this was generally professionally installed stuff.

    Evil, evil stuff.
  20. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    wow, and to think i used to complain about having to get permits every time i wanted to do something to my house. now i totally get it.

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